Sunday, July 29, 2012

50Hz everywhere!

I'm back! Wow it's been a while since i posted anything here. Mostly from being busy, then waiting for parts, then just plain forgetting to update this blog :S

Keeping the news short:
  • I've been able to set up a bigger workspace in the garage.
  • I applied for a mechatronics course and got into uni!!
  • I now own one shiny Mazda MX5! (too dark for pictures right now)

I tested a few different circuits to drive the fuel injectors and ignition coils. Back EMF turned out to be a major problem. I couldn't come up with a way to snub that voltage spike with what i had on hand, so i ended up with a bunch of dead power transistors. Below you can see what happens when i apply and remove power to the ignition coil. It's not a clean on/off because i was just touching the ends of wires together, so you get a switch bounce effect.
I've gotten my hands on some IGBT transistors that are specifically designed for this kind of application, but haven't had tried them out just yet.

Lastly, i've started moving everything onto a protoboard. I've had too many breadboard related problems. It's a real pain when i accidently tear out a bunch of connections while moving the board around. The worst problem is that it seems to act as an antenna for the 50Hz main supply. Even while on batteries it will pick up the signal if anywhere near a power point. 
So far the protoboard seems like a much better option. Also got rid of the intermittent connection issues with the dragon programmer i'm using.