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« on: March 15, 2011, 09:53:08 am »
Attached is a schematic diagram for a Universal Tachometer Adapter for Briggs Engines. The diagram is divided in to color coded sectional blocks for clarity.
This device takes the signal from the kill terminal on a Briggs Ignition and converts it to a signal usable by any known tachometer, including Automotive Tachometers, Equus Tachometers,
Digatron, Mychron, etc.
The output is jumper selectable for the above via JP1 and is also jumper selectable for either 5v TTL output, 12v pulse output, or Digatron "Open Collector Output".
This device uses an inexpensive ($2.95) Picaxe 08M microprocessor to do most of the work. This entire circuit will fit on a 1.5" X 2.0" proto board from Radio Shack.
The microprocessor is programmed via programming port J1 and a serial cable attached to your PC. The programming software is free from Rev-Ed. The serial programming cable costs about $7 or
you can make your own using an old serial mouse cable. Contact me for more info / instuctions.
The total cost to build this is about $20 assuming that you have a soldering iron, a volt meter and few basic hand tools. All of the components are available from either Radio Shack, Mouser, or
Spark Fun Electronics. I can supply a pre-programmed microprocessor at cost plus shipping for those who just want to make the board and not mess with programming.
It you have ever wanted to to get into electronics and / or embedded microprocessors this would be a great first project.
The programming code is attached in file TA_Code.txt I will be posting a 10 page DYI Instruction Manual on this in a few days.
Bill