Anybody DUE OTA with bluetooth or wifi?

Hardware Arduino Due
1

I've recently made an orrery (dynamic model of solar system) using a mega which I can upload sketches to with bluetooth and wifi. This is a requirement as the device is 3 metres off the floor. Sadly the processing power of the mega struggles to get all 9 stepper motors at full speed.

A due would solve my problems but I haven't managed to find a way of uploading sketches using OTA. I've scoured the forums but wanted to ask the question directly. I could consider using a second controller, even a rasberry pi if I had to, to upload the binary if there was a route in. The bigger boards are needed for the inputs, I need a few as there are seperate encoders and motors for each planet. Wires all over the place.

Any thoughts from the wise most welcome.

2

You're programming the Mega from the serial port, right? Doesn't the Due upload work the same way?

What software are you using to control the 9 steppers?

3

If you try the same with the DUE (OTA sketch upload) you also need to press the erase button at the same time, unless you have found a cunning workaround?
I'm using accelstepper to drive the motors, with half steps.

4

You mean OTA, or DFU? Do you know if it's "normal" that the Mega won't support so many steppers with that library?

5

The mega drives the 9 steppers quite happily, I have a custom board with 9 separate A4988 drivers. The motor speed is dependant on the number of pulses the arduino can generate in a given time. The motors all spin uniformly to begin with, but when one stops, the remaining motors spin slightly faster, then another one stops and they spin faster still.
I tried the DUE as it's an easy replacement on my board with the same footprint, and hey presto they all span at a much higher speed, with better acceleration and deceleration. The accel documentation suggests a limit of 10 stepper motors.

6

Not to put too fine a point on it, but is that possibly a side effect of the way you've utilized the library functions? Perhaps there is a way that doesn't behave that way?

7

I thought that myself, I've tried a number of different combinations of commands and always end up with the same answer. Whatever the limitation is, seems to be fixed when I replace the mega with the DUE. The mega is an 8 bit device while the DUE is 32. It does make sense that the mega just can't get enough pulses out to the 9 motors simultaneously.
I think another arduino, with a solenoid operated plunger, to push the "erase" button in, might work.

8

How would you put the code to run the 9 motors together? This is what I have...
{
mer.run();
ven.run();
ear.run();
mar.run();
jup.run();
sat.run();
ura.run();
nep.run();
plu.run();
}

9

Oh? That is your entire loop() function?

10

with this conditional code

while ( mer.distanceToGo()!=0
or ven.distanceToGo()!=0
or ear.distanceToGo()!=0
or mar.distanceToGo()!=0
or jup.distanceToGo()!=0
or sat.distanceToGo()!=0
or ura.distanceToGo()!=0
or nep.distanceToGo()!=0
or plu.distanceToGo()!=0
)

11

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