DIY Oscilloscope

A friend of mine convinced me to buy a kit to build a simple oscilloscope. At first, I thought it would not be very useful because the analog bandwidth is not more than 1 MHz. On the other hand, most of the times I have needed an oscilloscope, it has been to debug simple and slow data lines, such as SPI and RS232, so I decided to give it a chance. It was a real challenge to solder, because there were a lot of really small surface mount components (mostly capacitors and resistors) to solder. After a few evenings of soldering I was ready to try it out.

Here are a few pictures. First of all I measured the oscilloscope's built-in 500 Hz test signal:



Second, I measured the 9600 bps serial output from my HP48SX calculator. You can see that the output is not proper RS232 signal levels. I guess this is a way to save battery power on the calculator:



After a little testing, I am really impressed by the oscilloscope, especially as it was priced just over 500 swedish kronor (less than $80). It was also fun and interesting to solder all the small parts!