@Hagbard (and others)
Okay, quick update, I've had a bit of time today as I'm officially off work with the dreaded C19, so I've been trying to take my mind off it by messing about with the M600 drive HMI / buttonset.
- Today, I received a cheapo Shimano button-set, it has some sort of DI2 chip on it, so although the build is good, I'd have to design a little circuit board to host the same type of buttons to use the mechanical assembly (pretty easy though). It's sealed quite well on the front, but was able to prise it out using a screwdriver to break the seal which is some sort of rubbery glue. It wasn't easy to get to that point though, but I think I can probably reassemble it (if needed). (see attachments for horrific disassembly pics!). It's not a dead-end, but the 3 button DI2 switches aren't a simple fix unfortunately (still can't source the giant ones in the UK)
- I've been working on the CANBUS side of things today too, I've got couple of these (
GitHub - Xinyuan-LilyGO/T-CAN485) and have connected one of them up between the 2 HIGO cables from AliExpress. Initially I found that the system would power up, but would report 0 for the battery voltage. Tried swapping CANH/CANL and removing/replacing GND wire. Finally googled what the M600 baud rate was for CAN bus and found it to be 250KBS. Now that I know I can insert a microprocessor on the CAN bus this will open up a few options. I think I'll put a webserver on the ESP/CAN board so I can decode the CAN messages (and send them), I've used this on several small work projects, so it will be fairly easy.
- Not done any further work on designing a new button-set for the DPC241.CAN, but testing on a breadboard proves it's just a simple bunch of switches so anyone can do that! I'd previously looked at the membrane switches too, but wasn't sure how good the "feel" would be on the bars (as an aside some people are using these on road bikes already for the shimano gear switching with DIx - which means some of the shimano stuff is simple buttons, just not the one I've got)
- I'm also in the process of rebuilding an Exposure Flex e-bike Light I fried by by dumping 12V at 5A (from a big buck converter) into it without current limiting (oops), this is kind of relevant as, the remote driver board I'm designing will have an ESP32 to generate a PWM signal to dim the lights via the new current limited DC/DC run off the bike battery. It might make sense if I can use the CAN bus connection to get the speed sensor data to detect movement rather than the accelerometer that I was originally planning on using. I've actually got a usable breadboarded circuit for this project, but there are a few outstanding issues (powering the microprocessor for one), I haven't added CAN bus to this one yet though as it's just a standard ESP32.
So basically I'm working on 3 different things at once and some are closer than others, I'm thinking I need to start putting it all on my github now or it's going to get out of control. Not sure how I version control PCB designs though other than just dumping the KICAD project files into the repo though!
I'm also thinking that I can merge the HMI and the lighting project too if I can get the CAN working on a standard ESP32. It needs to be small enough to go in the frame with the DCDC though so the LILYGO board is a not viable as it's huge.
All good fun though :-D
, wheel size and circumference.
