Nice sitting down/post Christmas relaxing sort of project - playing with some parts to build a Wideband Lambda gauge/real time readout on the lambda sensor.
Inspired by the work of Jonas Bylund:
I'm making some modifications so my gauge will be a bar-chart and fill from lean to rich - the same direction the emerald software does and because it will give a visual representation of fuelling - more lights = more fuel. The gauge takes the 0-5v feed from the Wideband sensor and is just a calibrated volt meter to show a central 2.5v of that range.
Knocked up the simple circuit based on 3x LM3914 which do all the work, requiring only few external trims, resistors and a pullup system on the LEDs to make the display work in reverse.
Oldschool transfer to a veroboard layout using TinyCAD and VeeCAD - all free! Half the fun with vero is trying to get that optimal layout.
...mocked up part of the circuit to check operation.
This should give me a reasonably accurate 0.1AFR per LED across 30 LEDs - 12.6-15.5 AFR- either in the tested pre-formed units or an array which will let me hi-light specific values with different colours.