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

Interfacing Nokia 6100 color LCD to AVR controller

Thomas Pfeifer have connected Nokia 6100 132×132 pixel 4096 color LCD to AVR microcontroller. LCD is also used in Nokia 6100, 7200, 6610, 7250 and 6220. He connected LCD to Atmega8 microcontroller:   As there are two types of displays: with Epson chipset(S1D15G10) and Philips(PCF8833), he wrote code for Philips chipset. Firmware is written in AVR-GCC language where image can be uploaded via serial cable. Also there are few videos view sample video on how it works AVR-3D-Engine. Continue reading

Amateur ECG monitoring device

This is very simple ECG monitorin device with no protection and isolation circuitry. Also signal quality isn’t good enough to interpret data seriously. But circuit works and shows ECG pattern.   Signal is amplified and filtered via Analog devices instrumental amplifier AD620. Signal then is sampled with Atmega8 ADC and sent to LabView via USART. Refik didn’t include the whole circuit, just amplifier module, but it is not hard to recreate microcontroller part as there are standard connections to ADC and USART. Program is written in assembly language where ADC reads data and sends it via USART. Continue reading

Programmable DC pover supply

This is must have tool in you LAB. The idea was to build microcontroller based DC power supply witch was easy to build and was cheaper than in market.   Device was built by using only standard components. Device is capable to provide up to 30V 2A. Power supply unit can be controlled by PC using i2ctalk program which can be run under Linux, Windows, Mac OS X and Solaris. Software can be found here. Dont forget to check for an updates. You can order this power supply unit as a kit from Tuxgraphics online shop. Kit includes additional documentations and circuit diagram. Continue reading

AVR DDS waveform generator

This AVR DDS generator can generate signals from 1Hz up to 65535Hz. Thanks to well known DDS algorithm frequency limits can be much higher, but signal resolution drops in higher frequencies. Current range is enough for most of audio signal equipment testing. DDS algorithm is written in software where Atmega8 runs at maximum 16MHz. There are several signal waveforms available: sine, square, sawtooth, triangle and reverse sawtooth and pseudo-random noise.   Signals are stored in lookup tables as DDS algorithm requires. Signal output is organized via simple R-2R ladder DAC. LCD signal goes through shift register, this way only 3 MCU pins are used, while other serves for other purposes – buttons, other outputs. Project is well documented PCB and source files included. Author states that he will build another DDS generator with improved control and variable signal amplifier at the output.   Continue reading

Movement tracker with accelerometer

This device so called Station Master is small key ring sized device which tracks movement in the train. As train goes, device vibrates, but when train stops, it generates alarm after predefined number of stops. So you don’t miss your station. Device is based on Atiny13 microcontroller and MMA7260 3 axis accelerometer from Freescale. Alarm is generated by cell phone vibro motor.   Project files include schematic and assembly program which is very compact due to smart program optimisation – especially filter part, where movement signal is detected from noise pattern. Continue reading

Power AVR microcontroller with AA battery compactly

Tired of using huge batteries in embedded design? Well Guy from Spritesmod managed to power AVR microcontroller from single AA battery with simple circuitry which is driven by AVR microcontroller itself. As industrial devices uses DC-DC converters to rise voltages like from 1.5V to 5V and so on, there is same principal used as well, just DC-DC converter control is done bu AVR MCU itself.   He didn’t use dedicated PWM control chip, but managed to drive converter with PWM generated with Attiny13 this way occupying one timer for this. Here is this fancy circuit. Of course to before MCU can generate control signal it has to start, for this there is starter button used, which rises voltage for short time to suitable when pushed. Then microcontroller starts and continues powering itself. With MOSFET switch efficiency of circuit reaches up to 73 percent. Main advantages of such powering method are low part count, soft poer off. But in other hand efficiency is still quite low and there is timer and one MCU pin occupied. Continue reading