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Topic: where to find ARudino programmer online service? (Read 1 time) previous topic - next topic

alz3abi

Hello,

Currently im working on one project and i have all hardwares ready but my weakness in the programming.

I just want to know if there is any website or anyone who can program for money.

im still learning C/C++ language but it will take time in order to able to write any code.

my project is very simple , few instruments and few functions.


nathancamp

The Gigs and Collaborations area of this forum are for that purpose.  I'll ask a moderator to move it to that section.

patduino

Hi alz3abi,

This is it.  Look for PM on the topic.

Pat.
There are 10 types of people in the world, those who understand binary, and those that don't.

Dougsauto

Hi All 

I am in need of the same thing programming is my weak point.need a tach/  speedo program using switec stepper motors.

HELP!!!!!!!!

Dougsauto

Bainesbunch

State you problem clearly, your deliverables and your timescale.

Perhaps someone might be able to give you an estimate of the cost then.

Cheers Pete.
EmbeddedAT .. From Concept to Prototype to Production
Electronics and firmware design and project mentoring
I do answer personal requests for help when accompanied with a PayPal receipt ;)

Dougsauto

Hi All

I an building an automotive instrument cluster. one speedometer one tachometer using a switec X25 instrument stepper motor, specs are.

•Axial Force Maximum: 150N
•Axial Pull Force Maximum: 100N
•Radial Force Maximum: 12N
•Rotation Angle Maximum: 315°
•Coil Resistance: 260 ohm
•General Tolerance: ± 0.1 / ± 5°
•Rotation Angle Maximum: ~315°
•600 steps per 'rotation' (315 degree rotation)
.voltage 5VDC
The project only requires 270 Degrees rotation

input signal on the speedometer is a 5 volt digital signal range from 0 to175HZ @120 MPH
input signal from the tachometer is an A/C sign wave from 0 to 2060 HZ 12000 RPM
upon powering up the gauge  the needles need to auto zero. in other words they need to swing up to slightly more than 600 steps to hit the internal motor stops. and count back 600 steps to bring the needle back to zero.
The stepper will be driven directly off the Arduino uno from what I have read here and from experimentation and testing, the motors draw less than the arduinos  max load.
If possible I would like to run both speedo and tach off the same Arduino if not possible then I can use 2 separate arduinos one for each gauge. I can handle all of the electronics and make any suggested changes  to them if needed.
If someone can help please let me know. I have no problem with paying for a good working code.

Thank You    Dougsauto


Bainesbunch

I am not sure about driving them directly there is an ideal continuous limit of 20ma per pin with a max surge of 40ma. Overall the Arduino can source a few ma (200) and sink a few more (400) but the overall max I would have though was below your required limit.That does also not take into account the stall current or the inrush. This is especially relevant if you consider that you are stalling the motors at the end of travel whilst you count up to 600 steps in order to calibrate them.

here is a good reference for you to follow http://playground.arduino.cc/Main/ArduinoPinCurrentLimitations

counting the pulses is not a difficult job but reacting to rapid changes will depend on the frequency of sampling.

You would be better off having some sort of limit stop at the beginning of travel so that the Arduino knows where the start position of the stepper is. It can then step towards the stop switch and set its zero point.

Feel free to send me an email to Peter@embeddedAT.com if you want to chat about this some more.

Cheers Pete.
EmbeddedAT .. From Concept to Prototype to Production
Electronics and firmware design and project mentoring
I do answer personal requests for help when accompanied with a PayPal receipt ;)

PaulMurrayCbr

#7
Jun 03, 2016, 08:40 am Last Edit: Jun 03, 2016, 08:46 am by PaulMurrayCbr
input signal on the speedometer is a 5 volt digital signal range from 0 to175HZ @120 MPH
input signal from the tachometer is an A/C sign wave from 0 to 2060 HZ 12000 RPM

upon powering up the gauge  the needles need to auto zero. in other words they need to swing up to slightly more than 600 steps to hit the internal motor stops. and count back 600 steps to bring the needle back to zero.

The stepper will be driven directly off the Arduino uno from what I have read here and from experimentation and testing, the motors draw less than the arduinos  max load.
You should not run a steeper directly off the arduino. The problem isn't the max load, the problem is back-emf from the coils as your sketch switches them. The spikes can fry your chip. Some mosfets or a darlington array chip will set you back only a few bucks.

The other diffuculty is that a (eg: unipolar) stepper needs four wires to drive it. So that's eight wires coming off your board. A stepper driver needs just two wires - one for step pulse and one for direction, and it akes care of the back EMF using its own internal circutry. Having said that, with the setup you have you have enough pins on (for instance) an uno, so no problem provided that you isolate somehow.

Main difficulty is with the sine wave off the tacho. You didn't say what it's electrical characteristics were. Perhaps it can go into something like a schmitt trigger to clean up the waveform. A bit of hardware like this will be much faster than having the arduino sample the input and attempt to debounce it.

2060 Hz may be pushing it a bit. Suck it and see. Maybe feeding the output from the trigger into a t-flipflop (or a short chain of them) might reduce this to something more manageable.

Another issue is that steppers aren't really all that fast. I had one and I found that if I stepped it more than once every 4ms, it would start to slip. A digital display really might be better, or a strip of LEDs. But, if it has to be steppers, then it has to be steppers.

Oh, and another issue is that the arduino clock - the resonator - can be off by 10%. Don't know what happens when you heat it up. You may need a trimpot somewhere to allow you to adjust the thing, and you'd want to check it's accuracy every now and again. Alternatively, someone may sell an arduino clone with a crystal rather than a resonator. A little more expensive, but micros() becomes far more accurate.

But all that aside, this sketch wouldn't be super difficult to write. The difficulties I have just listed are all hardware issues.

http://paulmurraycbr.github.io/ArduinoTheOOWay.html

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