Simple Solar Battery Charger with LM317 Circuit Diagram. This is a solar panel battery charger schematic for AA and AAA rechargeable batteries . A small solar panel would be very good as a source of voltage charger. Building a solar AA battery charger only requires a few components and a simple construction. Solar panels should be well adapted to the battery to be charged or the battery may be overcharged.  If you want to charge batteries with different capacities, then you need to change the solar panels. Since this is a simple solar battery charger that does not automatically turn off when the battery is full. So we need to maintain the charging current is low enough that will not damage the battery even when they are fully charged. An LM317T voltage regulator chip that can be used with a suitable resistor to regulate current. See solar AA battery charger   Solar Battery Charger with LM317 Circuit Diagram

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Here is a solar powered Flasher to scare away the nocturnal animals like bats and cats from the farm yard or premises of the house. The brilliant multicolored flashes confuse these animals and they avoid the hostile situation. It is fully automatic, turns on in the evening and turns off in the morning. The circuit has an LDR controlled oscillator built around the Binary counter IC CD 4060.The functioning of the IC is controlled through its reset pin 12. During day time, LDR conducts and keeps the reset pin of IC high so that it remains dormant. During night, LDR cease to conduct and the reset pin will be grounded through VR1. This triggers the IC and it stats oscillating using the components C1 and VR2. Output pins 7, 5 and 4 are used to power the LEDs strings. VR1 adjusts the sensitivity of LDR and VR2, the flashing rate of LEDs. High bright Red, Blue and White LEDs are used in the circuit to give brilliant flashes. Red LEDs flash very fast, followed by blue and then White. White LEDs remains on for few seconds and provide light to a confined area. More LEDs can be added in the strings if desired. The circuit can also function with 12 volt DC. Animal Repellent Circuit Diagram The circuit uses a solar powered battery power supply. During daytime, battery charges through R1 and D1.Green LED indicates the charging mode. During night time current from the solar cell decreases and D1 reverse biases. At the same time D2 forward biases to provide power to the circuit. Resistor R1 restricts the charging current and the high value capacitor C1 is a buffer for current. Animal Scarer Solar Power Supply

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 In the electronic world D. Mohankumar is the most famous name his creations are very importent every time. Efficiency of a solar charging system depends on the weather conditions. Usually the solar panel gets four to five hours of bright sunlight in a day. If the weather is cloudy or rainy, it affects the charging process and the battery does not attain full charge. This simple hybrid solar charger can solve the problem as it can charge the battery using both solar power as well as AC mains supply. When output from the solar panel is above 12 volts, the battery charges using the solar power. When the output drops below 12 volts, the battery charges through AC mains supply. Fig. 1 shows the author’s prototype.   Fig. 1: Author’s prototype Circuit and working Fig. 2 shows circuit for the hybrid solar charger, which is built around a 12V, 10W solar panel (connected at SP1), operational amplifier CA3130 (IC1), transistor BC547 (T1), 12V single-changeover relay (RL1), step-down transformer X1 and a few other components. Fig. 2: Hybrid solar charger circuit diagram In bright sunlight, the 12V, 10W solar panel provides up to 17 volts DC with 0.6-ampere current. Diode D1 provides reverse polarity protection and capacitor C1 buffers voltage from the solar panel. IC1 is used as a simple voltage comparator. Zener diode ZD1 provides a reference voltage of 11 volts to the inverting input of IC1, while the IC’s non-inverting input gets voltage from the solar panel through R1. Working of the circuit is simple. When output from the solar panel is 12 volts or more, zener diode ZD1 conducts and provides 11 volts to the inverting terminal of IC1. Since its non-inverting input gets a higher voltage at this time, the output of the comparator turns high and the same is indicated by glowing green LED1. Transistor T1 then conducts and relay RL1 energizes. Thus the battery gets charging current from the solar panel through the normally-open (N/O) and common contacts of relay RL1. LED2 indicates charging of the battery. Capacitor C3 is provided for clean switching of transistor T1. Diode D2 protects T1 from back EMF and diode D3 prevents the discharge of battery current into the circuit. When output from the solar panel drops below 12 volts, output of the comparator turns low and the relay de-energizes. Now the battery gets charging current from the transformer-based power supply through the normally-closed (N/C) and common contacts of the relay. This power supply comprises step-down transformer X1, rectifying diodes D4 and D5, and smoothing capacitor C4.   Fig. 3: An actual-size, single-side PCB for the hybrid solar charger Fig. 4: Component layout for the PCB Construction and testing An actual-size, single-side PCB for the hybrid solar charger is shown in Fig. 3 and its component layout in Fig. 4. After assembling the circuit on PCB, enclose it in a suitable box. Use high-gauge (thick) wires to connect the solar panel and the battery to the circuit.  To test the circuit for proper functioning, remove the solar panel from connector SP1 and connect a DC variable voltage source. Set some voltage below 12V and slowly increase it. As the voltage reaches 12V and goes beyond, the logic at test point TP2 changes from low to high. The transformer-based power supply voltage can be checked at test point TP3.

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Build a Simple Solar Powered Long Range FM Transmitter Circuit Diagram . This is very stable, harmonic free, long range fm transmitter circuit which can be used for fm frequencies this one is unique in that it runs completely on solar power. No battery is required. As long as the sun is shining on the PV panel, the transmitter will transmit. The transmitter bug is useful as a “remote ear”, and can be used for anything from listening birds to surveillance work. The mic preamp and oscillator circuits were borrowed from a common circuit found around the Internet, a regulated solar power supply and an RF amp that extends the range of transmitter and improves frequency stability were added.    Simple Solar Powered Long Range FM Transmitter Circuit Diagram Theory The solar power supply consists of a small 18V PV panel which charges a 1000uF electrolytic capacitor. The capacitor keeps the circuit running during brief interruptions of light, such as a bird flying over the PV panel. The 18V is regulated down to 9V with the 78L09 regulator IC to provide a steady 9V supply for the rest of the circuitry. With the PV panel shown above, the circuit will only work when direct sunlight is shining on the panel. A larger panel that can provide 22mA at 12V during cloudy conditions would extend the circuit’s operating conditions. The Electret microphone is biased with a 33K resistor, the resistor value can be changed to vary the amount of modulation and optimize the performance of specific microphones. The microphone signal is amplified by a 2N3904 audio amplifier. This signal is sent to the 2N2222A oscillator stage where it changes the oscillator’s frequency (FM). The oscillator’s operating frequency is set by L1, the 6pF capacitor and the 5-20pF variable capacitor. With L1 wound as specified on the schematic, the circuit will operate near the low end (88Mhz) of the FM broadcast band. The output of the oscillator circuit is taken from a tap on the oscillator coil L1 and fed to the RF amplifier 2N2222A transistor. The output of the RF amp is run through a low pass PI filter to remove unwanted RF harmonics before the signal is sent to the antenna. Specifications Output Frequency: 88Mhz nominal, can cover 88-108Mhz with coil adjustments Input voltage: 11-18VDC Operating current: 22mA @18VDC DC input to RF amp: 81mW RF output power: 40mW (approx.) Construction The prototype circuit shown in the top photo was built using the “dead bug” construction method, it was laid out as the circuit was designed. A second-generation version of the circuit was built using a home-made printed circuit board, this is shown in the second photo. The frequency stability of the transmitter was greatly improved when it was built with the circuit board. Artwork for the PCB is available at the end of this page. It important to mount the oscillator components solidly so that they don’t move around and cause unwanted frequency shift. The component leads for all of the RF wiring should be kept short. The coils were wound on a #2 Philips screwdriver shaft and stretched out a bit. To improve the circuit’s frequency stability, wind the oscillator coil on a 1/4″ form, then heat the coil in an oven at to anneal the metal. A layer of polystyrene “Q dope” can be painted onto the coil to further improve the stability. Another trick that will improve the transmitter’s frequency stability is to build it into a metal box that is surrounded by an insulating material such as styrofoam or bubble-wrap. If the transmitter box is mounted in the shade, it will be less likely to change frequency due to solar heating and cloud shading. Antennas This circuit will work with a variety of antennas. An adequate short-range antenna can be as simple as a 1′ to 2′ wire connected directly to the circuit. A resonant antenna such as a tuned dipole or a vertical antenna will greatly extend the range of the transmitter. A resonant half-wave diple antenna for 90Mhz can be made with two 2.6 foot pieces of wire fed in the middle, using the classic dipole formula: quarter wave length (feet) = 234 / frequency (Mhz). the PV panel and wiring should be kept away from the antenna, or in the case of a short whip antenna, the PV wiring can be run in the opposite direction as the antenna to act as the other half (counterpoise) of a dipole. Alignment The circuit can be aligned in the laboratory by putting 12V to 18V DC across the PV panel to power the regulator. Tune your receiver to a blank spot on the lower end of the FM band and adjust the frequency calibration trimmer until you hear the microphone signal. Turn the trimmer very slowly, alignment takes a light touch. Don’t turn the receiver volume up too much or you will get audio feedback. A frequency counter may be useful for setting the output frequency. It may be necessary to retune the frequency a bit after the circuit has warmed up in the sun. The output capacitor should be tuned for the maximum transmitted signal, this setting varies with different antennas. The best way to do this is to connect the antenna to the transmitter and monitor the signal with an oscilloscope (100 Mhz bandwidth) connected to a nearby antenna. Adjust the control for the highest signal. If you have a receiver with a signal strength indicator, that can also be used for monitoring the transmitter’s output level. Adjustment of the output capacitor will pull the oscillator frequency a bit, it will be necessary to alternate between oscillator and output adjustments to fully align the circuit. Use Place the PV panel in the sun and tune your receiver to the bug’s signal, listen to the world outdoors. An analog receiver is best for picking up the signal since, unlike a digital receiver, it can be fine tuned to track the signal. I use a 1970s vintage Pioneer receiver to good effect. Once the bug’s temperature has stabilized, its frequency should not drift very much. The microphone enclosure and placement can be tuned to optimize sound reception in a particular direction. A good directional microphone can be made by putting the mic element into one end of a short piece of PVC pipe. Inserting a thin tube of porous foam into the pipe can lower the resonant nature of the cylinder. Parts 1X GM 684 60 mA 18V PV panel (available from Electronix Express) or equivalent 1X 78L09 voltage regulator IC 1X 1N4001 diode 1X 2N3904A transistor 2X 2N2222A transistors 1X 1000uF 25V electrolytic capacitor 1X Electret microphone 4X 100nF capacitors 2X 22nF capacitor 1X 1nF capacitor 1X 3pF silver mica capacitor 1X 6pF silver mica capacitor 1X 10pF silver mica capacitor 1X 20pF ceramic disk capacitor 1X 27pF ceramic disk capacitor 2X 5-20pF (or similar) miniature variable capacitor 1X six hole ferrite choke or equivalent 1X 100 ohm 1/4W resistor 1X 470 ohm 1/4W resistor 1X 10K 1/4W resistor 1X 20K 1/4W resistor 1X 33K 1/4W resistor 1X 47K 1/4W resistor 1X 1M 1/4W resistor 1X 1-3/4″x3″ copper plated blank printed circuit board 1′ length of #20 tinned copper hookup wire for making two coils 1X weatherproof plastic box (recommended) 

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Most of the systems are powered by AC mains. Uninterrupted power supply systems (UPSes) are there as a back-up to power the systems when mains supply is interrupted due to a power cut. A UPS differs from a standby generator in that it will provide near-instantaneous power by supplying the energy stored in batteries. In an online UPS, batteries are always connected to the inverter, which is always on, so that no transfer switches are necessary when power disruption occurs. In an offline UPS, the inverter circuit is switched on when mains are not there. UPSes are available off-the-shelf, and one can select the system as per one’s requirement, back-up time being one requirement. However, one can construct a UPS of one’s own choice. Here is a circuit of an offline UPS, which a hobbyist can make at a reasonable cost. The capacity of the UPS is 350VA, so it can be used for any equipment with a load below 350VA. The UPS can be upgraded to 1kVA by making just a few changes. Circuit and working The circuit diagram of the mini offline UPS shown in Fig. 1 has the following four sections: Section 1: Mains/inverter change-over section Section 2: Inverter section Section 3: Battery-status-indicator section Section 4: Oscillator section Above-mentioned sections and their interconnections are appropriately marked in the circuit diagram. Mains/inverter changeover section. The circuit of this section is built around step-down transformer X1 (230V AC primary to 12V-0-12V, 500mA secondary), a 12V DC, 3C/O (changeover) relay (RL1) and a few other components. 230V AC mains is connected to the circuit through connector CON7. Output of the UPS is available at connector CON8, which is actually a 3-pin socket. Mains voltage is rectified by diodes D1-D2 (1N4007). The full-wave rectified output is smoothened by capacitor C1. DC voltage so generated is applied at pins 10 and 11 of relay RL1. When mains voltage is there, the relay gets energised to affect the changeover to connect the mains to the output of the UPS. The circuit is not on a PCB and has been wired externally. Relay contacts in the circuit diagram are shown in a de-energised state of the relay. Inverter section. This section comprises transformer X2, npn power transistors 2N3055 (T1 through T8) and power diodes 1N5407 (D3-D4). Transistors, which are eight in number, are connected in two banks. The number of transistors per bank will depend on the required VA rating. The prototype has been made for 350VA rating by using four transistors per bank. The number of transistors required per bank for different capacities are: 550VA – Five 650VA – Six 1000VA – Seven Fig. 1: Circuit diagram of the mini UPS This circuit is also not on a PCB and has been wired externally. Transistors T1 through T8 have been fitted on the same heat-sink. Mounting of transistors has to be done in such a manner that their base and emitter are not in contact with the heat-sink. The metal body of the transistor is the collector. Collectors should be separated from the heat-sink. This is done by using mica separators between the heat-sink and metal body of the transistor. In short, all three terminals should be separated from the heat-sink. The arrangement is shown in Fig. 2. Interconnections of transistor terminals, transformer X2, diodes D3-D4, battery-status-indicator section and oscillator section are shown in a combined circuit diagram (Fig. 1). The heat-sink should also be isolated from the UPS box. Fig. 2: Mounting of transistor 2N3055 on heat-sink     Fig. 3: Details of the 3C/O relay Fig. 4: PCB of the oscillator and the battery-status section Fig. 5: Components of the PCB Battery-status-indicator section. This section monitors the state of the battery. It is connected to the battery by CON3-CON4 combination. Connect these as per polarity of the 12V battery. Overcharge status of 14.4V is set with the help of preset VR3. Overcharge status is indicated by LED2. We have to switch off S1 to protect the battery from overcharging. During normal charging, no LED (LED1 or LED2) will glow. If S1 is off, the rectifier circuit formed by diodes D3 and D4 will be disabled, which, in turn, will stop further charging of the battery. Lower limit of the battery is set at 11.3V with the help of preset low level of the battery, which will be indicated by LED1. Switch S1 has to be closed to restart the charging of the battery. Load should be disconnected when battery voltage is lower than 11.3V and mains voltage is not there. Oscillator section. This circuit comes into action when mains voltage is not there. It, along with two banks of transistors T1-T8, will generate low-level AC voltage (15V-0-15V) at terminals of transformer X2, which will be stepped up by transformer X2. The circuit is built around NE555 timer (IC2), dual JK flip-flop 4027 (IC1), transistors SK100 (T11-T12) and BC547 (T9-T10), voltage regulator 7805 (IC3) and a few other components. NE555 timer is configured in astable multivibrator mode. Frequency of the timer is set to around 200Hz with the help of preset VR1 in order to get around 50Hz line frequency at CON1. Output of the timer from its pin 3 is fed to pin 3 (CP2) of second flip-flop of IC1 as clock pulse. Output of this flip-flop from pin 1 (Q2) is used to clock the first flip-flop. Outputs Q1 and Q1 are applied to the bases of transistors T9 and T10, respectively. Transistors T11 and T12 amplify these outputs to about 2.2V, which are applied to base terminals of transistors T4 and T8 for further amplification to 12V. Con1 and Con2 are used to connect outputs from the oscillator section to the two transistor banks. The circuit is powered by a regulated 5V DC provided by voltage regulator 7805. Input to the regulator is the battery voltage, which we get by connecting Con5 to Con6. Battery voltage reaches pin 1 of regulator through pin 9 and pin 3 of relay RL1 and switch S2 is closed. When mains voltage is present, pin 9 and pin 3 are disconnected due to activation of the relay. Power supply to the oscillator section is interrupted, resulting in deactivation of the inverter circuit. Relay RL1 Relay RL1 affects the necessary changeover required in the system due to the presence or non-presence of mains voltage. It is a 12V, three contacts changeover (three-poles  double-throw) relay. The arrangement of poles and contacts is shown in Fig. 3. The coil of the relay is between terminals 10 and 11. Terminals 7 and 8 are shorted. Connections of remaining terminals of the relay are shown in circuit diagram (Fig. 1). Working of the circuit The UPS works in two modes: 1. When AC power is present 2. When AC power is absent When AC power is present. When AC mains power is present, transformer X1 gets 230V AC input mains supply. Relay RL1 is therefore energised. Terminals 7, 8 and 9 of the relay come into contact with terminals 4, 5 and 6, respectively. Phase of the incoming AC mains supply gets connected to terminals 4, 7, 5 and 8 of the relay and the output socket where we connect the load. In this manner, mains are transferred to output socket CON8 of the UPS. Fig. 6: The final assemblage enclosed in a cabinet (front panel)    Fig. 7: The final assemblage enclosed in a cabinet (internal wiring) When switch S1 is closed, the phase of the input mains gets connected to 230V tapping of transformer X2 through terminal 5 as it is in contact with the terminal 8 of the relay. As the neutral connection is common, transformer X2 acts as a step-down transformer. 230V AC is stepped down to 15V-0-15V AC and rectified to DC voltage by a full-wave rectifier (diodes D3-D4). Capacitor C7 is connected across the center tap of transformer X2. It is not included in the PCB. It is recommended to use a current limitter (say 4.7-ohm, 20W resistor) in series with positive terminal of the battery using suitable arrangement. The value of this current limitter will depend on your requirement, so it is not shown in the circuit here. DC voltage so generated is used to charge the battery. At the same time, terminal 9 of the relay comes into contact with terminal 6, which disconnects power supply to the oscillator circuit and deactivates the inverter circuit. Switch S1 should be open when the battery is fully charged, which will be indicated by lighting up of LED2. When AC mains power is absent(power cut). When AC mains power is off, transformer X1 does not get 230V AC supply. Relay RL1 therefore does not energise. Terminals 7, 8 and 9 of the relay come into contact with terminals 1, 2 and 3, respectively. Terminal 9 is connected to the positive terminal of the 12V battery, which is extended to the oscillator circuit. Inverter circuit comes into action. Transformer X2 is now a step-up transformer. AC voltage from 240V tap of transformer X2 is connected to terminal 1 of the relay. As terminals 7 and 8 are in contact with terminals 1 and 2 of the relay, 240V AC gets connected to output socket CON8. Neon lamp N1 is connected between terminal 2 and neutral. It glows when the UPS is on. The output is connected to 240V tapping because there will be a voltage drop when load is connected to the UPS. Construction and testing Combined actual-size, single-side PCB for the oscillator section and the battery-status section is shown in Fig. 4 and the component layout in Fig. 5. If needed, the PCB can be cut into two portions along the dotted line and mounted separately. Rest of the circuit has been wired using connectors. The final assemblage of the mini offline UPS is enclosed in a cabinet as shown in Fig. 6. The internal wiring is shown in Fig. 7 and the rear panel is shown in Fig. 8. All switches, indicators and terminals for connecting the battery and output socket are to be placed aesthetically on the front panel of the cabinet. Fig. 8: The final assemblage enclosed in a cabinet (rear panel) Fuse F1 (1A) is used to protect the device from any short circuits. All connections should be made very carefully. The load should not exceed 350VA. For troubleshooting, check voltages at various test points as listed in the table. Caution . Please be careful as the circuit operates on 230V AC.

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 This project is an open source (hardware & software) DDS generator, based on: smart TFT module, AD9834, LM7171 fast amplifier. Description The homemade function generator is a quite common project on the internet. We can find different ways to do it: – The quick & dirty way based on a DDS module bought on eBay – The analog version based on a MAX038 / XR2206 – The “clean” way based on a FPGA and a fast DAC (e.g. http://www.circuitben.net/node/14) – The software way (e.g. Arduino + R/2R DAC) From my side, I wanted a small one which could fits my needs without being too expensive. According to me, such generator should at least: – Be easy to use – Output a signal from 1Vpp to 10Vpp (+/-5V), from 0 to 1MHz – Have a low profile – Without electric hazard (shall work on a 12V DC) Tiny DDS – Open source DDS generator Project Schematic Choosing the DDS chip I first started to look for a cheap DDS chip on eBay; you have to be careful because most of DDS chips have only a sinusoidal output. Since I also want a triangular output, I have chosen the AD9834. According to its datasheet, this component is able to output a frequency of 37.5MHz from a clock of 75MHz… But do not expect a clean waveform at such frequency: without an internal PLL, this signal would be defined by only 2 points. From my personal experience, I consider that a waveform shall be defined by 10-20 points to be well restituted. Relying on a 75MHz clock, the maximal output frequency would be 7.5MHz… This is not a very good performance for a professional equipment (even if the cheapest generators do not go above 4MHz), but it is quite reasonable for a hobbyist project. The AD9834 can be found at $5 on eBay. Amplitude control The amplitude of the AD9834 can be controlled through different ways: – Constant amplitude of 1Vpp (by default on most COTS), by wiring a resistor between the FS_ADJUST pin and the ground: this is quite annoying because an additional external amplifier will be need to set the amplitude to a desired level. – Variable amplitude, by wiring a potentiometer between the FS_ADJUST pin and the ground: this solution is really easy to implement, but it will not allow a software management needed, for example, by the amplitude modulation. – Software variable amplitude, by wiring a DAC to the FS_ADJUST pin. This solution is a bit more complex, but it will allow to implement some useful functionalities. I choose this way. The amplitude will be set by the microcontroller of the smart TFT module (PIC32MX795). Unlike the other manufacturers (Atmel, ST…), Microchip did not include a DAC on their $10 chip… An external DAC is needed (an AD5310 found on eBay for $0.8 – 10 bit / SPI, SOT23-6 package). A small voltage divider is put between the DAC and the FS_ADJUST pin in order to transform the 0-3.3V of the DAC into 0-1.2V handled by the AD9834: Notice: the logical levels are reversed: the minimal amplitude is reached when the DAC output is 3V3 and the maximal amplitude is reached when the DAC output is 0V. AC coupling The AD9834 generates a signal with a non-null offset, variable according to the amplitude. At this point, this offset is very annoying and shall be removed. Two possible ways: – A high pass filter (a simple RC filter): this solution ensures an ideal AC coupling, but is problematic for the low frequency signals (a huge RC filter would be needed for frequencies below 100Hz) – A differential amplifier: it is possible with the AD9834 because this component already has a differential output (IOUT / IOUTB pins). This solution makes the AC coupling effective even for very low frequencies, even for a DC signal. Therefore, the AC coupling will not be “ideal”: a small offset will be injected, and possibly some additional distortions due to the tolerance of the components (OPAMP & resistors). Nevertheless, it remains the best way according to me. The ratio R15/R12 is set such as the maximal voltage outputted by U6 is +/-3.3V. Offset control Nothing difficult here: we just have to generate a DC signal between -3.3V and +3.3V. I use another AD5310 with a small OPAMP: Notice: here again, the logical levels are reversed: the minimal offset is reached when the DAC output is +3.3V and the maximal offset is reached when the DAC output is 0V. Final stage Here, we have 2 signals: the one coming from the DDS (between -3.3V and +3.3V, AC coupled) and the one coming from the offset control (between -3.3V and +3.3V too). We just have to mix these 2 signals and amplify them to get a +/-5V output: The LM7171 is able to output more than 100mA; nevertheless, the current is limited through a 100R resistor. A small LC filter is also implemented before the main output for filtering the 75MHz clock residual. PWM output Nothing complex here: a simple CMOS gate for buffering the PWM output of the microcontroller. I tried to use a fast comparator on the triangular output of the DDS, but the jitter was too important; I finally gave up this solution. Analog input Very minimalist… A simple resistor for limiting the input current, and a common Pi filter. The sampling frequency is not very high (~ 1KHz) because the internal ADC of the microcontroller is also used by the touchscreen inside an ISR. Power supply / regulators The generator is powered by a standard 12V plug. Some switching regulators produce the 5V (for the smart TFT module) and the +/-7V (used by the analog stage). The 3.3V comes directly from the smart TFT. The LT1616 are an expensive components on Farnell, but I found these on eBay for $0.8. Notice that any buck regulator should do the job here (+5V@200mA, +/-7V@200mA). PCB The whole schematic can be easily routed in a small PCB (smaller than a credit card). The PCB is composed of 2 layouts, with a common GND plan. The LM7171 shall be routed with care: due to its topology (fast OPAMP – 400MHz), a bad layout will make it oscillate. For this reason, I also add a footprint for a small 1pF capacitor: if the layout is not correct, I should be able to limit the oscillations with it. Assembling the board The PCBs (from SeeedFusion): The finished board: Assembled with the smart TFT: Software After a first quick & dirty attempt, I had to enhance the interface look; this one is working properly, but I admit that the old win95 look is really outdated. Moreover, there is a flickering issue on some widgets which are highly solicited (e.g. the frequency valueBox). The new interface is based on a brushed metal background, with dark widgets. I have also implemented the double buffering for the concerned widgets: The new look is more modern (according to me; I’m not a graphic artist :s). The interface is still very reactive, but the memory footprint literally explodes (more than 90% of the flash memory is used). The user interface is composed of 4 “pages”: – DDS (sinus/triangle waveform, with frequency / amplitude / offset control) – PWM (PWM signal only) – ARB (arbitrary waveforms & modulations) – A menu page Sinus / triangle waveform generation These waveforms are directly generated by the AD9834, just by configuring its internal registers through the SPI bus. Nevertheless, a small detail shall be handled by the program: the frequency register is coded on 28 bits, split on two 16 bits registers. The access to the frequency register is not an atomic operation and shall be buffered first (through the FREQ0 / FREQ1 registers). Arbitrary waveforms generation I use the internal DAC of the AD9834 to generate these signals: this solution allows to keep the whole analog stage as is (same amplitude / offset control). For using the internal DAC, I configure the AD9834 with a triangle signal of 0Hz; then, I set the phase register to obtain the desired output voltage. Some basic waveforms are available, such as saw tooth, exponential, noise, sin(x)/x… It is also possible to draw a waveform and play a wav file. However, there is a bandwidth issue: the AD9834 is accessed through a SPI bus, and even with a 20MHz clock, several microseconds are needed to send a single sample on the output. At the end, the microcontroller cannot provide more than 100kSPS (kilo Sample Per Second). Above this rate, the program is ran very slowly (most of the CPU time is spent into the ISR). Go further Even if this generator works properly, I have to admit that its electrical characteristics are closer to a gadget than a professional equipment (SNR below 45db). However, it would be easy to enhance its performances by modifying some components: The DDS chip A DDS such as the AD9102 is much more powerful than the AD9834; besides its more accurate DAC (14bits vs 10bits), its internal LUT can be reprogrammed: where the PIC32 can only provide 100kSPS, the AD9102 can provide up to 180MSPS (1800 time more). Unfortunately, this device is more expensive ($15/u at 100u) and is available only in LFCSP package (quite hard to solder). The analog stage The power supply should be changed first: the +/-7V coming from the buck regulators are obviously problematic (the output signal has some noise – 1.5MHz @10mVpp). A simple power supply based on a toroidal transformer and some 78xx / 79xx would be better. The LM7171 OPAMPs should also be changed by a more appropriate chip (a current feedback OPAMP for example). DAC The 10 bits of the AD5310 might not be the wisest solution for this application: for 10Vpp, 1LSB is equivalent to ~10mV, which is pretty good… if you use the whole range of the DAC! I reduced the range from 0-1023 to 0-920 due to the tolerance of the components, leading to an 11mV/LSB resolution. A 12 bits DAC would be a better solution here, thus a true voltage reference (the current one is derived from the 3.3V supply).  Author: Philippe Duboisset

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 This is the Simple Ac line Voltage Announcer Circuit Diagram. The range of this simple ac-voltage monitor is 100 to 140 Vac, with a resolution of 1 V. The speech processor interprets an 8-bit binary input code from an analog-to-digital converter. The processor`s pulse-code-mod ulated output then passes through a filter and an amplifier before driving tbe circuit`s speaker to vocalize the corresponding number. Each time switch S1 is _pressed, the speech-processor program enun ciates tbe monitored voltage readings from 100 to 140 V, depending on the code at the input of a 27C64 EPROM.   Simple Ac line Voltage Announcer Circuit Diagram The voltage-monitoring circuit consists of a bridge rectifier, filter capacitors, and a 10-Kilload resis tor. A divider, RA and RB, limits the input voltage to a maximum 2.55 V. The aid converter, IC4, then sends the voltage reading to tbe 27C64 EPROM, ICS. Pressing Sl sends a negative transient pulse to the write, WR, input of the aid converter, IC4, which initiates a 100-ttS conversion process. 

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Hyundai Creta SUV Features: Variants: 1.6 Petrol Dual VTVT (Base, S, SX+), 1.4 CRDi (Base, S, S+), 1.6 CRDi VGT (SX, SX+, SX(o)), 1.6 CRDi VGT (AT) (SX+) 1.6L Dual VTVT Petrol Engine 1.6L CRDi VGT / 1.4L CRDi Diesel Engine Seating Capacity: 5 Mileage: 21.38 kmpl 1.4L Engine & 19.67 kmpl for 1.6L (MT),

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Just like the Ninja 250 which remained unchanged for almost a decade, The Kawasaki ER-6f and ER-6n have been with Kawasaki for a long time. Sure, the… Visit the link above to read the full story.

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For the second year in a row the Bonneville Speed Week has been cancelled due to improper salt conditions on the surface of the iconic Bonneville… Visit the link above to read the full story.

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Mafahari wawili Bongo Movies, Aunt Ezekiel na Wema Sepetu ‘Madam’ wamezidi ‘kusherehesha’ bifu lao baada ya kupigana vikumbo kwenye mgahawa unaojulikana kama Snow Cream na kuchuniana kama vile hawajuani. Kwa mujibu wa gazeti  la Risasi, Wema ndiye aliyekuwa wa kwanza kuingia kwenye mgahawa huo na wapambe wake kisha baada ya muda kidogo kupita, Aunt pamoja na watu wengine nao walifika na kukaa meza nyingine. Habari zinadai kuwa baada ya Aunt kukaa, walitupiana macho na Wema bila kupeana salamu ingawa Wema hakuwahi kumuona mtoto wa Aunt tangu ajifungue.   Inadaiwa kuwa baada ya Aunt kumaliza kula Ice Cream na kundi lake, waliinuka na kuondoka zao na kumuacha Wema na marafiki zake.   Alipotafutwa  Aunt ili aweze kuzungumzia kitendo hicho na bifu lao lisema;   “Jamani unajua kila mtu alienda kwa ajili ya kazi zake na ndiyo kama tulivyokutana kila mmoja alikuwa yupo na taratibu zake, sioni kama ni bifu, sina comment,” .

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Habari Njema kwa wale wapenzi wa Bongo Fleva kundi la Navy Kenzo limerudi na ngoma yao mpya iitwayo Game waliomshirikisha Vanessa Mdee (VeeMoney).   Kama wewe ni mpenzi wa miondoko flani ya dancehall yenye fleva ya kibongo basi Navy Kenzo na VeeMoney wamekurahisishia kazi kwenye ngoma hii.

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Rais Obama na Familia yake, hii ni kama TBT hivi… picha moja ya zamani zamani kabisa.   Kila ukiingia kwenye Mitandao ya Kijamii Kenya stori nyingi kubwakubwa na zenye headlines ni kuhusu ujio wa Rais Obama.. sio kitu kigeni kwa sababu hata alivyokaribia kuja TZ stori zilikuwa nyingi vilevile na zinazofanana na hizo.   Leo nimekutana na pichaz nyingine pamoja na stori nyinginyingi kuhusu Nairobi na ujio wa Obama.

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Jeshi la polisi Mkoa wa Pwani  limefanya msako mkali katika mapori mbali mbali  na  kufanikiwa kuwakamata   watuhumiwa  wa ujambazi  27 pamoja na   risasi 153,bunduki 2  mabomu 3  ambavyo  walikuwa wakivitumia katika matukio ya uharifu.   Kwa mujibu wa  Kamanda wa Polisi Mkoa wa Pwani Kamishina mwandamizi Jafari Ibrahimu amesema kwamba watuhumiwa hao wamekamatwa baada ya kufanyika operesheni katika magenge yaliyopo vichakani na kuwakuta watuhumiwa hao wakiwa wamejificha pamoja na silaha walizokuwa wanazitumia kufanyia uhalifu   Ameongeza kuwa  wameamua kufanya  operesheni  hiyo  kutokana na kuongezeka kwa uharifu katika baadhi ya maeneo ya Mkoa wa Pwani na kuwakamata watuhumiwa hao  ambao wengine walikutwa na vifaa mbali mbali ikiwemo visu mapanga,pamoja na nyaya tatu za milipuko ya mabomu.   Katika zoezi hilo pia waliweza  kukamata madawa ya kulevya aina aya bangi gunia 18 na mirungi kilo 124,lita 88 za pombe ya moshi pamoja na mitambo yake mitatu ya kutengenezea noti bandia 370 na meno ya tembo.

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Aliyekuwa Waziri wa Mambo ya Ndani ya Nchi na Mbunge wa Songea Mjini, Dk. Emmanuel Nchimbi (pichani), amefunguka kuhusu mambo kadhaa na kueleza kuwa  Watanzania wanapaswa kuelewa kuwa kutofautiana katika vyama vya siasa ni jambo la kawaida katika nchi yenye demokrasia. Dk. Nchimbi alisema hayo jana ikiwa ni siku moja baada ya Chama Cha Mapinduzi (CCM) wilaya ya Songea Mjini kuikataa fomu ya kuomba kuwania ubunge aliyochukuliwa na wananchi kwa madai haikuwa imekidhi vigezo. “Ninachowambia Watanzania tuzoee kutofautiana, kutofautiana katika vyama vyetu ni jambo la kawaida katika demokrasia, tunaweza kutofautiana katika mapendekezo, lakini tukifika kwenye maamuzi tunakuwa kitu kimoja kuunga maamuzi tuliyoafikiana na huo ndio utaratibu mzuri wa kujenga demokrasia,” alisema. Dk. Nchimbi ambaye alikuwa akihojiwa na kituo cha Radio One jana asubuhi, alisema demokrasia ya kutoelezana ukweli siyo demokrasia bali demokrasia ya kweli ni ya uhuru wa fikra. Alisema mtu ambaye hapendi CCM iwe shwari ni mtu ambaye  haitakii mema nchi na kwamba hana mpango wa kuhama chama hicho kwa sababu amelelewa na CCM. Aliongeza kuwa taarifa za kwamba yeye na makada kadhaa wamehojiwa na chama kuhusiana na kauli walizozitoa wakati wa vikao vya uteuzi wa mgombea urais kuwa hawakuridhishwa na mchakato huo hazina ukweli. ”Mimi nimekulia CCM na bado nitaendelea kuwa CCM kutokana na misingi ya kifikra na kisera, sasa kama kuna mtu anayewaza kuwa naweza kuhama CCM hiyo ni fikra ya kijinga sana,” alisema. Kamati ya Siasa ya CCM wilaya ya Songea Jumapili iliyopita ilikataa kupokea fomu ya kugombea ubunge ya aliyojaziwa Dk. Nchimbi na baadhi ya wakazi kwa madai kuwa haikukidhi vigezo. Hata hivyo, mwezi uliopita Dk. Nchimbi aliandaa mkutano wa wanachama wa CCM, viongozi na wananchi na kuwashukuru kwa ushirikiano waliompatia katika kipindi chake cha uongozi kisha kuwatangazia kwamba hatagombea tena ubunge katika jimbo hilo mwaka huu. Dk. Nchimbi alikuwa akitajwa kuwa huenda atagombea katika Jimbo la Mbinga Magharibi lililopo wilayani Nyasa ambalo lilikuwa likishikiliwa na marehemu Kapten John Komba, aliyefariki  dunia mapema mwaka huu

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Mbunge wa Karatu kwa tiketi ya Chadema, Mchungaji  Israel Natse, amejitoa rasmi katika siasa na kurudia kazi yake ya uchungaji katika Kanisa la Kiinjili la Kilutheri Tanzania (KKKT) Dayosisi ya Kaskazini. Akizungumza na mtandao huu kwa njia ya simu ya kiganjani jana, alisema makubaliano yake na chama walimwomba agombee kipindi kimoja tu na sasa anapisha mwingine. “Mimi ninarudi kwenye kazi yangu ya uchungaji naachana na siasa, huu ndiyo wito wangu nilioitiwa na mungu wa uchungaji,” alisema. Akizungumza kwa njia ya simu ya kiganjani, Katibu wa Chadema Mkoa wa Arusha, Calist Lazaro, alisema kwa Jimbo la Karatu waliochukua fomu za kugombea ubunge ni Lazaro  Masai, Fransisca  Duwe, William Kumbalo, Kwamala  Aloyce na Pascal Gutt.

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Baada ya vuta vikuvute ya muda mrefu, hatimaye leo Chama cha Demokrasia na Maendeleo (Chadema) kinatarajia kumtangaza mgombea wake wa urais katika mkutano maalumu utakaofanyika jijini Mwanza. Habari zilizopatikana na kuthibitishwa na viongozi wa chama hicho Kanda ya Ziwa Magharibi na makao makuu zilisema kuwa leo mgombea huyo atatangazwa mkoani hapa huku zikibainisha kuwa anayepewa nafasi kubwa ni Katibu Mkuu wa chama hicho, Dk Willibrod Slaa. Taarifa hizo zimekuja wakati kukiwa na tetesi kuwa chama hicho kilikuwa kinafanya mazungumzo na waziri mkuu wa zamani, Edward Lowassa aliyekuwa anawania urais kupitia CCM na kutemwa katika hatua za awali, huku vyanzo mbalimbali vikisema mazungumzo hayo yanachukua muda mrefu na kuna uwezekano mkubwa wa kutozaa matunda. Jana, Mwenyekiti wa Chadema, Freeman Mbowe pamoja na baadhi ya wabunge walikaririwa wakitoa matamko ya kumkaribisha Lowassa kuingia Chadema lakini kwa sharti la kufuata kanuni na taratibu za chama hicho, lakini Dk Slaa alisita kumzungumzia kiongozi huyo akiahidi kuzungumza mambo yatakapokuwa sawa. Mratibu wa Operesheni za Chadema Kanda ya Ziwa Magharibi, Tungaraza Njugu alisema mgombea huyo (bila kumtaja jina), atatangazwa katika mkutano wa hadhara utakaofanyika kwenye Viwanja vya Magomeni, Ilemela kuanzia saa nane mchana. Njugu alisema katika mkutano huo, viongozi wakuu wa Ukawa wanatarajia kuwapo na maandalizi yake yamekamilika. “Kesho (leo) tutakuwa na mkutano mkubwa kwenye viwanja vya Magomeni,” alisema Njugu na kuongeza: “Mgombea urais kupitia Ukawa atajulikana hapo, kwani tunatarajia viongozi wakuu wa Ukawa watamtangaza.” Katika mazingira tofauti, akihutubia mkutano wa hadhara mjini Geita juzi, Mwanasheria Mkuu wa Chadema, Tundu Lissu alidokeza jina la Dk Slaa kama mgombea urais wa chama hicho, kitendo kilichoibua hamasa na umati kumshangilia, lakini akawapoza akisema ulimi umeteleza. Alipoulizwa kuhusu mkutano huo, Mwenyekiti wa NLD, Dk Emmanuel Makaidi alikiri kuwa leo kulikuwa na mpango wa kumtangaza mgombea wa Ukawa, lakini alidhani ingekuwa Dar es Salaam, hivyo kwa kuwa wameamua iwe Mwanza angefanya utaratibu wa ndege ili aweze kuwahi. Mwenyekiti wa NCCR- Mageuzi, James Mbatia hakupatikana kuzungumzia mkutano huo, lakini Katibu Mkuu wa chama hicho, Mosena Nyambabe alisema hakuwa na taarifa hizo, hasa kwa kuwa vikao vya mwisho vilivyofanyika Jumapili na Jumatatu vilihusisha wenyeviti wa vyama pekee. Hata hivyo, alisema ilibidi mgombea huyo atangazwe ama jana au leo. Chama cha CUF kimekwishatangaza kuwa kinasubiri uamuzi wa kikao cha Baraza Kuu la Uongozi litakaloketi Julai 25 kuamua juu ya hatima yake ndani ya Ukawa. Alipotakiwa kudokeza ni nani atasimama kuwakilisha Ukawa, Njugu alisema jukumu hilo ni la viongozi wa juu na kwamba yeye akiwa kiongozi wa Kanda anatambua mgombea urais wa Ukawa atatangaziwa Mwanza leo. Mkutano huo utakaorushwa moja kwa moja katika televisheni, pia unatarajia kumpokea Mbunge wa Viti Maalumu (CCM), Ester Bulaya aliyetangaza kukihama chama hicho juzi bila kuweka wazi anakohamia. Hata hivyo, mbunge huyo ambaye tayari ameweka wazi kupitia ukurasa wake wa Facebook kuwa atawania ubunge katika Jimbo la Bunda Mjini, amekaririwa akisema hatima yake itakuwa hadharani leo.

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Good news for adventure riders, The specs of Honda’s highly anticipated Africa Twin or Honda CRF1000L have been leaked out on the Africa Twin… Visit the link above to read the full story.

[via MotorCycleFeed.com – Must-Read global Motorcycle News site]

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Mtu mmoja aliyefahamika kwa jina la Mosha Mahona ameuawa na wananchi baada ya kuwachoma kwa kisu abiria watano waliokuwa kwenye daladala linalofanya safari zake kati ya Posta na Ubungo Simu 2000. Kamanda wa Polisi Mkoa wa Kinondoni, Camilius Wambura alisema jana kuwa tukio hilo lilitokea juzi saa moja usiku katika eneo la Magomeni Usalama na Mahona aliuawa kwa kushambuliwa na wananchi baada ya kudhuru abiria wenzake. Kamanda Wambura alisema Mahona alikuwa ndani ya daladala hilo lililokuwa likitokea Posta kwenda Kituo cha Simu 2000 ndipo alipotoa kisu hicho na kuwashambulia wenzake sehemu mbalimbali ya miili yao. “Mahona aliuawa na wananchi baada ya kuwachoma kwa visu abiria watano ambao walipelekwa katika Hospitali ya Taifa ya Muhimbili kwa matibabu. Majeruhi hao wanaendelea vizuri,” alisema Wambura. Wambura alisema baada ya Mahona kufanya kitendo hicho walianza kumshambulia na kusababisha kifo chake. Aliwataja abiria waliochomwa visu kuwa ni; Daudi Mwenera, Geogre Nomani, Bakari Andrew, Zawadi Mwaipopo na Eda Kiwege. Alisema polisi wanaendelea na uchunguzi ili kujua sababu ya marehemu huyo kufanya kitendo. Alisema mwili wa marehemu umehifadhiwa katika Hospitali ya Muhimbili kwa uchunguzi zaidi. Hilo ni tukio la kwanza la aina yake kwa abiria kuchoma visu wenzake.

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Kinyang’anyiro cha ubunge wa viti maalum katika mkoa wa Singida  kimeibua mapya, baada ya Mwenyekiti wa Jumuiya ya Wanawake wa Chama Cha Mapinduzi (UWT) Wilaya ya Ikungi, Christina Hamis, kutishia kususia kuingia kwenye ofisi za jumuiya hiyo na kuhama chama. Mwenyekiti huyo anakusudia kuchukua uamuzi huo kwa madai kuwa Katibu wa CCM wa wilaya hiyo, Aluu Segamba, anamlazimisha amuunge mkono mgombea ubunge wa Viti Maalumu (CCM), Wema Sepetu. Alisema atachukua maamuzi ya kuhama chama na kujiunga na Chama cha Demokrasia na Maendeleo (Chadema) kutokana na vitendo anavyofanyiwa na baadhi ya viongozi wa CCM ngazi ya wilaya na Mkoa wa Singida kwa sababu hamuungi mkono msanii huyo wa Bongo movie na Miss Tanzania 2006. Christina alisema pamoja na kwamba yeye ni Mwenyekiti wa UWT wilaya, jambo linalomshangaza ni kuona mambo yasiyoridhisha yakifanyika ndani ya nyumba za mawakala wa mgombea ubunge huyo. Alisema tangu mchakato umeanza amekuwa akipokea kauli za kashfa na matusi kutoka kwa watu wa karibu wa Wema akiwamo mama yake, Mariam Sepetu, kutokana na kutomuunga mkono mtoto wake. Mariam Sepetu alipoulizwa kuhusu kutoa maneno ya kashfa kwa Mwenyekiti wa UWT, alisema hawezi kujibu mambo yoyote kuhusu kiongozi huyo. Christina alisema kwa mara kadhaa amewasilisha malalamiko yake kwa Katibu wa CCM wilaya ya Ikungi, Segamba kuhusu matusi, kashfa na vitisho anavyopata, lakini hapewi ushirikiano. “Nimemweleza Katibu wa Wilaya mambo nayofanyiwa, lakini niliishiwa kuambiwa siwezi kupata msaada wowote kwenye ofisi hiyo na kwamba niachane na Wema kwa sababu ameletwa na kiongozi mmoja mkubwa wa serikali, mawaziri  na mtoto wa kigogo agombee ubunge,” alisema. Kwa mujibu wa mwenyekiti huyo, maamuzi ya kugombea ubunge kwa Wema kumetokana na kushawishiwa na vigogo wa serikali na kwamba viongozi waliopo mkoani hapa wanatakiwa kumuunga mkono. Christina alisema baada ya kuona hasaidiwi, aliwasilisha malalamiko kwa Katibu wa UWT Mkoa wa Singida, Anjela Mirembe, lakini jibu alilopatiwa ni kwamba Wema ameletwa na wakubwa na hivyo aachane naye. Alipotakiwa kuzungumzia malalamiko ya mwenyekiti huyo wa UWT wilaya ya Ikungi, Mirembe alithibitisha kupokea malalamiko hayo kwa maneno, badala ya maandishi kama taratibu za kiutendaji wa kazi za kiofisi zinavyoelekeza na hivyo kushindwa kuyafanyia kazi. Katibu wa UWT wilaya ya Ikungi, Yagi Kyaratu, alisema alipokea malalamiko hayo kutoka kwa mwenyekiti wake na kuyawasilisha kwa Katibu wa UWT mkoa wa Singida. Katibu wa CCM wilaya ya Ikungi ambaye pia ni kaimu katibu wa CCM Mkoa wa Singida, Segamba, alipotafutwa ili aweze kujibu tuhuma zilizoelekezwa kwake alijibu kuwa yupo kwenye kikao. Kwa upande wake, Wema alipotafutwa jana, simu yake hukupatikana na hata alipotumiwa ujumbe mfupi wa maandishi, hakujibu hadi tunakwenda mitamboni.

[via LEKULE]

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