t vago's MPGuino workspace thread

[josemapiro]

That should be pretty complicated, but is in good hands, so it can only go right.

Thank you for your persistence, good job.
José Rodrigues

[tvcsantos]

Hi,

first of all i would like to thank once again for your efforts on providing support for the arduino 2560.

Yesterday, i was thinking that it would be neat to have mpguino reading data from sensors that are already available in my car, like oil pressure, oil temp, water temp, outside air temp, ...

I saw that this is not a strange topic for you and that you intend to do it sometime.

well i would like to play a bit with arduino and try to do this.

Since i'm not so good at electronics, and since mpguino already reads vss, i will take that things you be kind of similar for the rest?!, so maybe you could shed some light and tell me why do wee need to connect a 50k resistor to the vss followed by the 5.1V zener diode....

Thanks,
Tiago

[AndrzejM]

Originally Posted by tvcsantos

shed some light and tell me why do wee need to connect a 50k resistor to the vss followed by the 5.1V zener diode....

Thanks,
Tiago

Tiago,

VSS sensor is connected to ECU (in most cases) and to a speedometer, we don't want to alter these readings that's why 50k resistor comes in handy cutting the current it's second role is to secure Zener diode of excesive current. And the diode itself is to cut all the signals that are comming from VSS to Arduino's logics level (5V).

HTH

[tvcsantos]

Originally Posted by AndrzejM

Tiago,

VSS sensor is connected to ECU (in most cases) and to a speedometer, we don't want to alter these readings that's why 50k resistor comes in handy cutting the current it's second role is to secure Zener diode of excesive current. And the diode itself is to cut all the signals that are comming from VSS to Arduino's logics level (5V).

HTH

ok, but with that approach won't a miss some values of the VSS signal?

That is, suppose i get a 12v signal from VSS (that corresponds to some car reading) the zener cuts it to 5v ok... Now suppose that i get a 8v signal that is a different reading, then zener once again cuts it to 5v? So how I would be able to tell the difference from those 2 signals (maybe i'm understanding the all thing wrong :P)

Tiago

[AndrzejM]

Tiago,

VSS gives pulses only so it doesn't matter if these are at the level of 12V 8V 7V or any other untill these pulses are above 5V because that's what Arduino reads.

[tvcsantos]

Originally Posted by AndrzejM

Tiago,

VSS gives pulses only so it doesn't matter if these are at the level of 12V 8V 7V or any other untill these pulses are above 5V because that's what Arduino reads.

ah ok now i get it, we don't need to know the voltage, only if it is HIGH or LOW

[AndrzejM]

Exactly

[josemapiro]

Done 1000km without any problem, do not laugh just by now have done, but do not stray too with the car, which is good, because fuel prices in Portugal are very expensive, 1.7€ 1 liters of petrol and 1.6€ 1 liter of Diesel.
Still cannot understand me with the graphics, because I'm always in doubt about the way in which they are represented. If I could explain better how they work grateful.

Thank you
José Rodrigues

[t vago]

Made minor update to code, per request of josemapiro.

Added:

• Ability to select current trip reset upon wakeup due to running engine only, current trip reset upon wakeup due to button press only, current trip reset upon wakeup due to both running engine or button press, or disable current trip reset upon wakeup.

[amnonholland]

A warm thanks from Canberra, Australia to all those who have contributed to the mpguino project and in particular to tvago for the amount of time invested in developing this excellent tool!

A quick question for somebody with coding background - my mechanical engineering background does not help me here!

Im trying to write out a 0-5v signal on the UNO pwm pin with the fuel level to go to another ext gauge.

I have tried analogWrite(11, gallons()); after converting to integer ( int val = (int) gallons(); ?) but am not getting anywhere. Understand I need a low pass filter to convert to true analog. Im not really sure what variable i need to call up (which stores the tank remaining value) or where's best to put this line in the program (under mainloop?)

Any help would be appreciated. Thanks alot!