Archive for February, 2015

Re-learning electronics – fun with ArduinoQ

10 Feb 2015

I’ve been playing with the Arduino a fair amount lately. The completed projects consisted of giving new life to (very old) devices – an antique radio, and antique mantle clock. I’m happy with the results, and have both at the operational level – but I think the best thing about the Arduino ecosystem is that I’ll probably never call them “done” – there will always be tweaks that can be made.

Along the way, though, I’ve re-learned a few things about electronics that I had managed to forget since taking electronics in high school with Mr (Ray!) Lundy. If you’re just getting into IoT (Internet of Things), this list may be useful to you!

In roughly chronological order:

  1. Invest in a minimum set of basic tools and equipment to remove the pain from your experimentation:
    1. Soldering iron. Not a soldering gun, even if you have one on hand. It doesn’t have to be hugely expensive, but you’ll never get the precision you need with the gun.
    2. An ohmmeter. Ensure you get one with a “Diode” setting (the symbol looks like this: -|<| –
    3. Mini needle-nose pliers. Good for getting in to tight places, but also to act as a heat sink when soldering, to prevent component damage
    4. mini diagonal cutters, to allow snipping off of the longer ends of wiring after soldering
    5. A “third hand” tool
    6. Some shrink tubing to cover connections in tight places. (If you get into it, consider buying a heat gun when on sale – you can often pick them up for < $10, and the result is prettier, faster, and easier than using a lighter)
    7. Some solid-core wire. A good source here, if you have connections, is the network cabling that is used in office buildings (the kind permanently installed, not the sort that connects your PC to the wall). It contains 4 pairs of colour coded individual wire. (Using coloured wire can save you tremendous amounts of time / effort as you are tracing circuits).
  2. Resistors lie! Don’t just believe the colour coding. A quick check with the ohmmeter prior to assembly can save a lot of circuit debugging effort later.
  3. eBay is your friend – but shop carefully
    • Do your research – sort by price (low to high), shipping included. Price varies widely
    • Don’t just go for cheapest price. Do your research. Ensure you can get the spec sheet for the compoenent. (knockoffs of arduinos can vary the chipsets in use – ensure you know what you’re getting)
    • Buy a spare or two. The first time you buy local to be able to finish a started project where you’ve killed a component, or it was faulty, you’ll pay for ALL the spares you ordered. Besides, having the components on hand is more likely to make you experiment “just because”.
  4. Get the circuit working on a breadboard before moving to prototype or final assembly (especially if doing dead bug assembly). Consider using a simulator first, if you’re new to the game.
  5. Get good at soldering (again?) before you start playing with the components. More specfically:
    1. Tin the components before you start to assemble them
    2. Keep the tip of your solder iron clean
    3. Don’t start soldering components circuit boards, transistors or IC’s until you can complete a solder connection in <1 second, with only the minimum amount of solder applied.
    4. Know when & how to use an alligator clip or the needle nose pliers as a heat sink when soldering
  6. Make it pretty. Just because you can – and it will reflect on you.
    1. Plan ahead – you can’t retrofit “pretty”
    2. Keep wires running between the same components similar lengths
    3. Tie wires together using small pieces of shrink wrap. Route them in ways that make sense.
    4. Invest in reasonable enclosures
  7. Document your project for when you come back to it. Ray Lundy used to suggest schematic & paper notes be put in the assembly. I now use cheap, old low-capacity SD cards which still allow me to save not only the most recent version of the code, but the whole history, and schematics, if applicable. For your schematics, the list of options is covered on the same simulator page noted above.

As a side note to all of the above, Ray Lundy had a unique approach to teaching electronics, whereby he taught us through the history of radio as we learned electronics. Soldering practice for its own sake, followed by building a crystal radio, upgrading it to be a single tube rabio, then multiple stages / tubes. We then transitioned the radio from tube to transistors, and on to IC’s – and then you got to work building the computers that were used in the schools computer labs.

At the time, the approach seemed dated (who needed to know how a tube radio worked, when there were almost no tube radios in use at that time?) However, I learned late in the process the real reasons for the approach: the Crystal radio  really just provided targeted soldering practice with hard to destroy components (too much heat can easily destroy electronic components. The tube radios taught us multi-stage electronics, but also taught us not to short out components. (The 350 volt power supplies for the tubes made for very dramatic sparks if you were careless).  Transistors taught us to be even more careful with soldering temperature, before we got to ICs, which were still fairly expensive.

Mr Lundy’s approach was actually largely cost driven, aimed at not letting stupidity or laziness burn through the departments budget. However, the approach he took (“history of radio”) was also equal justification, and a lot easier for the students to swallow.  I’ve been able to adopt a parallel approach in business a few times – and realized that I learned a lot more in Ray Lundy’s class than just electronics.

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