Adapting Lightspeed tach output for Vans Tach

[gmcjetpilot]

Walter that is a good idea just use the other MAG for your special SmartTach by DPS Instruments.

For those of you who want to try to drive the above tach by light speed here is a curicuit that might work. Have not tried it but it should turn the LS square wave from 0 to 10 volts to a inverted 0.7 volt (approx) to +5v saw tooth pulse.

The Lightspeed box outputs 4 10v 3.0ms pulses per RPM and the Vans Tachometer requires 8 pulses per RPM ( requires a 5v to 15v pulse signal).

rainsal, sorry it looks like your post was hijacked, but I don't know how to multiply pulses. I looked into the cool 555 IC chip, which I have used before. It takes a trigger and can put out any pulse you want. I can figure out how to take pulse out, but not add them. It's not impossible, just beyond my basic electronic skills, off the top of my head. I'll do some more checking if you want. Write me off line if you want me to check. My email is in my VAF profile. George

[rainsal]

Sorry i have not been on the forum for a while.... but i have solved the problem...... go to www.healtech-electronics.com they have a device called a speedo healer ...... adjust for 100% increase in pulses and add resistor (4.7k) between tach signal in and active on the speedohealer to excite the tacho itself & whammo it works!! I have basic wiring diagram as jpeg ... but do not know how to insert it into this response.

Many thanks for the responses:-)

BTW i notice that Deene Ogden has responded to this thread. Deen I have just finished building a DR107 ( c youtube.com/dr107egt) and have just got off the phone from James Courtney who has just finished reassembling your Green Machine and plans to have her airborne in the next few days:-) This will be the 5th Dr107 to fly in Australia ... many thanks!! R