This is a very cool project for all hobbyists.It is a PIC16C71 based 4-digit LED frequency-counter & Volt-meter. Some hard to find parts used in the previous version, which are out of production for some time, has been omitted. A rather early PIC16C71 has also been replaced by 28-pin device PIC16F876. The later is capable of driving 4 digit LED display in multiplexed mode while measuring frequency, power supply voltage as well as handle two analog inputs to display SWR/PWR signal strength in a bargraph manner. There is no need for external LED display driver chip as well as external data EEPROM since it is already implemented in PIC16F876.
50 MHz frequency counter, voltage meter & SWR/PWR indicator - [Link]
This is a bench power supply with regulated DC outputs -12V, -15V, +5V, +12V, +15V, and variable and one +35VDC unregulated output. This bench supply almost exclusively upon Andrew Kilpatrick’s design.
DIY Bench Power Supply - [Link]
Features:Infrared remote control ,Serial port for computer control ,Ability to press the top of the lamp to turn it on/off or change modes (not in prototype),The color can be independently controlled at each corner ,Smooth, beautiful color transitions
Control Color LED - [Link]
This is a PIC based water level detector.Why I should PIC ? First I have a lot of them for my DIY projects,second I want to use this project with 4.5V batteries and PIC Micro has sleep mode which has very low power comsumtion,so the life of the battery can be extended.Most of time of this circuit operates in sleep mode and wake-up from sleep through watchdog time-out every about 2 second.
Water level detector with PIC12F683 - [Link]
The U232 is a RS-232-to-USB conversion module for replacement of PCB mount DB-9 and DB-25 connectors. It offers a quick upgrade to USB of an existing product’s legacy RS-232 serial port by replacement of the Dsubminiature (DB) connector. No electrical or physical changes are required – just replace the existing serial port connector with the U232 module on the circuit board. The USB port on the host device supplies all power for the module. Several models are available for both DB-9 and DB-25 connectors with long and short footprints. [via]
RS-232 to USB conversion - [Link]
Bob writes in with a rundown on how to repurpose an old USB cellphone data cable for rs232 communication.
About three years ago,I bought a USB data cable to use with T610 mobile phone. I can’t remember what is model just know it is made in China. But now I have a new model mobile phone and my USB data cable not used at all. So I want to modify it to use with my microcontroller projects that use rs232 communication like a USB to RS232 converter. If you have this cable and want to modify this article may help you.
Old cellphones are great for scavenging µC project parts like small LCDs, motors, etc. [via]
Use a cellphone data cable for microcontrollers - [Link]
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]
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]
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]
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]