DIY automatic start/stop

[Daox]

Thanks. You are correct, the arduino can put out 20ma per pin.

The reed relay I'm using for the crank signal runs @ 10ma, so the arduino should be safe.

I'll put in my order today for the bc546 and fast recovery diodes today then.

[Daox]

Hmmm, I saw a problem while putting together the order. The relay coil looks like it'll draw ~175mA, and the BC546 is only capable of handling 100mA.

[Daox]

How about this transistor?

KSC2328AOTA Fairchild Semiconductor Bipolar Small Signal

[groar]

Daox, such a great project

As saand noticed, if the photo-resistor doesn't receive light anymore then the engine stops. I can't imagine such an event on highway or in heavy traffic. Even for myself I would prefer a fail-safe approach, ie an engine that doesn't automatically stop by itself if the LED and/or the photo-resistor are broken.

Denis.

[Daox]

I do agree that that kind of failure would be bad. But, I also think its very unlikely that that part of the circuit will fail. Both items are solid state components and quite reliable. The other mechanical parts (relays) are much more likely to fail (and therefore have been chosen so that in such case they do fail in a way that does not affect normal operation). However, in order to make it even less likely to happen I will change things around a little bit. I'll increase the value of the resistor before the LED so that the LED is underpowered and should therefore last even longer than normal.

Also, in the event of any failure of the start/stop system, I have included a power switch to turn the circuit off and return the car completely to normal.

Unfortunatley, I haven't thought of any other way to easily impliment a fail safe neutral switch on a vehicle. I'm certainly no expert though and am all ears if anyone has another way of dealing with it.

[Daox]

I'm finally getting back to this project after finishing up my last arduino project. I've made a few tweaks to the circuit diagram with saand's help (which I don't have with me ATM), but I'll post it up soon as well as pictures of the rest of the progress. I have most of the circuit laid out on a board. For the most part, I just need to add jumpers to attach to the arduino, and then wire it up to the car. I'm sure it'll need some tweaking to work correctly, but hopfully thats not too far off.

[piers.singer]

Glad to see this project up and running again!

[Christ]

I don't know if this is useful information here...

My work van ('08 GMC Savanna) has an automatic starter relay that keeps the starter engaged with a tap of the key until the engine reaches a certain rpm, which means it's started.

[Daox]

As promised, here is the updated schematic.





Here is the board.

[Arragonis]

Did this get wired into a car ? I have a rumour of a company designing an add-in system for manual cars.