OBD MPGuino gauge

[hbachus]

Neat project guys, thanks for your efforts.

I've created a Wikipedia entry for the project OBDuino - Wikipedia, the free encyclopedia.

[Magister]

Thanks, I was not expecting something like this!

[hbachus]

If you wanted to cater for a different user-group, you could easily add a Racing Performance screen with these metrics:
- 0 to 60 timer
- 1/4 and 1/8 Mile timers
- Real time “Boost” (Intake Manifold Pressure)
(see http://www.circuitcellar.com/microch...4_Abstract.pdf for a dsPIC & ELM327 based Racing Performance design)

Of course, we wouldn't recommend these being used on public roads!

[dcb]

Originally Posted by hbachus

Of course, we wouldn't recommend these being used on public roads!

lol, or anywhere else From an eco perspective I think someone needs to do a CDA calculator, as well as an attempt at a "most efficient" acceleration monitor.

[Magister]

Originally Posted by hbachus

If you wanted to cater for a different user-group, you could easily add a Racing Performance screen with these metrics:
- 0 to 60 timer
- 1/4 and 1/8 Mile timers

There is one in my version but it's "hidden"

[hbachus]

lol, I thought that might get a reaction on this site.

While I wouldn't be testing such a racing screen, I think there are benefits from making the device appeal to as wide an audience as possible without compromising the basic purpose.

But I would be fascinated to try out your "most efficient acceleration" mode, and I'd rate that highly as feature candy.

For flat ground and a specific vehicle, the most efficient acceleration should be a function of velocity that is fairly constant over other conditions. Once determined, you could compare current acceleration with optimal.

I think someone needs to do a CDA calculator

CdA = Cd (Drag coefficient Drag coefficient - Wikipedia, the free encyclopedia) * A (cross-sectional area)
= 2 * drag force / air density * velocity ^2

Ignoring drive train friction and variation in air density (varies with humidity, temperature and altitude), your main challenge will be determining the engine force on the vehicle. There are some simple OBD-based calculations out there that make bold assumptions to derive HP, but I suspect those assumptions are too coarse to support a CdA calculation.

[njakts]

Hi there!
found this obduino thing going and tought... I have a bluetooth OBD scanner with ELM327 chip. loking around shematics I connected ELM's 18 and 17 pins to Arduino Tx and Rx, but all I get is ISO9141 Init..... Failed.
i have not put it in car, just bench testing, could it be that it fails to connect because it is not connected to car? (Yes, I added +12v to OBD reader)
or it is not enough to just connect tx and rx?
I cannot add pictures
thanks

[daok]

Why does it requires to have a 2n3906 for the brigthness but not for the constrast (direct from the Arduino pin)?

[Magister]

This kind of LCD LED can take more than 100mA for brightness so it can not be driven directly by a pin. However the contrast draws almost nothing.

[daok]

Source code is missing serialWrite and serialRead function that are used in `iso_write_byte(unsigned char)' and in `iso_read_byte()'.

Is that normal?