Believe it or not this is exactly what a large portion of our industrial metering was! You would take a voltmeter or an ammeter and then provide a scale plate labeled for whatever you were metering. Old school but it definitely works, and it is very simple.
Unfortunately both of the above kits drive the voltage output from within the gauge. It looks like the wideband sensors provide a 0.45V RAW output (from sensor to gauge), meaning if we just wanted to save some $$$ by buying the sensor for $45 we would have to develop a home-brew transducer to generate a usable voltage or current output (this voltage is too low for the PLC and most voltmeters to read). Or we could buy one kit, open up the gauge and see if we can reverse engineer it, it’s probably a pretty simple PCB. This could become a huge cost saver if we all start using them…Then I found this;
0-1V to 4-20ma converter schematic; (Feeds signal to PLC or other micro-controller)
Couple it with something like this; (provides a gauge for us humans to look at)
This site has several useful schematics for those with the skill/knowledge to build their own PCB’s. If we devoted the time to design the PCB there are many companies that will manufacture them for you at very low cost, sometimes less than $10 / PCB though they almost all have minimum runs. If there was significant interest in going this route, I might be willing to devote the time necessary to develop a master PCB for woodgas use - after all required and desired metering is determined (no sense in making multiple small PCB’s). I wouldn’t mind one that connected to all the sensors, probes, transducers etc and provided voltage outputs for gauges and 4-20ma outputs for automation, that would be pretty slick!
Although at $199 for the gauge, the sensor, the wiring harness, and the ability to drive a PLC (if desired) the AEM looks like a pretty decent value. Laziness is likely to get the best of me here!