DIY Oscilloscope

Occasionally I need to use an oscilloscope to look at a wave form.  They cost about £200 which is quite expensive for something I would only use a couple of times a year.  They are also quite complicated and it is potentially difficult to find the view that you want.

A few years ago I used PC based software which worked in conjunction with a PC sound card to work as an oscilloscope.  The input is taken from signal and ground into the PC jack plug which is + or - 0.7V.  The sound card then provides 16 bit samples at 44,100Hz.  A quick look reveals that these programs are still available, for example Christian Zeitnitz or TorVergata.  A problem with using the PC sound card is that you have to make sure your input does not exceed 0.7V, otherwise you could damage the sound card or PC.

More recently I have seen Arduino based solutions and as soon as you start looking there are loads of them.  The first one I chose to look at is at electronicsforu. A simple sketch runs on an Arduino nano to capture a signal on an ADC (Analog to Digital Converter) pin and send it through the serial interface to the PC.  A simple program pcscope.exe runs on the PC to discover the arduino and display the serial data as a wave form.  This is about as simple as you can get and it works without other components on a 5V circuit and only requires a signal/ground connection to the circuit under test.  I may look at other more sophisticated solutions in due course. The pictures below show a bit of debuggin on my Ben Eater clock module flashing at about 1Hz.  The arduino nano takes its signal from the 555 timer output via the white wire and the PC displays the output wave form.

Of course once you start looking at these free solutions other ideas come up.  Oscilloscope for ipad costs £10 and looks good for audio signals but it is probably not suitable for electronics.  More fun would is a build your own JYE Tech oscilloscope, available from Amazon for £30.  It wouldn't be very accurate but it should do the basics.

A real oscilloscope would be worthwhile if I want to spend any time learning how to use it.  Probes and electronics need to be good quality to get results so spending £200 on something like a Hantek DSO5102P (reviewed by my heros Rui and Sara Santos at RandomNerdsTutorials) would be reasonable.