Various Circuits

This document is an introduction to the Wideband Fuel Mixture Display (FMD). We modified the original Silicon Chip Fuel Mixture Display (that used a narrowband sensor) for use as a display for the DIY-WB wideband oxygen sensor controller. After first publishing how to modify the Jaycar KC-5300, we got Jaycar to make up the kits for us and we called them the TE-5300 display. These units were quite successful but we wanted them to be easier to build, so we created the improved TE-5301 display...

This circuit has been designed to alert the vehicle driver that he/she has reached the maximum fixed speed limit (i.e. in a motorway). It eliminates the necessity of looking at the tachometer and to be distracted from driving. There is a strict relation between engine`s RPM and vehicle speed, so this device controls RPM, starting to beep and flashing a LED once per second, when maximum fixed speed is reached. Its outstanding feature lies in the fact that no connection is required from circuit to engine...