Jeri Ellesworth reckons the secret to learning electronics is to fail and fail often. Here are a few things we do to make it safer for kids to noodle around electronics on their own.
Electronics need power. Young kids often have difficulty spotting danger or seeing that one thing is dangerous, whereas another (apparently) similar thing isn’t. Our rule here is batteries and no AC mains power (unless an adult checks it and plugs it in).
We use battery connectors to tilt the playing field in the direction of success, so that “if you can plug it in, it’s ok”. For example, since 2.1mm barrel jacks are the standard for Arduino power, we use these on 9 volt NiMH battery holders. Some items like the Adafruit Arduino motor shield we use requires additional external power. The power connector isn’t polarised, so we permanently wire a barrel jack to it, to avoid accidents.
There’s a good range of polarised connectors available that you can use.
6 volt and 3 volt AA-size battery packs are good power sources for experimenting on a breadboard. NiMH rechargeable’s can deliver destructive amounts of current if shorted. Alkalines cells, which have much higher internal resistance, are more tolerant of mistakes. Large-sized EZ Hook test clips are great for ad-hoc connections to components or breadboarded circuits. They clip on securely and the connectors retract into the plastic body of the clip when not in use, making shorts less likely.
For digital stuff, pick a voltage for the logic levels, probably 5V is best. You can use level-shifting breakouts to hide the 3.3V components.
- Component leads tend to fly when clipping them after soldering to a circuit board. Safety glasses cover this.
- Burns. The best way to prevent this is a clear work area and a stand for the soldering iron. But fingers will get burnt, so make sure the solderer knows the drill. Ice cubes in a plastic bag, plus a splash of water to improve conduction between the ice and the fingers. Get the ice on as fast as you can and chill for 20 mins. Don’t skimp on the chilling time as it really helps healing.
- Lead-free solder. The consensus of OSH material I’ve read is that lead solder isn’t really a personal risk, but more of an environmental issue. Our approach here is hands wash with soap after electronics and no food in the work area. Lead-free solder is available if you prefer, but for beginners, keep in mind that lead-free solder needs more care and skill to get good joints. Also for lead-free soldering you really need a proper temperature controlled soldering station.
- Solder flux smoke. OSH advice is that you shouldn’t breathe this! It’s generally not healthy and some people can become allergic to the smoke. You can buy or build an extractor to suck the smoke away from the work area, ether outside or into a filter. We use a Hakko desktop unit, but you could get some of the activated charcoal filters and build an extractor with some computer fans.