Designed and built during October 2000, this was my first ever microcontroller based project. This one was inspired by an Edmund Scientific instruments catalog. I didn't see anything like this in that catalog but there were a lot of nice, year 2000 modern multipole cable testers, that made me think and imagine what would be the simplest possible network cable tester that I could quickly build.
I've posted its schematic and firmware source code.
It is also called a wand clock. This project was inspired by a Circuit Cellar contest project. As soon as I saw it I wanted my own version. This is probably the simplest POV clock that can be easily made. As far as I remember, the Circuit Cellar contest project used a mercury switch as position indicator but I didn't have one so I made a simple inertial switch with the leg of a diode and a ball of solder.
I've posted schematics and firmware.
This is a small and compact RS232 to TTL level converter that I use to connect a computer or calculator running terminal emulation software to some devices with 5V compatible serial ports. I like to use it with my HP49G running dTerm v1.1 by James D. Purdy (thanks a lot!).
Another old project. This is a modified power strip that allows to control each of its six outlets independently via a serial port. The outlets are controlled with TRIACs. There is no heat sinking so it can only handle relatively low power loads. I had no problems using it with 60W lamps, but the original purpose was to automatically turn off my soldering irons (25-50W), which very often I left connected, hot and forgotten for days in some cases.
I've posted the schematics, and firmware source code.
Never do this. I mean it. It is dangerous, it is wrong, you may get hurt, your tools, your stuff or your house may be damaged. I did this because I didn't have proper tools at hand and it was a do or die weekend situation. You must use proper air soldering and desoldering tools. In Youtube you can find excellent videos on how to do this in a better manner.
If you want to see what is what I did, read on...
Small LED dot matrix sign
This (5 rows by 28 columns) scrolling LED dot matrix digital sign was designed and built during November 2000 as a hobby and was my second ever microcontroller project. After building and programming it I left it working continuously for about 21 months, after that it was shelved and I only powered it occasionally when somebody wished to have a look at it.
Further down in this article are the schematic and its firmware source code.