Ok, you will think that im a nerd after i ask this, but i swear im not, i just take on too many bets. ok, so my friend and i were betting that i couldnt make a gauge in my car to turn on when i hit 88 mph. like a flux capacitor gauge(note:Back to the future I,II,III) i was an idiot and told him i could do it. can i?? is there any way to make a guage that will turn on light a shift light, only for a certain mph??

 

you could go in and find out what voltage or ohmage(im not sure what the speedo works on) the speedo wire reads at 88mph, then splice into the wire and if its done by voltage, put enough resistors so no volts will get through until your at 88mph, and hook that to a little led......

it probably runs on volts, but if its on ohms then i really have no idea what to do.....

 

If it's ohms, then you'd do the same thing, using it as a potentiometer. Set yourself up a voltage divider.
You're not going to want to drive your light with that voltage though, better to put an opamp as a buffer/driver. Non inverting configuration. Or use a transistor as a switch to pass current through to the light.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jagan’92 &raquo;</TD></TR><TR><TD CLASS="quote">If it's ohms, then you'd do the same thing, using it as a potentiometer. Set yourself up a voltage divider.
You're not going to want to drive your light with that voltage though, better to put an opamp as a buffer/driver. Non inverting configuration. Or use a transistor as a switch to pass current through to the light.</TD></TR></TABLE>

wow....i dont understand most of that, but i sounds good to me

maybe explain a bit better, id like to know what it would look like, id like to know more electric stuff like this....