morris_marlin
Ignition Driver Box
While waiting for my megasquirt kit to arrive from the US, I started building the box of electronics to drive the individual ignition coils per spark plug (Coil on plug) used on the BMW M50 onwards engines. You can buy a 4 driver box from DIY AutoTune but it costs about $80 and I'd need 2 to cover the 6 cylinders.
Instead I've opted to build my own using the drivers from the original M54 ECU. Unfortunately they are in a TO-263/D2PAK surface mount package rather than the TO-220 BIP-373s that most of the Megasquirt builders use (but which would not be free). This makes soldering them up a bit more tricky in a DIY project. I'm not sure whether these are technically Darlington transistors or Insulated Gate Bipolar Transistors (IGBT).
I'm using some Veroboard with the copper traces removed in key places (like the back of the transistor where the tab is actually the source (12V) so it needs isolating. The transistors are hot glued to the Veroboard.
I'm using a 100 ohm resistor on the base of each transistor. I think the Megasquirt may already have 200ohms on each signal line so this may not be needed but it shouldn't cause a problem either.
The soldering is a bit messy but then it always tends to be on these prototype boards
Ignition Driver Box
While waiting for my megasquirt kit to arrive from the US, I started building the box of electronics to drive the individual ignition coils per spark plug (Coil on plug) used on the BMW M50 onwards engines. You can buy a 4 driver box from DIY AutoTune but it costs about $80 and I'd need 2 to cover the 6 cylinders.
Instead I've opted to build my own using the drivers from the original M54 ECU. Unfortunately they are in a TO-263/D2PAK surface mount package rather than the TO-220 BIP-373s that most of the Megasquirt builders use (but which would not be free). This makes soldering them up a bit more tricky in a DIY project. I'm not sure whether these are technically Darlington transistors or Insulated Gate Bipolar Transistors (IGBT).
I'm using some Veroboard with the copper traces removed in key places (like the back of the transistor where the tab is actually the source (12V) so it needs isolating. The transistors are hot glued to the Veroboard.
I'm using a 100 ohm resistor on the base of each transistor. I think the Megasquirt may already have 200ohms on each signal line so this may not be needed but it shouldn't cause a problem either.
The soldering is a bit messy but then it always tends to be on these prototype boards