locked Re: Raspberry Pi

Vince White


I have been using a RPI4 to control a PMC-Eight for a while now.  You can do both serial or Wifi, however, I had issues with the RPI4 onboard Wifi not reliably connecting to the PMC-Eight, which was resolved when I used a Panda mini wireless N USB adapter (which is supported on the RPI4 Raspberry PI OS, so its truly plug-and-play).  To use the RPI4 to control the PMC-Eight via USB-Serial adapter, you'll need to buy and FTDI chip-set adapter cable and use the invert the DTR signal as described here.  To upgrade the PMC-Eight firmware, you'll need to use Windows and the PMC8Configuration Manager utility and you can also use this utility to easily switch between Serial and Wifi - I wouldn't recommend trying to do it by the command line.

Regarding whether to use VNC or not, the RPI4 is powerful enough to run KStars, INDI, EKOS locally, which is a benefit as you can do everything locally near the telescope and not need a computer tethered nearby.  Then you can VNC using a laptop or a VNC app on you cellphone.  I typically use the VNC app when initially adjusting my system and it is very convenient.  Check out the Astroberry project if you haven't yet, as it bundles everything nicely and is a good starting point.

One other comment is that RPI4 SD card interface is still fairly slow.  It takes a bit of effort to do, but I don't use the SD card at all on the RPI4 and instead boot/run off of an older Samsung EVO MSATA SSD with a USB 3.0 adapter - which is MUCH faster than using the SD card.  Only certain USB to SATA adapters work well with the RPI4, I'm currently using this one.  I'm also using this USB AC1200 wifi adapter with external antenna to get better Wifi reception since I have my RPI4 in a metal case, however, to use that adapter, you have to compile and install the kernel drivers yourself, which is complicated.  However, having both the external AC1200 Wifi and the SATA SSD lets me quicly transfer astro-photos to my main computer for post-processing at 15 - 20MB/s.  This also gives me a reliable connection to VNC to the RPI4, again, I was also having Wifi reception issues with the RPI4 in a metal case.


Mount: ES PMC-8 EXOS2-GT
Scopes: BRESSER 208mm f/3.9 Newt + ES HR Coma Corrector, Celestron C90 Mak, generic 50/191mm guide scope
Cameras:  Canon EOS RP, T7C (ZWO ASI120MC clone)
Misc: 2" Optolong L-eNhance filter, 2" Optolong UHC filter, Raspberry PI 4
Software: INDI + Kstars + EKOS, DeepSkyStacker, GIMP, Lightroom, Photoshop, SIRIL

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