Turn-key PCB assembly services in prototype quantities or low-volume to mid-volume production runs

PIC12F675 controlled electrical key-lock

For building 12 button key-lock you don’t need microcontroller with many ports. Ivica Novakovic has a nice demonstration on how low pin count microcontroller with ADC can be used to read many keys. Key-lock itself is simple. It controls two relays where electromagnets or motors can be attached. In key-lock circuit there are only one one wire used to read buttons. Of course there are also VCC and GND (power supply) needed. Author also included simple piezo buzzer for sounding keys. Each keypad is positioned between resistor voltage dividers so when one of buttons is pressed, ADC reads a voltage drop. This way each button provides different voltages when pressed. As there is 10 bit ADC used, there can be 1024 different voltages read, but in reality there has to be voltage range left for one button, because voltage may fluctuate. For 12 buttons each button has 85 value range what is enough for reliable operation. With more precise resistors and stabile power supply there can be more buttons interfaces if needed. Project files and firmware are available for download.[via] Continue reading

Stepper motor controller on PIC

Stepper motors seems to be always interesting topic. And there is a lot of information about controlling them around the internet. Albert La also has been playing with steppers using PIC microcontroller. He constructed simple circuit with PIC16F84 microcontroller, TIP120 Darlington transistor pairs, and 4050 buffer IC for circuit protection. Wrote simple program which is able to run stepper motor with 7.5 degrees per step. This circuit can serve as stepper motor tester for instance picking right wiring, measuring revolution speed and so on. [via] Continue reading

Simple PIC voltmeter with LCD

This is very beginner project on how to read analog DC voltage with PIC and display it on LCD display developed by sprut.   Voltage is read with 10 bit ADC input. Input is connected directly to RA0 pin so be careful with measured voltages. Higher than VCC voltages may damage PIC microcontroller. If you are not sure better connect protecting Schottky diodes on the input. ADC can measure with 4.8828125mV accuracy when VCC=5V. Download assembly source code if you want to experiment more. sprut also has more info on his site about electronics, PIC microcontrollers. Site is in German language, but any online translator can help. Continue reading

Probably the simplest 3 channel IR remote control

This is a simple 3-channel remote control project developed by sixca. It uses two PIC12F629 microcontrollers for both sides: receiver and transmitter.   Remote control is based on RC5 protocol which is most popular among manufacturers and hobbyist because of its simplicity. Transmitting is done by pressing one of three buttons representing channels. Rx side has IR receiver which decodes transmitted signal and gives logical “1” outputon one of three pins. These pins can control anything including relays, lamps, motors and other external devices. You may expand functionality by modifying source code. Continue reading

Precise LC Meter on PIC16F84A microcontroller

Almost every multimeter has ability to capacitance measurement ability, but inductance measurement is included in more advanced or specialized multimeters. Especially if you like to work with RF technologies, power supplies, LC measurement capability is vital. Instead of buying one I suggest to build one and have pleasure to use accurate LCD metter built by yourself. Design is very simple so it is easy to replicate. It can measure inductances from incredibly small inductance 10nH up to 100mH and capacitance from 0.1pF up to 900nF with auto-ranging capability. Information is displayed on 1×16 LCD module. Zero out button allows to set initial inductance/capacitance for precise measurement. Project page has detailed description on developing LC meter and putting in to nice box. All you have to do is to assemble circuit and flash the program. If you have some troubles in building it, you may buy kit with preprogrammed PIC microcontroller. Continue reading

Four channel burglar alarm on PIC

If you want to build simple and reliable burglar alarm system from few electronic parts try this – PIC based four channel alarm system. It monitors 4 normally connected (NC) input channels. If at least one of the channels loop is disrupted it triggers alarm and shows Activated zone by flashing one of LEDs.   Project is really well documented. Because project was developed as final project for Electronics coursework, it has more that documentation – it also includes deep analysis of each part of circuit. So material should also serve as nice tutorial for PIC starters. Or you can just simply build the project, grab source code and flash it. Continue reading