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27 Feb 2008


Check out this nifty touchkeyer (for CW or “continuous wave” Morse code) ham operator Jonathan Haynes ( KC7FYS) built into his Altoids-housed ATS-3b high-frequency CW radio transceiver:

I put whiteboard marker on my fingers and pressed them on a piece of paper to get this footprint. The idea of sculpting them from PCB material came to me when I was trying to sleep. Ha ha. Next time I’ll use thicker copper with a thicker substrate. [via]

Touchkeyer on Altoids-based HF radio – [Link]

27 Feb 2008


Mike writes –

i would like to suggest this site, which presents an advanced infrared hacking tool, using a simple AVR, has a learning function and 2mb of flash for learned tv remote codes. It even has an usb port, all in software on the AVR (no special usb chip required)! [via]

Unzap – USB TV-B-Gone with learning function – [Link]

25 Feb 2008


Want to try CPLD devices? It is good to start with development board for that. Here it is – a nicely made XC9572XL CPLD development board.

Development board has all I/O ports available. For quick prototyping there are six 7 segment LED indicators connected, also there are 8 LEDs connected via ULN2003A. Board is also equipped with two non symmetrical adjustable RC oscillators based on 74AC04 IC and two hybrid oscillators, piezo sounder and more. Available files for download: circuit, and operating video sample. This source may be a good start for developing your own CPLD board. [via]

Development board for XC9572XL CPLD – [Link]

25 Feb 2008


This is good looking and practical device that may be useful in many areas where count down timer is needed (no bombs please). Its time can be adjusted in range from 1 minute to 99 minutes. It displays time sequence on BCD decoded 7 segment LED display. When count down finishes – timer sends a control signal to relay.

Complete design is made on wiring technique, so no PCB is available. Project is very well described with circuit operation animations what is really helpful for circuit beginners. Source code is also documented well with flow charts. Assembly code and hex file may be downloaded here. [via]

Adjustable count-down timer with PIC16F84A microcontroller – [Link]

25 Feb 2008


Having the doorbell ring just when you fell asleep, after your all-night soldering frenzy, can be a real annoyance. This simple project will allow you to turn off the buzzer or bell for 10 hours, allowing for a nice long nap. [via]

DIY Door bell privacy – [Link]

25 Feb 2008


This is a single transistor FM transmitter that is about the size of a standard AA battery. The site has all the schematics and technical specifications needed to complete the project. Let the bugging begin! [via]

Simple FM transmitter – [Link]

25 Feb 2008


This ultra-compact electrocardiogram device was made using an ARM training/development unit –

It is a STM32 Primer with two copper foils placed on each side of the front circle. These two metal foils are the ECG electrodes. User can place his/her both thumbs on the copper foil to start the operation. The ECG trace is scrolling on the LCD display. The heart rate calculated and display on the top of the LCD display while the LED and beep sound indicating the pulse detected. [via]

Compact standalone ECG – [Link]

24 Feb 2008


This SMD op-amp project uses the TI RC-4560 dual op-amp chip and a salt water-etched PCB. The builder got the op-amp as a free sample from Texas Instruments and scavenged all of the SMD resistors from old hard drive electronics. The results are not pretty, but they’re functional. The circuit used (with some changes) is the Chu Moy design found here. The CMoy circuit is not SMD.

RC4560-based headphone amplifier – [Link]

24 Feb 2008


This is a microcontroller based POV(Persistence of Vision) that is Hand-powered POV. This project developed by Dimme. The project based on Atmel ATMEGA16 microcontroller.

Hand-powered POV – [Link]

24 Feb 2008


Freeloader Solar Charger is the pocket size solar charger and can store the power up to 3 months.You can use it to charge your electronic gadgets such iPod, mobile phone, PSP, PDA anytime, anywhere.This device is suitible for any traveller.

Freeloader Solar Charger – [Link]





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