Learning electronics

Electronics desk

I am a man of many interests. I generally feel there is not enough time to do and learn all the things I would like. What with work and other commitments. Sometimes I do a good job of reining in my sudden interest in something new, reminding myself that I already have lots of hobbies and not enough time spent on them. Sometimes I get involved in an idea or a project, only for it to fall by the wayside amongst many other priorities. Normally my wife likes to remind me of the other projects I’ve started and yet to finish when I’m talking about yet another. I always protest that it isn’t that I’ve forgotten, or abandoned those projects,  just that they are on a back burner, for rather a long time. But I do intend to swing around to them in good time. Sometimes this is due to monetary aspects of continuing a project. For instance my CNC router project. I started a long time ago, full of enthusiasm and built the physical gantry etc. But I didn’t get around to the electronics, mostly due to a lack of money to by the parts.

Some years ago I decided to build a pan and tilt webcam from scrap parts. as part of this I bought a bunch of electronics bits and pieces and got briefly into playing. But basically I built my single project, using just barely enough knowledge to attach a parallel port to the logic pins of some darlington arrays, which in turn switched volatages around the input wires of a stepper motor (pan) and a worm drive (tilt). I cobbled it together, and for a while had fun remotely controlling the web cam in my lounge from the office.

Eventually the novelty wore off,the device got tidied away, and I had no other project in mind and so the electronics got packed away. I really didn’t learn that much, just a couple of simple things to make that specific project work. Since then I’ve done lots of workwork and woodturning projects, developed a mobile app, and I’m actually working on another now. But I always had it in mind to come back to electronics, maybe to meld together all these hobbies into some projects requiring a bit of everything.

But the problem is that if you don’t really know what you can do in an area, it is hard to envisage a project. When I watch stuff like the ben heck show, what is obvious is that he finds various projects easy, because he is just stitching together stuff he has lots of experience in. And so I decided that I should have some more directed learning and start playing with electronics to control motors/servos etc in some general ways. To build up a stock of components and experience so that I can open my mind to the possibilities of projects that would include these parts, just as I now have ideas that take turned components or need the bandsaw to make long straight cuts.

For christmas I asked for some components , a servo, a stepper motor, a stepper driver board etc, so now I have got the electronics out again. And so far what I’m realising is that I have no idea how electricity works in circuits. Well ok, that’s not strictly true. The problem is I’m pretty comfortable with a basic circuit, the kind that has a switch and a bulb, or a sensor and a buzzer. Where I get into trouble is with IC’s and servos, digital circuits that require pulse width modulation. I can go through some of the steps that I think *should* work. but when they don’t I lack the skills to figure out what is wrong. is the program totally wrong? is the circuit screwed up? Why do I get a voltage *here*? why does connecting +v *there* cause everything to stop? 

I’m pretty lucky in that I happen to have an old oscilloscope in the cupboard (now on the right side of my desk above), it has no probes but I’ve ordered some now. The next challenge will be to figure out how to work this machine, it looks somewhat more complicated than a multimeter…I hope I can figure it out and it becomes a useful tool in my arsenal. Not least because I’ve had the thing sat around for a long time since I was given it, and it has drawn the odd ‘why on earth..?’ comment. So it would be good to find it a useful place in my hobbies.

My biggest question right now, is where do I go to get the education I need? So far a lot of what I find is either so basic as to be trivial, or completely unexplained (just copy this circuit and don’t ask why this arrangementof resistors/capacitors/diodes is the right one). On the one hand there is something to be said for just learning by copying and hopefully picking up experience. I certainly don’t want to drown in hard core physics. However I do want to get a much better understanding of how these things work together in a digital electronics circuit. It would be a start if my obvservations of a circuit matched up with my expectations. At the moment I am perfectly capable of building a circuit I think should work and see it do nothing, and similarly to build a circuit that I would never have guessed would work but none-the-less observe operating.

If anyone reading this happens to have any recommendations on books/on line resources etc,  I would love to hear them. I am going to build at least some basic cnc machine. and I would like to really understand it, rather than just plug together big components like lego.

3 responses to “Learning electronics”

  1. Hey Dan – I’m doing something similar. I’ve had the ol’ Raspberry Pi on the shelf for a while without any sensible idea of a project to do. At Christmas I got a telescope, and I’m now coming up with a similar challenge – a “GoTo” mount for the telescope. I’ve done electronics at GCSE and forgotten more than I knew since. Let me know how you get on, and if you find some useful resources. I’d definitely scout round the R-PI/Arduino forums though, as a lot of people are now asking the same questions

    • Well hello there mr masters. It has been a while… I came to much the same conclusion, I bought myself an arduino and hadd aservo up and running in no time. also now have mystepper motor being driven jvia stepper driver board). next job is coupling the motors to some threaded rod…should be interesting

  2. Indeed – howdie! I picked up one of these to play with for the pi:http://www.ebay.com/itm/Step-your-Pi-Stepper-board-with-stepper-motor-for-your-Raspberry-Pi-/251218184781?pt=LH_DefaultDomain_0&hash=item3a7dc54a4d

    Tho it is from the U.S. so will take some time to arrive, but seemed a simpler start point. I think the prob with the stepper motor code is getting the timing right to switch the pulses, as otherwise you can get ahead of yourself.

    I’m going to do something similar – using some gears to spin the speed down – for the telescope mount, I’m happy to trade a bit of speed (within reason) for accuracy and torque anyway.