DIY 8051 Network Cable Tester

DIY 8051 Network Cable Tester.

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.

Simple handheld POV clock

Handheld POV clock showing time.

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.

Small RS232 to TTL converter

RS232 to TTL converter.

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!).

Serial port controlled AC power outlet strip

Serial port controlled outlet strip.

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.

Desoldering a QFP SMD IC using a candle.

Old NIC with just removed RTL8019.

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

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.

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