2x2

Yeah so it just passes on each pulse from my hall sensor to the bikes until i reach 15 MPH then it switches to generating its own signal while I'm above 15 MPH. I have an alfine 8s which does automatic shifting (works really well... just amazing) it seems to shift based on a combo of cadence and speed so when speed was halved it would switch up due to high cadence and then down shift for low speed. So by keeping the real speed signal to 15 MPH it still functions properly as its normally in the highest gear by then or shift to it due to higher cadence. Would say that the mileage still wont be anywhere near correct in the long term, most of the time during my commute its reading 15 MPH while i'm actually doing closer to 30 MPH. It will be closer than halving the signal but at least with that you can double your reading to see how much you have done. i mainly just implemented it this way for the auto shift and possibility of user define speed thresholds.

ahhh knew there would be a simple solution, too used to doing everything in code. I was going to research it to get rid of the arduino but straight frequency division wasn't the answer for me. Thanks D8ve

Hey Festive Jelly, Just wanting to say thanks for your post, using your information provided i was able to build a similar set up to derestrict my Shimano Steps (E6001) powered bike. I opted for the arduino based approach as i wanted to clamp the detected speed just below the cutoff threshold instead of just halving the frequency to keep the DI2 automatic shifting on my bike. Build information to help anyone researching this. Bike: Merida Espresso 800 EQ Motor: Shimano Steps E6001 Parts used: - Arunino uno (plan on downsizing had a spare one) - Hall Sensor sheild https://www.jaycar.co.nz/arduino-compatible-hall-effect-sensor-module/p/XC4434 - Relay Sheild as electromagnet https://www.jaycar.co.nz/arduino-compatible-5v-relay-board/p/XC4419 [url=https://www.jaycar.co.nz/arduino-compatible-5v-relay-board/p/XC4419][/url] It was dead simple to put together just pull top of relay to get access to the electromagnet and remove relay contacts then just simply mount on top of existing sensor. Mount Hall senor and move existing magnet to trigger. For the Shimano Steps motor both the frequency divider method and the speed clamping derestricting method worked really well though with the frequency dividing my auto DI2 shifting bounced between gears endlessly. Placing the magnet on your crank does not work with the Steps motor and throws an error which is kind of annoying to clear. Just a quick question Doesn't using a flip flop instead of the arduino result in the magnet being on for one full revolution the off for one increasing your overall power consumption?