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

One-hand wearable keyboard with USB interface

The latest keyboard version is an evolution of older one which was based on ATtiny2313 and could be connected to PC via PS/2 and was based on Attiny2313 microcontroller. Latest wearable keyboard is ported to at90usbkey demo board and can be connected to PC via USB. Keyboard is able to produce all usual characters with few keys that are pressed in groups. It may be convenient to use it on special conditions like for portable computers, palmtops and so on. If you want to study it more John W. McKown provides project files and compiled firmware for free. Continue reading

Simple programmable robot project

Al Williams have sent us a easy to make robot project, which is featured with two IR LED sensors, two servo motors modified for continuous rotating and GP3 general purpose control board based on PIC microcontroller. Probably the most interesting part of this project is the way robot is programmed. It uses a GP3EZ software which allows to use very simple “point and click” programming style. You don’t need to write code – you just have to go through user interface and select program flow steps. This is really easy – especially for starters. More about GP3EZ programming style here. Continue reading

Ultraviolet LED controller for PCB exposure

One of most critical parts of PCB fabrication is exposing of photo-resistive layer with ultraviolet light. You cannot underexpose and overexpose if you want to get clean and crisp PCB image. The best solution is to use automatic exposure controller. Controller is based on PIC16F628A microcontroller. It has an LCD to show remaining time. Relay switch which is used to control UV LEDs. Generally there could be other sources of light if needed. Time value is entered and started with four push buttons. When timer runs buzzer generates a sound requesting your attention. Software for PIC microcontroller can be downloaded form here. Project is documented in non English language, but any on-line translator does the job. Continue reading

DTMF extension for microcontroller system

Telephone lines that maybe found in your house may be used not only for making calls but also for other purpose like home automation, remote device control. To make it possible there is an interface between phone line and microcontroller system needed. This DTMF extension is universal module that can be connected to any microcontroller platform. It detects DTMF tones and decodes them to binary digits that can be easily read by microcontroller, which can decide what tasks to perform. DTMF decoder is based on CM8888 chip which is ideal for interfacing with MCU. Here is an example source code for interfacing with AVR ATmega8535 microcontroller which is written for WinAVR compiler toolset. Continue reading

PIC based Palm keyboard Morse code application

Palm keyboards are special keyboards that fold up in to compact box. These keyboards communicate with palm via RS232. Hard to say if they are still in production, but probably you can find one in your loft. Palm keyboards use non standard RS232 connector, so PIC based Morse code application uses a fabricated socket. Application itself is simple – it beeps Morse code depending on key is pressed. Application is written in ASM language for 16f628a microcontroller. Continue reading

AVR based Rogue video game

This is a portable battery powered Rogue-like video game- The dungeons of Doom. The game runs on Atmega32 microcontroller. So it can be plugged to any TV set with NTSC decoder. AVR to TV interfacing is done with well known video DAC made of 3 resistors and is tuned to 75Ω TV input resistance. The whole project including 9V battery fits in a box for Altoid mints. Project source code can be downloaded here. Game code is far not complete, like only one monster implemented, also player inventory has no different weapons and items. But I guess there is still some fun to se some action on TV screen. Continue reading