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

Contact-less tachometer counts up to 99kRPM

There may be some situations when it is hard to use a tachometer only because it is impossible to read revolutions per minute mechanically. The only way is to read RPM without touching rotating shaft.   This great design was constructed by Ibrahim Kamal who used an IR signal to transmit and receive it reflected from reflective stripe fixed to rotating shaft. Device is controlled by AT89S52 microcontroller which counts reflected pulses and displays value on LCD. RPM counting algorithm uses last three times between pulses and this way constantly gives instant RPM value. RPM meter consists of two parts: microcontroller board and IR proximity sensor connected to microcontroller board via simple 4 wire cable. Project files are available for download in a single zip. Continue reading

PIC18F2550 based harmonic distortion meter

This simple device, designed by Wichit Sirichote, measures the quality of AC voltage. The device measures 3rd harmonic which is used to find the distortion value comparing to fundamental frequency.   Device calculates DFT of signal which is captured via step down isolation transformer and 10-bit ADC. Testing showed that clean sine wave gives less than 0.5% of distortion, while square wave gives about 33%. Project description includes detailed measurement theory outline and practical examples as well. Project is built on test board which was developed for general purposes. Source code is available for download. Continue reading

Interfacing RFM12 transceiver module

RFM12 is a transmitter and receiver module in single board. It can be powered by using 2.2V to 5.4. it makes ideal module for embedded systems. Module communicates via SPI interface.   Wigbert Picht and Dirk Milewski have made simple Atmega8 tesboard, where RFM12 module is soldered as SMD element and can be configured with jumpers. There can be any sensors connected to this board like temperature. Schematic and sample Bascom AVR program are available for download. Continue reading

Control 3×7 segment LED display with one MCU pin

ibsimed1 have developed a single I/O-Pin 3×7-Segment Display board. It only needs one microcontroller I/O pin and power source.     The board itself is very simple but idea is great – it uses three serial to paralel converters 74HC164 which activates LED segments. As it is said – display board uses only one I/O pin which also serves as CLK source for serial to paralel converters (from 500kHz to 8MHz). Synchronisation is done by connecting microcontroller I/O pin to CLK through RC Low-pass Filter. There is an AVR code example which can be run from any AVR microcontroller. In this Example PB0 is the general I/O-Pin, but this can be easily changed. Project can be downloaded Here. Continue reading

Connect up to 16 satellites to one receiver with AVR DiSEqC switch

DiSEqC-Switch is widely used in individual satellite systems to connect up to 16 satellites to one receiver using cascading method. This switch uses other cheap DiSEqC-Switches ver1.0 with four satelite heads each or simply connects directly to satelite heads and this way acts as simple switch.   Schematic diagram is based upon standard DiSEqC-schematic solutions except connections between the Attiny13 and the output switches. This solution allows to reduce number of transistors. PCB is available in P-CAD format. Decoding algorithm of incoming DiSEqC messages are explained here. Also you can check out Testing Device for DiSEqC-Switches that is uses 1.0 or 11 protocols . Continue reading

Blue clock gift project

Want to please your friends or family, then make Christmas gift by yourself. This is nice looking blue LED clock project which can be made without significant efforts. Clock looks really nice when decorated with smoked gray acrylic. It has two push buttons for selecting time and alarm, while another two are for setting hours and minutes. The project heart is Atmega835 microcontroller and PCF8563P RTC module. Clock source is written by using WinAVR compiler. Continue reading