My plan is to make the RadioBoard to be real, look also VemsFrontier/Bluetooth
I got Volvo Amazon with B20.
I mounted a 36-1 toothwheel to crank from Ford (it's like [this]) and Honeywell GT101 hall sensor. I set air gap to 1.2mm, connected sensor to 9v battery and 10k pull-up resistor to output. When I manually rotate the engine dvm showed near 0v when tooth was near the sensor and 9v when no tooth, like it should. I even tried to rotate engine faster and I saw good pulsing with scope. I started the engine (currently coil trigger, v2 genboard) output was most of the time low. Frequency should have been ~600Hz idle but it was only ~60Hz or less! I tried to move sensor closer (much less than 1mm) to toothwheel and away from wheel 2mm or more. No help, signal was the same. So I moved sensor as far as about 4-5mm and it started to work! GT101 sensor specs says air gap 1.02-2.03mm. Now it's atleast double.
![[this]](http://www.bowler.fslife.co.uk/pressedtriggerwheels.jpg){kind=link}
I did try power sensor from adjustable power supply and also tried 1k pull-up resistor. Neither did help. Sensor is mounted so when no tooth it has no metal in front of it and when tooth is front of it metal is much over sensors centerline. Sensor has built in capacitor between vcc/gnd.
Why? Should I use it like it work (~4-5mm away from triggerwheel) or what should I do?
''It's hard to give advice in this matter, one thing is sure and that is that the trigger wheel is not suitable for a GT sensor. But I have used the GT sensor a lot and have used it far outside it's specifications with good and bad results. What I do know is that the sensor is self adjusting, you'll notice this if you put a piece of steel in front of it at 1mm distance and then move it to 7mm distance. It will go high for a while and then selfadjust to see the steel again
I think this is what happens with the trigger wheel you have, it sees the solid disk for some reason, probably because there is not enough material in the trigger teeth. Moving the sensor further from the solid disk in the axial direction (of the crank) could help.
I'm pretty anal about triggers and I can only advice you to make sure that it behaves predictable at all rpms before you start loading the engine. I have seen very expensive failures because of non consistent trigger arrangements.
If you choose to make a new trigger wheel you should know that the GT1 sensor does not work well with trigger made up of large raised areas with smaller lower areas as a trigger wheel made by drilling holes. This is because of the self adjusting feature.''