Upgrading a Linear Supply with a Current Meter


I bought an Astron RS-20 on the cheap at the local hamfest for my radio. Only problem was the supply was lacking some basic features such as a panel meter for the load current and a banana jack on the front to make the supply output accessible. No problem, with a 200mV digital panel meter laying around, I knew exactly what I wanted to do...  read more »

Stereo Sleep Timer


I wanted to be able to fall asleep listening to my stereo playing the radio, but I did not have a sleep timer fuction on my receiver, so I built this device to add sleep timer functionality to the stereo. The timer can be configured to run in two ranges: 99..1 seconds or 99..1 minutes.  read more »

Digital Thermometer with Memory


This digital thermometer remembers the 12-hours high and low temperatures. This design uses a PIC microcontroller with a built in A/D converter. All the parts are tolerant to temperatures from -40 to 100 degrees Fahrenheit, so you can keep the device outside.  read more »

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