Developing electric car interface based on Arduino.

[rechargecar]

Hello EVeryone,

We are hard at work (well, sort-of) designing an interface board specifically for those Electric car hackers out there. We felt that now was the time to reach out to the hardware hacker crowd to gather thoughts on the features of our board in order to make a great product. We've got some of the major aspects nailed down, but we could use another round of brainstorming.

A little background: It seems that there just aren't many good options for people who are building/converting their electric car when it comes to instrumentation. Sure, there are a few simple 2 line LCD displays that show battery voltages and current draw or whatever - but nothing is very customizable or good-looking. In addition, there are just so many different cars people are converting and manufacturers don't always use the same standards.

So, lets say for example that we want to get the original tachometer needle moving again after removing the engine from the car, calculate the vehicle speed knowing motor RPM and gear ratios, displaying on a nice big graphical LCD, and logging everything to an SD card. Or maybe, measure the current flow through a wire while keeping track of overall distance traveled using a GPS module and then calculating efficiency of the car in kW•h/mile and displaying that on a cool analog gauge.

How can we design a board that can do all of this and still be easy to set up and program - thats right, you guessed it: Arduino.

So here's the plan: the EVduino, Electricarduino, or...we will think of a better name than these I am sure.

- Based on Arduino MEGA board - plenty of I/Os, serial ports, etc.
- built-in OBD2/CAN interface to communicate with original car computer or new EV parts.
- designed to run off of raw 12 volts from car's electrical system.
- screw terminals for more secure connections,
- optical isolation on some/or all I/O lines.

- maybe some relays pre-installed.
- maybe a USB host port to talk to our other EV sensors via our "OpenAPI EV Management packet structure" as seen here: http://www.rechargecar.com/openness
- maybe a fancy enclosure to create a more durable and less interference-susceptible system.

I am sure that there are other features people might like to see (or not want to see). Any thoughts? We are all-ears.

Thanks!

RechargeCar team.

[rechargecar]

Time for an update and a few questions for the Arduino folks out there. We have a pretty good idea of the parts we will use and the schematic, but have run into somewhat of a fork in the road. Here goes:

Since we want to base our board on the new Arduino Mega 2560, we were initially planning on sticking pretty close to the original header pinout. The Mega pinout, however, shows the SPI signals on header pins # 51, 52, 53 while the corresponding UNO SPI pins are on 12, 11, 13.

Unless there is a good reason that the Mega SPI pins are moved, I think we will put them in the same place as the UNO. Doing so will hopefully allow for more shield compatibility with our board.

Any thoughts on this one? Thank you!

[rechargecar]

I just noticed that I wrote the wrong pin assignments above. It should be: 50, 51, 52, 53 on Mega corresponds to 12, 11, 13, 10 on UNO.

[rechargecar]

Just a quick update to mention that we are ready to release a schematic for our board, and can be found here:

http://www.rechargecar.com/macchina

Oh yea, we are going with name "Macchina", which translates to "machine" in Italian. It is also used as a slang word for "car".

[Richwest]

Good idea about the Electricarduino)) or maybe now it has another name..)) Luck!!

[Brastic]

I am working on the same thing. I found that the Arduino ran out of power to process that much information in real time. I would love to be proven wrong here, but for me it was just easier to step up to a more powerful ARM chip.