Fuzy Logic Wash Machine circuit using PIC16F84

Timing sequence like the above description, can be implemented with many way, by using discrete electronic components, timer, using a program or a microcontroller or microprocessor, etc. Because I am learning the PIC microcontroller for right now, I will implement this function using this microcontroller, but for you who familiar with another kind of microcontroller my adapted it to your purpose. By using PIC micro, it can be made more compact. First I plan to make 2 buttons, 1 for set the timer and another for reset the timer or for the emergency stop push button. Then to know the timer works or not, I need a visual display. For this purpose I will use 7-segmen display showing the rest of the timer. To run the motor sequence of course I need a pair of relays (power relays, about 3 Amperes output), one for forward and another for reverse option. I will use the very common family of PIC micro, ie : 16F84A, because this is the most popular type and very simples used and very much used. Also can be obtained easily in the market. But this is the medium type of PIC micro family. It has 1kByte of memory (EEPROM type) and 13 I/O pins. It can be reprogrammable thousands times. Because the I/O just only 13 pins, I used a BCD to 7-segmen chip. So it will left a few I/O pins for expanded in the future. You can omitted this chip for timing sequence purpose and save one IC price, because the I/O just exactly enough.



source:http://www.dsaprojects.110mb.com/electronics/timer/washing_mc.html

Electra Distorsion Circuit

It is supposed to sound amazingly like a Tube Screamer. With the exception of the diodes, the circuit is the same as the circuit for the Electra Power Overdrive module, which was fitted inside some Electra guitars in the 70’s. It’s important to use germanium diodes to get the right sound. Silicon is supposed to produce more power and less distortion. Get gives 0.4 volts of signal out, Si gives 1.4 volts. The values of the collector and emitter resistors can be changed to give more or less gain and distortion. The unit is not just a hard diode clipper, as the diodes load the output of the transistor and modify its gain as they turn on, giving softer clipping than you would expect.

Temperature Logger hardware schematic

In this project we use a PC for GUI display and the homemade data converter board using the AVR microcontroller. The circuit is built with the ATmega8. The chip has the onchip 10-bit resolution A/D Converter. Temperature sensor are connected to the 6 channels ADC input. You can connect up to 8 sensors with the ATmega8 TQFP package. Schematic for the ADC board is shown in Figure 1. The board consists of the ATmega8, the temperature sensor (LM335), and the serial interface. The on chip firmware controls reading the ADC converter, receives commands from PC and sends the reading to PC. The microcontroller is running with 8MHz crystal oscillator, if we use the internal RC oscillator, the external crystal may be omitted. The ATmega8 DIP version has 6 channels analog input. If you need up to 8 ADC input, you can use ATmega8 in TQFP package, or you can use another AVR microcontroller with the on-chip ADC.

We use LM335 temperature sensor. It can measure the temperature using two wires remotely. The chip produces an output signal that is proportional to the Celcius temperature scale. The trimmer POT is used to calibrate the correct output voltage at known temperature, for example 2.98V @ 25° C.



source :http://www.kmitl.ac.th

ATMEGA8 Fuse Bit Security

The first attention should be paid to
clock sources. There are Four bits controlling Atmega8 clock sources:
CKSEL0, CKSEL1, CKSEL2, CKSEL3.

Atmega8 can have 4 different clock sources:

• External Crystal or Resonator;
• External Low Frequency Crystal;
• External RC Oscillator or Calibrated Internal RC Oscillator;
• External Clock source.

THIS SAMPLE USING PONYPROG

1. 8MHz Crystal with slowly rising power:
   
2. 2MHz ceramic resonator fast raising power:
3. 32768kHz resonator stable frequency at startup:
4. External RC 4MHz oscillator with internal C enabled fast rising power:
5. If you want to drive maximum from your Atmega: then select 16MHz fast rising power:

Digital Meter ATMega8 Circuit

The circuit came out to be very simple and compact. The ATMEGA8 is the lowest pin count AVR controller that I could find that has an onboard 10 bit A-to-D converter. It had no problem directly driving the four digits delivering an average approximately 50 milliamps to the display. The on-chip clock oscillator also saved some parts. I am not sure whether the 8 uH inductor and 0.33 uF decoupling capacitor on the analog VCC was necessary, but I used them as a good practice. Better to put a couple of extra parts on the board than to take the chance of having to take the board back and add them later. The schematic above shows an ISP (In Circuit Programming) connector, which I had originally built onto the board so I could debug the firmware, using the crash-and-burn method - write the code and see if it runs. After I was satisfied with the performance of the meter, I cut off the portion of the board that had the ISP connector on it. Power for the chip is regulated with a 7805 regulator. In this particular case, I used a TO-92 LM78L05 regulator. Measuring the current into the 5 volt input, I find a maximum of about 56 milliamps current drain, when displaying 08.88 volts. When powered from a 9 volt power source, the dissipation of the LM78L05 will be 224 mW. With a 200 degrees C per watt thermal resistance, junction temperature should be about 45 degrees above ambient. A little more calculation showed that the maximum safe input voltage to the LM78L05 is just a little above 12 volts if my maximum ambient temperature is 40 degrees C. In Don’s case, where he would power the meter from 30 volts, it would be best to use a TO-220 version of the LM7805.



source : http://makecircuits.com