speed controlled on/off signal

[mohmedhat]

do any one know if their is a wire or an ecu pin that produce a +ve or gnd signal when the vehicle reaches a specific speed? 40km/h 60km/h 80km/h or 100km/h????

i hava a lanos 1.6

Thank you.

[Daniel]

Seems to be something about this at chime bell level. However I don't know if this is a option or standard for specific counties. There is a unconnected input (pin 3 labeled "S") on my chime bell.

S.JPG

chime bell.JPG

schema.JPG

Doc hunter

[benzino]

Doc hunter

this!!

[mohmedhat]

do you think that the chime bell module determine the 120km/h speed from speedometer and then announce alarm? if so i will not be able to take a signal from it as it as you see alarm for many other things!!

if the ecu send the signal to the chime bell module at that speed on pin S then i can use this pin to drive what i need but seems the 1st scenario is the right one and then no use!!

[Daniel]

I really don't know how this works as it is not wired on my car. And there are probably more than one layout.

If I had to trigger something at a specific vehicle speed I would use a frequency-to-voltage converter like the LM331 feeded from speed sensor followed by a comparator like the LM311. This stuff has to be calibrated. That's the "old school".

Actually with a µcontroller and some lines of software you can certainly make the same function with less components. But this is beyond my knowledge.

[mohmedhat]

can you help me and post the circuit of that old school, i like it as also i'm an old electronics engineer, but i'm no longer working as an engineer!!

[Daniel]

This is a mix from IC's datasheets. The circuit is not tested but should work.

LM331 + LM311.JPG

Try it on a test board first.

board_test.jpg

You still have to calculte the resistor/capacitor values in order to reach your goal. Refer to included web links for more technical informations.

BTW I found in Leganza manual that the "chime module speed alarm" is triggered from dashboard speedo. So IMHO it's unlikely fitted on Lanos.

Chime Leganza.JPG

Have fun.

P.S. What do you plan to trigger at specific speeds? Back to the future?

[mohmedhat]

thank you very much for your valuable info

i'm planning to trigger door locks at 40km/h like oem and turn off my EHPS pump over 100km/h or 120km/h

[Daniel]

thank you very much for your valuable info

i'm planning to trigger door locks at 40km/h like oem and turn off my EHPS pump over 100km/h or 120km/h

Than you can fit a second LM311 on the same LM331 output.

[mohmedhat]

i'll try it, thank you very much for your kind support