Soundcard Oscilloscope #2

Moving on from the previous post regarding the homebrew oscilloscope, I needed to build the calibration / signal generator unit to get the thing doing something other than reacting to mains pickup from the palm of my hand.

Mr Build Your Own Oscilloscope’s book has a nice chapter on how to do this. I won’t bore you with a death by photos, so here’s a select few –

The completed board prior to testing


Peak to peak voltage calibration


Testing prior to boxing


Boxed and completed


I wasn’t overly convinced by the Scope software’s signal generation, which was confirmed by unplugging my probes and watching a perfect sine wave continue uninterrupted on the screen! I’m chalking that up to not having read the manual for the program and a configuration issue because I dug out my other signal/function generator board which is an old Maplin Vellman kit, attached my scope probes and Bobs your uncle, it’s working an absolute treat.


Now I’ve got a fully functioning oscilloscope, with virtual knobs and dials! Once I get my head around the general functionality of an oscilloscope again (it’s been a long time since O Level Physics) hopefully that will translate across to the hideously complex device which is my DS203 and I can put that good use.