WC CANbus controller - DRIVE link for updated files

[LROBBINS]

https://drive.google.com/drive/folders/1_QQ2pZCYo1F33Sd2r2hTI_nl8Y4Gg3ca?usp=sharing

[Arima]

Lenny, I wanted to let you know my package arrived a few days ago.

[slomobile]

Is there a BOM for all the parts we still need to source and install?
I'm having a heck of a time deciphering the notation on some components.
for example one off the power dist board has a diode symbol but labeled bid TV6 CR3 I'm guessing that is a Transient Voltage Supression diode, but I know nothing of the specs it needs or how it is supposed to be connected off board and I assume you already selected an exact part.

I know we need to find a 120x160 screen but no idea what the other specs are to have it work with the firmware. Found several 128x160.
I can't find the exact contactor but there are several very close. Are there any specific features it needs to have?
Brass board terminals?
6 Arduino Nanos. Does it matter if they have the FTDI chip or the CH340?
Anything else? Current sensors?

Maybe those of us with boards to finish can put together a group buy of the remaining components plus some spares.

Looks like this can't go on the 48v+ machine. Thats OK. I found a local metal artist that wants to help build a motorized frame runner and this will fit right in with its uniqueness.

[LROBBINS]

Hi Slomobile,

I do have a formal BOM for what is installed on the boards, but not for the other bits and pieces. I do have a series of QuattroPro spreadsheets with all that info, but would have to find time to look through them to see which one(s) done over the years are most complete and up to date. However, the specs are all (or most all) actually in the DesignSpark files so you might want to register for a free license from RS components so you can look at what's in them. By selecting a component, (alt)(enter) will bring up a window with various tabs showing part designation, mfr part no, RS part no, specs, board location and so on. The information probably isn't complete for every last one of them, but it is mostly there.

Now to some of your specific questions:

(1) The TVS shown on some drawings as "off board" were stupidly moved onto the current Power Distribution Sub board designed. Not only are they mounted on the wrong side of the board, the are also connected in a way that does absolutely nothing at all - they are connected across the current sensor shunts instead of being between the two leads of each motor. There is no way to do that on board! So, you don't need to buy these, but to unsolder them from the boards and, if you do want to use them (which really is probably not needed), they should be wired into the motor cables or connectors. I use a hot air wand at 250o C to heat soak them and a chisel tip at 360o C on the pads to remove them. The Roboteq motor outputs seem to already have pretty robust transient protection without them.

(2) TFT screen. I've used a couple different TFT breakout boards over the years. The ones that had micro SD card slots are no longer available, but there are many offers of ones with full size SD sockets. The last ones I bought were these:
https://it.aliexpress.com/item/32841982669.html?spm=a2g0o.order_list.order_list_main.230.4a2a3696AzHVQ2&gatewayAdapt=glo2ita
Any of these cheap boards will do and they seem to be electronically identical. Which you use depends more on what you chose as a box to hold it than anything else. Same for the RTC; any board with a DS3231 is OK.

Most all of the backlights on any of these boards draw too much current to connect directly to an Arduino pin. They can be directly powered from 5V, but because I want it to dim when the controller goes into sleep mode, I added a single transistor + resistor as described in the manual so that it can be PWM controlled from the Nano.

(3) Nano. The only Nano clones that ever gave me problems had a Promixis chip. The FTDI is OK (if genuine) as is the CH340. I buy them 10 at a time on AliExpress. For example: https://it.aliexpress.com/item/1005003441322318.html?spm=a2g0o.order_list.order_list_main.134.4a2a3696AzHVQ2&gatewayAdapt=glo2ita. They are now available with miniUSB (like the original Nano), microUSB or USB-C connectors so shop with a bit of care for whichever you want.

(4) These boards can be used with >24V motors. Take a look at the PowerDistribution Main board and you will see a couple pads marked for a jumper if running at 24V, or for attaching a DC-DC converter with 24V output if B+ is over 24V. That converter is need to supply the Recom DC-DC converter that powers the Nanos and CAN bus, and for power to light, actuators and brakes, contactor relay coil etc. while allowing higher to go to the Roboteq (via the high current contactor).

The only expensive component that's you need to add is that high current relay, which I bought from Mouser. RS has a better price but a 60 unit minimum order. Everything else was bought at AliExpress. Of course, boxes can add up too.

BTW - I did add a battery current sensor so I can integrate drain and know how much I've discharged the battery. In typical Lenny fashion, however, on one of my two units I left the controller powered while mounting the sensor and managed to drop the board shorting 24V to the 5V net, destroying the Aux Nano, the Aux2 Nano, two CAN boards and three current sensors. I've spend a lot of the last few weeks (when not going back and forth to doctors & hospitals with Rachi) figuring out all that was damaged and doing the repairs, in some cases more than once because I hadn't found all the failure points before powering up again. I've gotten pretty good at using a diamond blade to cut off ruined boards then using solder wick to clean header pins to mount new ones. (Yes, at the cost of much space and reduced reliability, at least when I don't screw things up myself, these boards can be mounted with male/female headers rather than soldered on. I don't recommend doing that, however, unless you use machined pin headers, or proper board-to-board connectors.)

Ciao,
Lenny

[LROBBINS]

I left out an answer to one of your questions yesterday. Yes, I used brass hardware for the high current connections in the power distribution module. The nuts were soldered underneath the main board and to the terminals of the leads that connect to the sub board. The nuts were soldered using stainless bolts to hold them tight, those were replaced with the brass bolts which were then ground down t the height of the nuts so there's a nice air space between the hardware on the two boards. I'm quite sure that stainless hardware would be more than conductive enough, but I find it handy to have the nuts soldered in place in any case. You may have some difficulty finding brass metric nuts and bolts locally, but there's no lack of sellers on AliExpress.

[LROBBINS]

IMPORTANT REVISION

Here's a fresh link for a new Drive upload of the files. This release of the "CANbus WC controller" includes substantial revisions of the Software and the Manual, and minor circuit board revisions. Do not "mix and match" these with earlier versions (including the Arduino Library files)!

https://drive.google.com/drive/folders/1_QQ2pZCYo1F33Sd2r2hTI_nl8Y4Gg3ca?usp=drive_link

This version includes the option of a third Allegro current sensor to more accurately monitor battery charge state, and has moved some procedures from Main to Aux modules thus distributing the computational load among the modules. The Programmer software has also been revised to take this into account.