Possible Product: Engine Speed Switch

[Davemg]

Apart from other interests, I've been an amateur "electronics engineer" for a very long time. I've designed a small add-on box which monitors engine speed and switches outputs accordingly.

For example;

Engine not turning - no output
Engine turning but less than 400rpm (cranking or stalling) - one output is on
Engine turning at 800rpm or more - engine running output on
Engine turning at 1000rpm or more - engine properly running output on

This might be useful to operate Daytime Running Lights (coming on at 1000rpm and not going off until engine stopped), or disabling an Engine Start button once 800 rpm is reached.

I think this would cost about £20-£25 to sell and could use cheap relays to operate heavy loads (my unit would ground the relays) and would have volt free "contacts" to operate any other kit you might think of. I can easily change the rpm triggerpoints in software.

Interested in any applications, ideas, or if members think this is of interest - in other words, if you would buy one, then maybe it's worth me finishing a printed circuit board design.

Hopefully I've not posted this in a way which doesn't break the club rules

[greenwoo]

sounds clever, without being a techie - not sure what the practical application(s) would be?
If as i read the example it could be to conserve battery power (?) then having the lights switch off when at tickover might not be so handy if one's caught in a traffic jam at night.....

But as i said, i'm not a techie, so my imagination for the use is a bit narrow......

[b33fy]

Might be some mileage in developing it so the drls come in when the engine is running but dim when the sidelights are turned on. Could be the sidelights and drls are the same light unit so they could just dim when the sidelights come on. The Drls need to work only when the engine is running and the sidelights work with ignition off as well as all other positions. I use latching relays currently, though not very reliable

Hope that makes sense.

[Davemg]

Thanks all... I think the DRL switching is the obvious one, on at 1000rpm but not off again until under 400rpm (i.e.) you've stalled it or stopped. Dimming DRLs is possible in a couple of different ways and I hadn't thought of that; probably best dimmed using PWM (electronic control) which requires a software tweak.

Other ideas are

- cutting off a start pushbutton - I have one in the Quantum now with the Jaguar-style heartbeat (love that) all done in software; it cuts off/becomes inoperative when battery volts rise which is not always the best indicator of an engine running.

- change up lights, just a case of deciding what tripping points are required

- controlling auxiliary power sockets, so that they only run when the engine is over a certain speed. However, this works well in the Quantum with voltage sensing, I have it wired so running, say, a Coolbox will stop before the battery gets too low.

- silly now, but how about DRLs that change to red when you really put the hammer down

Just some thoughts and I have a test bed on wheels...