Trying an optical trigger now, followed instructions for Hall sensor on primary trigger as per manual.
Have some questions. Went to the local electronics store and picked up an OPB804 optical switch. Built it into this little circuit that I found on the internet
since I have no idea how to do it myself. It works fine on the bench, low reads .27v to gnd when the beam is not blocked and high is 5.09v to ground with the beam blocked. Hook it up to my v3.2 and I get from 3.6v to 4.6v => this confirms the agressive primary-trigger pullup inside your controller
- the input trigger signal line that goes into vems reads 5 V (to gnd) when it isnt attached to anything. Read above how the internal pullup can be measured
I have a feeling the 10k resister needs to go and I just spent all that time building, mounting and sealing it for nothing and need to throw it out and start again, anyone please confirm??
- the 1k resistor limits current (and therefore the outputted infrared light) of the LED. The LED would be damaged by directly connecting 5V to it. However, lower value like 270 Ohm or even 100 ohm (measuring current would be a good idea; or voltage over the LED / over the known resistor) would allow more (infrared) light and opening the phototransitor more => pulling the trigger lower (closer to GND).
- I bought another one and tried without the 10k resistor (=> only the pullup in the controller), makes no difference at all (voltage readings ? Is that still exactly 3.6V or now goes lower ?). Signal doesn't go low enough no matter what. If I disconnect the signal wire only and tap the bare wire together, I can get rpm readings.