Multi-node CANbus: possibility of buying assembled boards

[LROBBINS]

As noted in another thread http://www.wheelchairdriver.com/board/viewtopic.php?f=2&t=8395, I am not setup to real-world test the analog version of the Roboteq script, and a couple people using analog connections have reported bugs in it. While I am attempting to squash them, doing this "long distance" is a frustrating task. I am also nervous about doing this because I consider the CAN implementation a much safer way to control a wheelchair, as well as having much simpler chair wiring. I don't want anyone to be hurt because of me.

The CANbus system does require a lot more electronics, including SMD soldering several circuit boards, and no one has yet said that they have tried to build one. I have therefore gotten a quote for commercial PCB assembly to see if I can encourage others to go CAN by reducing the amount of work needed.

The complete set of boards contains 4 CAN boards, 2 DC-DC converter boards that turn on when the CAN bus is live, 1 DC-DC converter board that handles ON/OFF/Sleep for the whole system (all quite small and moderate component density), and 2 different larger power distribution boards that handle Roboteq on/off, high-current relay, brakes, lights, current sensors, and two linear actuators. Even using an off-shore assembly house, PCB assembly is not inexpensive and I can not afford it unless there are others interested in covering the cost for several sets. Assembly of five sets would cost about $1,125 (U.S. dollars - $250 per set); somewhat less per set if more were ordered.

Do realize, that there would be other costs and plenty of work needed even with pre-assembled boards. But those costs and that work would be about the same as for an analog setup: joystick pot, contactor relay and current sensor breakout boards (optional) to mount on the power distribution boards, boxes, Arduino Nano-equivalent boards, display screen (if desired), internal wiring and connectors and so on. No long multi-conductor cables, however. If four or more people tell me that they are interested, I will go ahead and place an order and send out sets after I have wired and tested one system that I'd keep for myself.

Lastly, I have no experience laying out boards for production rather than hand assembly. If there are any volunteers, I would certainly appreciate having others look over my designs and suggest changes that might reduce cost or improve reliability or safety.

[Burgerman]

I am afraid its all way beyond me! Not even sure what half of those words mean! Its like trying to explain how the tv works to my mum.

[LROBBINS]

A summary:

If enough people (4 or more) want to shell out about $225 U.S. to build a CANbus system, I can have all of the circuit boards fully assembled. Most of the rest sort of explains why it's so expensive and what work and expense (about the same as for an analog system) would still be needed.

[sin85]

I am interested. I am sending your post to the person who is assisting me so, I will confirm once I get his response.

[stevelawiw]

Put me down for a set please