View Full Version : Fault box

10-07-2008, 03:18 AM
Good morning,
· So I have a project·that I am attempting to scale down in size.· The project is...the development of a tool that can be inserted within·an Engine wiring harness (specific circuits).· The purpose is to provide the capability to eliminate the operation of a sensor (three wire pressure sensor for example) and instead supply the ECU fixed readings that are outside what is considered normal operation.· This is a training tool that I'm trying to fabricate, one that would allow me to introduce:· open circuits, short circuits, low resistance within·circuits and high resistance within circuits.
· First, I simply installed some rocker switches to change one of the ECU sensor circuits from normal operation to "fault mode", I then used more rockers to alternate from open, to short, to low resistance and then high resistance.· However this of course is large and bulky.· I thought of instead using some NPN and PNP transistors to create "latching circuits" so as to operate each fault for a specified sensor and a rotary switch to select among sensor circuits, but this too seems overly complex.· I know that I can use a BS1 to take the place of the many transistors that I had considered using, but am unsure which way to go about it.·
· What I really need is a means to select one of four circuits and then introduce one of four states into that circuit.· i want to do this simply and cheaply, but I want to make sure it can perform all of the functions I require.

· Any recommendations?

10-07-2008, 03:33 AM
You have to take into account the voltage and current the sensors are passing before you decide to hook anything up to a stamp pin if you expect the stamp to continue working. For automobile engines you probably will still need to include transistors.

- Stephen

10-07-2008, 03:37 AM
All sensors for this application are operating on a 5 volt reference.· The pressure sensors are three wire (5v reference, signal and ground), the temperature sensors are two wires (signal and ground) using a pull up resistor within the ECU.· since these are not using anything higher than 5 volts I had assumed that the Basic stamp would be appropriate for my needs.