Mini Oscilloscope
Bought this mini oscilloscope as a kit on eBay (from China as usual) for £20. The main board with the surface mount components was already completed, but the electrolytic capacitors, an inductor, diode and all the switches had to be soldered in along with the display. There is no case as such, but clever use of 2 extra pieces of pre-cut PCB and 4 stand-off fixings make for a nicely finished unit. I might make sides for it out of 3mm foam board if the notion takes me. When I initially switched it on, nothing much happened except the backlight was on. Checking the troubleshooting guide helped and it turned out that the potentiometer for adjusting the LCD contrast needed a bit of working up and down to clean its track. The 'scope can measure up to 2 MHz which is fine for my needs and has sample and hold and a frequency meter function. I tested it with the composite video signal from my Arduino TV-Out board and got a nice sync waveform at the right frequency. More information ...