myFocuserPro2 my build and integration into NUC self-contained control

Astro-Geek · September 24, 2019

This is a follow up to my thread asking about Nema motor choice https://stargazerslounge.com/topic/341158-myfocuserpro2-stepper-motor-choice-again-sorry/

I'm grateful for all of the member's assistance in helping me resolve the teething troubles in getting it completed.

It's now fully working and I'm extremely happy with the result. Robert's very benevolent free source project works really well, and is very comprehensive, as all of the threads about it on here have shown.

I made quite a few small mistakes along the way, which I thought I'd publish on here, to possibly save anyone else having the same problems.

Here's the random notes I made as I went along:

use instructions from the more recent PDF, "LETS MAKE A DRV8825 HW203 FULL myFocuserPro2 Controller.pdf"
The 5v buzzer must be "continuous" type
add a 247k resistor to the red LED to dim it down
add a 10k linear pot to lcd screen backlight to control brightness
add a 4.7k resistor across jack socket tip and ring to get temp probe to work. (it's in the circuit diagram, but not clear in the schematics)
add the resetable polymer 3a fuse to the power on switch (not shown on vero schematic)
edit the Arduino IDE burner preferences with "Display Line Numbers" , "Save when verifying or uploading", "Show verbose output during Compilation"
in Arduino IDE programmer, select TOOLS>Processor>"old bootloader" (the default setting didn't work for me, so I found this in a Google search).
Locate the folder myFocuserPro2libraries, and in that folder There should be SIXTEEN folders, Bounce2,LCD5110_Basic, myAFMotor, myDallasTemperature, myDHT21, myEEPROM, myHalfStepper, myI2cKeypad, myIRRemote,myOLED, myQueue, myRotaryEncoder, myTFTv2, myUTFT, newliquidCrystal,OneWire
Move these folders to Documents\Arduino\libraries folder (for windows). Replace any existing folders or files.
Do not edit or replace any of these files. They have been edited and modified to use with the myFocuserPro firmware.
Edit the main myFP2_DRV8825_2**.INO file in accordance with the instructions within to enable the various add-ons you have fitted in your hardware build.
Then burn the firmware onto the Arduino

After I completed the build, I found that the RS232 connector cable that I had used between the controller and the Nema motor was too thin for the potential 2 amp current, so I changed it for a 4 core cable with 18 awg conductors.

The final hiccup was the issue that was quickly resolved with all the prompt help from here, namely the firmware release that I was using ( *****288), which had a few bugs in it, causing the steppers to run slowly and noisily. After advice from here I re-flashed the Arduino with ver 290, and all of the problems were resolved. The 27:1 geared Nema now completes a revolution in 20 seconds, (instead of nearly 2 minutes), the motors now give out a moderate hum, rather than a loud rattle.

I built the controller into a transparent-lidded waterproof project box to save cutting a hole for the LCD display.

I didn't like the idea of repeatedly using the built-in miniUSB socket on the Arduino board as the working connection to my PC, so I added a right-angle adapter and a miniUSB to USB-B panel mount socket adapter to bring it out to the case. https://www.amazon.co.uk/gp/product/B00S6GY0VU/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1

The controller now hangs via a velcro strap from my mount and is controlled by my dedicated "Astro" NUC pc, also attached to the mount with everything connected by short leads and powered by a 28 amp SLA battery pack in a waterproof food container.

It's therefore completely self-contained and I can run any Windows based AP or mount software from any PC in my house via Windows Remote Control.

I made the Nema motor attachment brackets modular, so that I could use either the non-geared or the 27:1 on any of my telescopes. I don't have to worry about limiting the travel, as they are all Crayford type friction, rather than racks, so there's no danger of mangling anything up !