Get a Scope

I really am a sucker for mailshots (hmm. Perhaps I shouldn’t put that in the blog). Anyhoo, I got a mailshot from Cool Components advertising the above (or actually the slightly cheaper version 2 which you don’t seem to be able to get any more). So I bought one. It is a tiny digital storage oscilloscope which costs around 80 quids or so. I reckon this is extremely good value. It has an SD card that you can use to store waveforms and the whole thing is powered by a Cortex A3 and open source, so you can even put your own firmware in there if you fancy it. It is powered from a rechargeable battery and will go up to 1 MHz which for me is fine.

If you are not sure what an oscilloscope is, it lets you “see” electrical signals. It draws a plot of the voltage in the signal as it changes over time. The original ones used a cathode ray tube that drew a single dot on the screen. The dot was moved across the screen at a regular rate by a timebase generator and the value of the voltage in the signal was used to control the height of the dot. If the signal was regular then you could take a a peek at the waveform and see what it was doing.  Newer ones are of course digital. The input voltage is converted into numbers which are then used to draw a graph on the screen.

Sometimes, when a circuit just doesn’t work you need to take a look at what is happening. A voltmeter will tell you if there is anything on the wire, but not how it is changing over time. If you have any hardware aspirations I think a little device like this is a pretty good investment, and it only costs around the same as a couple of video games.

Comments

[Charlotte]

that's cute, contemplating finding a portable oscilloscope for when I'm at uni, surviving on a multimeter for now but would be good when checking the signal of my thumb joystick. my dad cracked out his old style one the other day for testing what particular pins on my microcontroller were set to do in the C code...his is about the size of a desktop computer tower and hadn't seen the light of day in years :P

[Rob]

A scope is a useful thing to have. You don't need them very often (unless you build a lot of hardware) but when you need one, you really do need it. I'm feeling kind of guilty about buying the thing really, I've already got one that I don't use that much, but it really was a bargain and I can pass my existing one down to number one son.

[Rob]

Hmm. Three "really's" in one paragraph. That won't get past the sub-editor....