DoItYourself Engine Start Button with µProcessor control


Status: Ready (beta testing ongoing)


This project describes a small gadget which starts your Mini´s (or other car´s) engine by simply pushing a button (as like in most modern cars nowadays).
Other than the quick-and-dirty soloutions where you have to push and release the button until the engine has started, this button will take care of the engine start process automatically.





So here´s a short description what it does:

Starting point is when entering the car. My dasboard doesn´t have any controls left other than a 8 inch Touchscreen. By pressing the Start Button for at least 2,5 sec, ignition is turned on and the Touchscreen is lit. Short pressing the button in this state is simply ignored (safety related).

Another long press (2,5 sec) will turn off ignition again.

Any short press while ignition is on will initiate the engine start process. During this time the red ring around the Start Button is flashing and the Processor continously monitors the engine rpm. As soon the engine rpm exceed 500rpm, it is assumed the engine has started (this is subject to practical tests in some cars for confirming this is suffcien., In my Mini this stettings work excellent but can also easily amended by changing the source code).
In this case the starter motor is disengaged immediately.

Any press of the Start Button while the starter is engaged will stop the starter motor and put you back into the ignition-on state. If or some reason the engine should not exceed 500rpm within 5sec, the start process is stopped (safety related)and everything set back to the ignition-on state.

Once the motor has started and is running, any press of the Start Button will immediately stop the engine and switch of the ignition. As long the engine is running, the red ring around the Start Button is lit permanently. This makes it easy to locate it even it´s dark inside the car (safety related).

Summary of Features:
* Single Button operation
* µProcessor controlled
* Automatic Startermotor operation
* Numerous saftey features for safe operation
* Optional available with heavy alloy shift grip and heavy duty stainless steel push-button

Here you can see a video showing how to change between the different states.





And here some pics of the latest version. (PCB backside and mounted together with high power relay in enclosure.








 Here´s the schema of the final version (e) which is currently used in my car (November 2009). In the near future I´m going to offer either ready made electronics, professional PCBs and pre-programmed Processors, in case enough people are interested in having those.
A detailed installation instruction is subject to be drafted and will be available together with the hardware.






Beside the cables to an ordinary pushbutton, we need the following connections to the existing harness of the car:

12V - Brown - at steering column ignition loom connector
Ground - Black - at Instrument block multi connector
Crank - White/Red - at steering column ignition loom connector
RPM - White/Black - at instrument block, rev counter connector
AUX - Green/White - at steering column ignition loom connector
Ignition - White - at steering column ignition loom connector

I guess that´s about it!

You can order PCBs (18€ each, including programmed µProcessor already soldered) by writing me a mail.


Currently (05/2011)the program of the µP still seems imperfect. Either I will dig into it this summer, or someone with experience in Atmel Tiny 13 Assembler supports me in having a look at the processor source code