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HEQ5 mods
Originally I modified this mount some time back with nema16 steppers and onstep, but lately I haven't been getting out to do anything due to the hassle of carrying everything out to the yard and the large number of cables and power cords I need to route and avoid tripping over.
I wanted to make something simple, with just one cable to plug in and also something I could pick up while assembled and move around, so my CGEM was out for that use case. I also thought it would be cool if I could squeeze the computer itself into the mount.
This is the first pass at that, its using an 8gb Pi 5 with the pimoroni nvme base and a 256gb nvme drive. Running the default Pi OS with kstars, phd2 and astap. I use tigerVNC to connect from my laptop or desktop via wireless.
Seems to work well enough to be usable, although I prefer Windows + NINA (I might see if a Radxa x4 fits since its an Intel based Pi format sbc).
The ribbon cable is the power and the UART connection to the Pi header, no USB adapter necessary. I also made a smaller version of the onstep MiniPCB and cut out all the auxiliary stuff I didn't need to make it easier to fit. It's not my design, I just took the onstep schematic and re-did it in kicad to remove everything that wasn't entirely necessary, shrink it down and got it made by jlcpcb once it was working.
The Pi power supply is a cheap buck converter from ali express, it claims 5v@5A but I've only measured 3A or so being drawn from it briefly. I have no suitable load to test it with right now and the Pi definitely complains at start up so according to the docs that will limit USB peripherals to 600ma. I think this may be related to not using USB-C with PD so the Pi doesn't actually know what is connected. I only have a guide camera (ZWO) drawing power from the Pi, the tests are with a Canon 60D on its own battery. Other than that its using a teensy 4.0 with onstepX and TMC5160s for the drivers. There is no web interface so for now the only way to configure it is with kstars/indi. The power supply is 24v@5A and is the only cable connected to the mount.
I'm also no designer so I built a model in fusion to fit the pi5 which is not all that pretty, but it fits quite well given I modeled it using photos of the original part set up as a canvas. The screw holes are about 1mm out and since it takes 10 hours to print I figured I'll wait until I make sure its a worthwhile exercise to make the change and reprint it.
Here's some pics and initial guiding data from the first tests. I was able to do pretty lengthy subs without much trouble (tested up to 300sec), but I didn't put a lot of effort into focusing and wasn't trying to capture any images. I haven't set up the flatener for this combo properly yet either.
I'm pretty happy so far, next step is to make some minor tweaks to align the case a bit better with the holes in the mount, and do a new belt drive cover with some cable management built into it.
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