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Topic: what input pin is it using? (Read 5813 times) previous topic - next topic

GoForSmoke

That first link --- anyone who pays that much for a Hall sensor has more money than knowledge. Holy cow, what a ripoff!

You have sensors in place though I'm not clear what you want the data for... is it to know speed?

Again, I would gather data and see which is suitable before even starting to design a final package.
Nick Gammon on multitasking Arduinos:
1) http://gammon.com.au/blink
2) http://gammon.com.au/serial
3) http://gammon.com.au/interrupts

Joes

ok then what sort of data should i be gathering?
like travelling down the road with one of the sensors connected to an oscilliscope? (which i dont have lol)

GoForSmoke

I would use an Arduino to read 1 sensor on 1 pin to maybe fill an array at the tap of a button with timestamps showing state change times **just to see if I get useful data**.

If I didn't have a laptop to save those to then maybe I'd have them go to SD or EEPROM for later retrieval. Perhaps I'd think of a way to get speedometer data in there or just write that on paper.

You could have it read a pin and light up one of a row of leds to show data within different ranges. You don't have to be exact, just look for a suitable match to what you need.

What have you tested already? Do you need more complete or better data?
What can I say? I still don't know what this is for anyway.
Nick Gammon on multitasking Arduinos:
1) http://gammon.com.au/blink
2) http://gammon.com.au/serial
3) http://gammon.com.au/interrupts

Joes

sounds like more code i dont understand, or know how to write lol currently havent done any testing but i do have a sensor and trigger wheel to play around with.
basically this is for a 4wd system in a car i have written a code already to control it manually but i want to now be able to conrtol it automatically so to look at the 2 rear wheel speeds and pick the fastest travelling one and compare it to the speed of the propshaft and if it is going slower execute it into another piece of code to lock the diff up.

PeterH


look at the 2 rear wheel speeds and pick the fastest travelling one and compare it to the speed of the propshaft and if it is going slower execute it into another piece of code to lock the diff up.


That seems unnecessarily complex. Unless your diff has broken you know that the propshaft speed is proportional to the average of the two wheel speeds so all you need to do is look at the ratio of the two wheel speeds.
I only provide help via the forum - please do not contact me for private consultancy.

GoForSmoke

If the car is not going in a straight line the outer wheel will turn faster than the inner wheel.

I have been assuming that you have done at least a few of the example projects that came with your IDE. They do require some hands-on to teach basics.

Suppose you hook up the sensor and wheel you have and see what you can get from that?
The sensor is digital right? It's either on or off, LOW or HIGH, 0 or 1?

So write code to read the sensor and if it is HIGH you turn a led on (UNO has built-in led on pin 13, I dunno about the MEGA) and if it is LOW you turn the led off. Then turn the wheel and see how the led flickers. If it does not then it's time to check the wiring and the code.

All that does is to ensure that you can read the sensor and get meaningful data.

Nick Gammon on multitasking Arduinos:
1) http://gammon.com.au/blink
2) http://gammon.com.au/serial
3) http://gammon.com.au/interrupts

Joes

Quote

That seems unnecessarily complex. Unless your diff has broken you know that the propshaft speed is proportional to the average of the two wheel speeds so all you need to do is look at the ratio of the two wheel speeds.


i disagree the car is normally a front wheel drive car, when slip is detected it will lock up the rear diff (as it doesnt have a centre diff) to transfer the power to the back wheels. in its original state the car will decide how much lock to put on by looking at the outside temperature, steering angles, throttle position, G force meter and overall speed. so this will be a simple system compared to the original

Quote
If the car is not going in a straight line the outer wheel will turn faster than the inner wheel.


yes it will this is why i want the arduino to pick the fastest moving wheel

Quote
I have been assuming that you have done at least a few of the example projects that came with your IDE. They do require some hands-on to teach basics.


yes i have so my knowlege is very limited


Quote
Suppose you hook up the sensor and wheel you have and see what you can get from that?
The sensor is digital right? It's either on or off, LOW or HIGH, 0 or 1?

So write code to read the sensor and if it is HIGH you turn a led on (UNO has built-in led on pin 13, I dunno about the MEGA) and if it is LOW you turn the led off. Then turn the wheel and see how the led flickers. If it does not then it's time to check the wiring and the code.


yes i would of thought so i will have to try that
but i am on the understanding that it is a hall sensor
i will do that and let you no what i get




GoForSmoke

Be aware that there is more than 1 kind of hall sensor. Some are digital switches (yours probably is) and some are analog sensors (that can be read digital too). All react to magnetic fields.

This is time to play and try different things to see what works and what comes out. You will gain knowledge that you can be sure of just by experimenting.

Be sure to put a resistor in the path between 5V to sensor to digital pin unless the sensor already has one. A 1k resistor should keep your Arduino pin safe, even 2.2k is not too much for digital.

Nick Gammon on multitasking Arduinos:
1) http://gammon.com.au/blink
2) http://gammon.com.au/serial
3) http://gammon.com.au/interrupts

Joes

Quote

Be sure to put a resistor in the path between 5V to sensor to digital pin unless the sensor already has one. A 1k resistor should keep your Arduino pin safe, even 2.2k is not too much for digital.


so i still need to put a pull down resistor to the digital pin?

Grumpy_Mike

Yes still have a resistor pulling in the opposite direction to the sensor.

There are in fact two types of digital hall sensor, one which switches when it sees any magnetic field and the other that outputs one state when it sees a south pole and changes state not when the magnet is removed but when it sees a north pole.

PeterH


i disagree the car is normally a front wheel drive car, when slip is detected it will lock up the rear diff (as it doesnt have a centre diff) to transfer the power to the back wheels. in its original state the car will decide how much lock to put on by looking at the outside temperature, steering angles, throttle position, G force meter and overall speed. so this will be a simple system compared to the original


For that to make sense, the drive to the rear wheels must be very different to a conventional prop shaft and diff. Do you have a clutch in the prop shaft? (I remember there was a very nice hydraulically controlled one from Land Rover a few years ago.)
I only provide help via the forum - please do not contact me for private consultancy.

GoForSmoke

Nick Gammon on multitasking Arduinos:
1) http://gammon.com.au/blink
2) http://gammon.com.au/serial
3) http://gammon.com.au/interrupts

Joes

Quote

For that to make sense, the drive to the rear wheels must be very different to a conventional prop shaft and diff. Do you have a clutch in the prop shaft? (I remember there was a very nice hydraulically controlled one from Land Rover a few years ago.)


yes it is a  hydraulically controlled


i tride that sensor out to day and could not get it to work the way we discussed so i tock the 10K pull down resister out and put a pot in then tork the pot down to 1.3k and it did work but very tempermental
the sensor seems to work between 1.0-1.3k
what do you think?

PeterH


i tride that sensor out to day and could not get it to work the way we discussed so i tock the 10K pull down resister out and put a pot in then tork the pot down to 1.3k and it did work but very tempermental
the sensor seems to work between 1.0-1.3k
what do you think?


I think you need to find out for certain what sort of sensor you have and what sort of signal it outputs. Is it definitely a Hall effect sensor? I would have thought that an MVR sensor was more likely.
I only provide help via the forum - please do not contact me for private consultancy.

GoForSmoke

If it's a Hall switch then you use it like a manual switch/button.
Nick Gammon on multitasking Arduinos:
1) http://gammon.com.au/blink
2) http://gammon.com.au/serial
3) http://gammon.com.au/interrupts

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