I have programmed the OLED display and made a mount to go in the cab. Looks awsum! Made my own 32x32 pixel icons for 4WD, Diff Lock etc. Then managed to drop the OLED and it cracked agghhrrr! New one will be here in a few days. I will add pictures and code for anyone to use/modify.
In the meantime I made the custom exhaust smoke generator.
The process is simple using the same principle as vaping. A Japanese cotton wick soaks up vegetable glycerine. Voltage is applied across a coil. The heat burns the glycerine creates a smoke and the fan blows it up the exhaust. The small 30mm 5v DC fan will be speed controlled and the voltage to the coil will also be controlled. This will allow me to sync the exhaust with throttle or RPM. I could simple show smoke when 'engine' is under load. Looking forward to tuneing it.
I have noticed that when you apply to much voltage to the coil you can get too much smoke and it finds every leak possible in the box. I printed some seals for the lid and fan and it works a lot better but it will still back up through the fan. I think I will need a bigger fan possibly 12V if I want serious smoke but for now I am happy with performance. For example I can turn on coil at a reasonable voltage the smoke will stay in box. When I turn the fan on it puffs out the exhaust. Looks cool.
Vegetable glycerine is the base liquid for vaping so you could add flavourings. Strawberry smoke sounds a good idea. I wonder if I add black food colouring will the smoke be black? I doubt it but will try for extra realism.
I will mod it to have 2 more screws to hold lid on to keep pressure constant along seal and a tighter interference around the exhaust(hence the Heath Robinson cotton seal attempt).
I can also refill by syringing glycerine back down the exhaust (WIN!). A refill seems to last forever though.
If you apply around 5 volts it will create a jet engine noise and you can see flames inside but does not cause damage. Do not know how I know this.
overall success.
OLED update to follow.