Now that's a support community! Thanks everyone!
I'll start researching some of the chips and solutions that you've all given me, and come back with some questions when I get myself a little deeper into this project. In the mean time, Let's see if I can fill in some blanks for some of the responses here:
60amp_relay wrote:Are you new to electronics? I couldn't tell from your post if you're just getting started, or an old hand,
Quite familiar with electronics, but just getting started with designing my own devices. But I like the idea of the bar graph proof of concept, that sounds like a good starting point.
esklar81 wrote:I suggest you have a look at Arduino
I have an Arduino dev kit on the bench, and it seemed to be "overkill" for the application to me. I was going to start there, but if there was a simpler approach then I would take a look at that.
esklar81 wrote:The only concern I have is: It's not obvious to me how (without external, durable memory) you could have the device remember the setpoints when it's powered down. Of course, if you're willing to re-set the setpoints about as frequently as you need to re-set the clock in the vehicle, you could just wire this to have power from the car battery at all times.
Good point, I'm not sure if that would make it a pain or not, but I would think I could solve this with a lithium backup battery on the board and some memory. It's something I need to look into as most of the newer "drive by wire" vehicles won't go to 100% until the ECU decides that's OK, so setting the high point can't happen in the driveway.
JonChandler wrote:This would be a simple project using either the free Amicus Compiler for a PIC18F25k20 or using free Swordfish Special Edition with a PIC18F2520 or similar chip with on-board EEPROM to store set points. Amicus and Swordfish are Basic compilers that are simple to use.
Either of these would be a great combination with the low-cost TAP-28 PIC application board. It's set up with dedicated connectors for real-world functions like reading analog sensors and sensors and connecting to display boards. The TAP-28 supports many PIC18F-series 28 pin parts.
Jon, thanks for these suggestions, I didn't have this route on my radar, until now...
thebecwar wrote:I'd also go to the SAE's electronics page and buy the OBD-II specification document. TPS is a code you can pull from the ECM, plus you don't have to tune the min/max values for each vehicle you want to use it on.
I started to wanter down the OBDII path, but there's a few challenges with it that make reading the raw voltage a better solution. Plus the response time of OBD can be an issue.
bill190 wrote:If you do want to go the OBD route, Microchip which makes Pic microcontrollers has a "CAN" topic on their forums
I'm very familiar CAN, use it almost everyday. The challenge here would be getting the CAN address for throttle position for each and every ECU out there. Not to mention that most of the manufacturers use 29bit CAN address format, which would take forever to crack. The OBD-CAN protocol that has become more common now, but it's not on motorcyles yet.