OBD MPGuino gauge

[zwoodward]

I had been wondering about the display myself. Is it possible to use these devices with a vacuum flourescent display? I have read that they are bright enough and have a much higher contrast than LCD.
Thanks,
Zac

[cmags]

Originally Posted by zwoodward

I had been wondering about the display myself. Is it possible to use these devices with a vacuum flourescent display? I have read that they are bright enough and have a much higher contrast than LCD.
Thanks,
Zac

The OBDuino and MPGuino are both coded specifically for Hitachi HD44780 LCD displays. I know that some OLED displays are built with the same controller, and should in theory work. If the VFD comes with the same controller, its probably good as well. However, I can say that the timing does seem to be a little touchy. I had some other "equivalent" displays that just wouldn't stay running right and the issue wouldn't go away until I purchased the "official" LCD. Definitely at your own risk, but if you have a HD44780 equivalent controller, then you should be good to try it out.

[Magister]

Guys, FYI, as the ELM327 cost $32+sh (about $40 ) and we use only the CAN properties of it (ISO can be done with the freescale chio, VPW/PWM can be done with transistors or even an ELM320/322), I plan to use a CAN interface made by microchip, their MCP2515 and MCP2551, and use a CAN library to handle messages, and put some logic inside the AVR instead of the ELM's PIC.

This would reduce the cost of the OBDuino to a *duino board, an LCD, and a few components, about $40 all in all.

This is also because on a new prototype board, I think I burnt the CAN input of my ELM327 chip

[tangomar]

Magister,

in case of an ISO9141 OBD only car, what would be the total price of the OBDuino?

Another question: is there a permalink for this project or everything is contained in this thread?

Thanks

[Magister]

I guess about $40, let's say $20 for the *duino, $10 for LCD, $10 in various components.

A lot of info are in the project wiki page:
OBDuino - opengauge - Google Code - OBDuino Description

[tangomar]

Thanks. Sounds like a great deal.
Is it possible to display the amount of gas used during a trip? Sometimes I try to understand if it is better to go one way rather than another but they can have different length, speed, stop&go.

[cmags]

Originally Posted by tangomar

Thanks. Sounds like a great deal.
Is it possible to display the amount of gas used during a trip? Sometimes I try to understand if it is better to go one way rather than another but they can have different length, speed, stop&go.

Yes, there is a trip setting. If you want to use the trip to track your tank, you will need to leave constant power to the 'duino. It does turn off the LCD after a timeout, and doesn't draw too much so you should be ok. You can reset the trip with a middle+left combination, and then confirm. It should track at least distance and average MPG for that trip. Check the wiki for more info.

[Magister]

When you shutdown the engine, the OBDuino detect it and save trip info in EEPROM, you can then switch off the board by unplugging it or put a switch on the +12V as I did.

There is 2 trips, one is used for tank and the other as a normal trip. Both can be monitored for fuel consumption, distance, fuel taken. For the tank trip it can also display the remaining distance you can drive on your tank.

[cmags]

Originally Posted by Magister

When you shutdown the engine, the OBDuino detect it and save trip info in EEPROM, you can then switch off the board by unplugging it or put a switch on the +12V as I did.

There is 2 trips, one is used for tank and the other as a normal trip. Both can be monitored for fuel consumption, distance, fuel taken. For the tank trip it can also display the remaining distance you can drive on your tank.

Oh really? That's awesome on all counts! I like having a trip and tank tracking on my MPGuino but was willing to give it up because of some of the direct VSS pulse capture issues I'm having. I had also been pushing to recode so that the MPGuino would save the values to ROM so we can wire to ACC so as not to have constant on to save values. I guess we lose the capability of tracking EOC, but that's fine by me. I hardly ever do that anyway.

Out of curiosity, how do you check for engine shutdown? It won't confuse a DFCO as a shutdown, correct?

[Magister]

If the engine RPM goes from a positive value to zero, I save trip info in EEPROM