Three input OR alarm. 2 with 1.5volt on-state;1 with compar. output

[prosking1]

I need to disable a fuel solenoid on a diesel engine when one of 3 OR'd LED signals is in alarm.<br>1st monitored LED signal (oil pressure low).on state= 1.5vdc<br>2nd monitored LED signal (no alternator output). on state=1.3vdc<br>3rd signal is (coolant temperature). Must have add'l circuit to monitor for voltage drop across x-ducer and create alarm condition when voltage drop is less than 5.5volts dc.<br><br>Conditions:<br>1.Alarm signals may be from a flashing LED i.e.pulsing 1.5v state.<br>2.All LEDs must be OFF 1st before alarm circuit is enabled.<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Thanks to anyone who can help.<br><br>3.solenoid is 12vdc ~100mA.

 

it is a fairly straight forward one to sort if you can program&nbsp;&nbsp;a simple micro like a

 

[wzkbrown]

I can think of at lease 4 ways to do this.&nbsp;&nbsp;We first need to look at your requirements:<br>How much should the circuit cost? (nothing and as little as possible&nbsp;&nbsp;are not options)<br>How much have you to spend on doing the design?<br>Do you want a Hardware solution? - requirements are stable with time.&nbsp;&nbsp;Hardware is expensive to change but, in most cases less expensive to implement)<br>Do you want a Software based solution? - Requirements may change over time. (PIC, 8051, ***)<br>I will follow thread to see if I can help.<br><br>

 

You'll get an answer to your question at <A HREF="

http://www.smtnet.com.&nbsp"

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http://www.smtnet.com.&nbsp</A>;&nbsp;All

the heavy shooters are working at that forum and have been for at east 3 years.<br>Good Luck!