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n/a
DELETED (Inactive)
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 Posted - Jul 13 2004 : 06:18:08 AM
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Ok I am in need of some help, I have googled this for days trying to find out how to do it and no luck. I need a Circuit to control a Relay by voltage. I have a relay wired up to Nitrous silonoid, now when the coils are closed on the relay the Silonoid turns on. ok I need a circuit that would turn on the relay when its input sees 4.5-5 volts. I would like to make this adjustable.
Ok what I am doing is hooking up a Nitrous system in my car. The nitrous can not be injected into the engine whith out Being at Wide open Throttle, if it is injected sooner BAD THINGS HAPPEN. Since my car is EFI (electronic fuel injection) it uses a TPS (throttle poistion sensor) the sensor reads 4.5-5volts at Wide open Throttle. So this would allow me to make sure it I hit the nitrous button that the nitrous isn't injected until the circuit sees 4-5volt which is Wide open Throttle. I want it to be adjsutable because if the TPS goes bad a new one dosne't always have the exact range, hence adjustable form 4.5-5 volt adjustable.
any help appricated
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Jul 13 2004 : 08:57:13 AM
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Why not just add a microswitch at your throttle body? Easier and cheaper.
However, if you are dead set on the circuit, you will need to build a comparator. Any electronics text (or http://www.discovercircuits.com) will have multiple examples. Fairly simple, but all the "little things" such as providing a regulated power source, filtering interferance, preventing oscillation and physically making the device unbreakable will take considerable effort. Obviously, you DON'T want a circuit like this to start oscillating and trigger your relay unintentionally.
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n/a
DELETED (Inactive)
3 Posts |
Posted - Jul 13 2004 : 09:40:49 AM
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ok the micro switch method on a Fuel injected car has problems been through a few of them. Now I had some one tell me this
voltage reference (zener diode), a comparator (LM339/LM392), a transistor (PN2222), and a few resistors will work.
What is your opinion on this. The Nitrous system has a few failsafes like a RPM window Switch, and a Main Switch and a Activation Switch. This circuit is going to be the activation switch. SO I have to have the Main Switch on and the RPM Window switch has to be between 3200rpm-5500rpm before it will let the TPS WOT circuit I want to build before it allows the nitrous selinoids to open. At Wide open throttle my tps sensor measures 4.76 volts. so this is the value I want the circut to see before it completes the circuit. Now Throttle posistion sensors with the same part # very in the voltage at WOT. and by loosening and slightly roating the TPS I can actually cange the WOT Voltage just a little like 0.15 volt span. Yes Nitrous Oxide Systems, and Nitrous Express sell these but I Think I can make My own a lot Cheaper than $125
Thanks for the reply So where do I go from here
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TPS WOT SWITCH
