Counting Pulses + Thermocouple Interfacing
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Posts: 46,084
Hi there,
I'm wondering if anyone has any ideas on how to count pulses, let me
explain. I am building an interative display for my car that uses a
character based LCD. The program is already datalogging some of the
engine's sensors via the ECU. However i want to remove my speedo
cluster on the car and replace it with my LCD. I can measure the
speed of the car no problem from the ECU directly but i need an
odometer to count up the mileage. My speed sensor sends out four
equally spaced pulses per tyre revolution, so a simple matter of
measuring the circumference of the tyre will work out the distance
travelled for every pulse.
Perhaps i will consider doing a speed/time thing - i already know the
speed of the vehicle, so if i measure that over a predetermined
period then i can get the distance it has travelled?
The question is, how to count the pulses from the speed sensor while
the program does all the other things it has to? It continually asks
the ECU for sensor data, formats it the displays it and so on many
times a second.
Also, does anyone know the best way of interfacing a thermocouple? So
far my searching the net has revealed a few IC's that will provide a
linear voltage output in relation to temp (and perform the
compensation that thermocouples need) which could be read by the ADC,
but is there anything out there that can interface with I2C for
example that would make things neater and save on adding lots of
extra components.
Any thoughts/ideas/comments would be greatly appreciated!
Thanks,
Mark.
I'm wondering if anyone has any ideas on how to count pulses, let me
explain. I am building an interative display for my car that uses a
character based LCD. The program is already datalogging some of the
engine's sensors via the ECU. However i want to remove my speedo
cluster on the car and replace it with my LCD. I can measure the
speed of the car no problem from the ECU directly but i need an
odometer to count up the mileage. My speed sensor sends out four
equally spaced pulses per tyre revolution, so a simple matter of
measuring the circumference of the tyre will work out the distance
travelled for every pulse.
Perhaps i will consider doing a speed/time thing - i already know the
speed of the vehicle, so if i measure that over a predetermined
period then i can get the distance it has travelled?
The question is, how to count the pulses from the speed sensor while
the program does all the other things it has to? It continually asks
the ECU for sensor data, formats it the displays it and so on many
times a second.
Also, does anyone know the best way of interfacing a thermocouple? So
far my searching the net has revealed a few IC's that will provide a
linear voltage output in relation to temp (and perform the
compensation that thermocouples need) which could be read by the ADC,
but is there anything out there that can interface with I2C for
example that would make things neater and save on adding lots of
extra components.
Any thoughts/ideas/comments would be greatly appreciated!
Thanks,
Mark.
Comments
state, and federal laws regarding tampering with a vehicle's odometer.
Instead of replacing your speedo cluster I would augment it, thereby
not taking the risk of breaking some obscure law.
--- In basicstamps@yahoogroups.com, "Mark Lamond" <lists@m...> wrote:
> Hi there,
> I'm wondering if anyone has any ideas on how to count pulses, let
me
> explain. I am building an interative display for my car that uses a
> character based LCD. The program is already datalogging some of the
> engine's sensors via the ECU. However i want to remove my speedo
> cluster on the car and replace it with my LCD. I can measure the
> speed of the car no problem from the ECU directly but i need an
> odometer to count up the mileage. My speed sensor sends out four
> equally spaced pulses per tyre revolution, so a simple matter of
> measuring the circumference of the tyre will work out the distance
> travelled for every pulse.
>
> Perhaps i will consider doing a speed/time thing - i already know
the
> speed of the vehicle, so if i measure that over a predetermined
> period then i can get the distance it has travelled?
>
> The question is, how to count the pulses from the speed sensor
while
> the program does all the other things it has to? It continually
asks
> the ECU for sensor data, formats it the displays it and so on many
> times a second.
>
> Also, does anyone know the best way of interfacing a thermocouple?
So
> far my searching the net has revealed a few IC's that will provide
a
> linear voltage output in relation to temp (and perform the
> compensation that thermocouples need) which could be read by the
ADC,
> but is there anything out there that can interface with I2C for
> example that would make things neater and save on adding lots of
> extra components.
>
> Any thoughts/ideas/comments would be greatly appreciated!
>
> Thanks,
>
> Mark.
> Also, does anyone know the best way of interfacing a thermocouple? So
> far my searching the net has revealed a few IC's that will provide a
> linear voltage output in relation to temp (and perform the
> compensation that thermocouples need) which could be read by the ADC,
> but is there anything out there that can interface with I2C for
> example that would make things neater and save on adding lots of extra
> components.
>
> Any thoughts/ideas/comments would be greatly appreciated!
>
> Thanks,
>
> Mark.
>
>
>
>
>
>
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>
>Also, does anyone know the best way of interfacing a thermocouple?
>
>
I use MAX 6675 and a BS2p to get exhaust temp on my 4-cylinder car.
Regards, Johan