YARF - Yet Another Robo Focuser.

[NickK]

57 minutes ago, skybadger said:

The answer to this is to move the code for serial and stepper drives to an interrupt handler and just use the main loop to respond to flags set by the handler. Nothing kills code like a serial poll loop.

Mike

Indeed .. most of the timers libraries are poll driven.

I've also thought that the power being supplied is less than the rated current, looking at the DRV guide the full step uses a step between positions that are 70% of power. So for running at full step I can increase the current limit to fit the 670mA rating to 970mA. Micro stepping below full step means that for part of the stepping it will be running at 130%.

 

[NickK]

Ok, form the bottom up tracing of wires, rescrewing the wires into the connector blocks... and it's working flawlessly. I think one of the wires was very weekly connected/intermittent in it's connection resulting in bad stepping.

The new stepping is really good (works perfectly from the focus tool in INDI). And I'm not just going to try micro stepping.

Just goes to show.. sometimes it's not software..

EDIT... also interesting- think my M0 line is pooped some how but the arduino output for M0 reads 5V on the multimeter.. :

    // MODEx  Stepping

    // 2 1 0

    // L L L  Full - WORKS

    // L L H  1/2 - NotWorks

    // L H L  1/4 - WORKS

    // L H H  1/8 - NW

    // H L L  1/16 - WORKS

    // H L H  1/32 - NW

    // H H L  1/32 - WORKS

    // H H H  1/32 - NW

 

Low and behold.. when set to HHH, the multimeter onto the M0 pin on the DRV board is reading 0V not 5V..

[NickK]

So.. until I get a new soldering iron (the butane was escaping in the handle!!) the focuser does Full, 1/4, 1/16 and 1/32  That will do

Mental note to solder the wires instead of screw blocks so they're reliable.

 

[NickK]

Here's the arduino current sources - if you use then you accept all the risks and agree I can't be held responsible for any damage resulting from it's use.

Current Arduino sources.zip

On the indi side - just use the standard Moonlite driver.

The ":X" series of commands are debug commands I use on the arduino interface. ":XX#" gives a status report for example - the rest are fairly easy to understand from the source.

To change the speed - at the moment simply change the speed setting (M0,1,2) in the DRV8825 driver constructor.

The DRV will need to jump steps when changing micro stepping, so at the moment I've not made that a parameter system also for now the speed is also disabled (this just varies the rate of steps at the current micro stepping).

 

[NickK]

Running at Full stepping with 1000step setting in INDI.

I will have to adjust the INDI driver as it has a maximum of 65,535 steps at a time before you have to reset the counting.. With 1/32 stepping .. for each focuser rotation it would need 200*32*100 = 640,000 steps and there's something like 2.5 turns of the focuser for the ~80mm travel of the focuser (1.6M steps)..

 

[skybadger]

If I could get my lad off MY PC I could finish my own.....

 

[NickK]

14 hours ago, skybadger said:

If I could get my lad off MY PC I could finish my own.....

It's one of those things.. each time you use the scope it reminds you of the fact!

Should have a bit of time for some drilling and bolting to finish it this weekend.. but it's still down the long list of priorities!