Question: What was your favourite thing to make in electronics

Andrew Fensham-Smith answered on 23 Jun 2015:

I made lots of different things. I made small memory devices, switches, amplifiers, radio antennas and things like that. It was fun, but the digital parts worked better in my head because you can use something called Boolean algebra to work out what sort of chips you needed to put into a circuit. Boolean algebra works in much the same way as normal algebra, but the answer is only ever a zero or a one. You can use it to simplify complicated expressions that might take ten or twenty different chips, to only three or four using the basic rules. That was pretty fun!

In the end I tried to make a car door alarm which would detect when the door was opened, wait a certain period of time to be turned off, and if it wasn’t then it would start flashing and making noise. It was surprisingly hard because you needed something to detect light and know when enough light was shone onto it (analog input -> triggers below a certain threshold), trigger a timer (analog, need to adjust for a timer), ability to be turned off (via a switch using a digital circuit), and if not alarm (digital to another timer to flash an LED, and trigger a sound). It was actually pretty difficult, but I managed to get most of it working! Electronics is really great fun and if you ever have spare time I would definitely recommend doing some of it at school.