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Craig Shaw

Cheap DIY Raspberry Pi 3 SkyFi adapter with wifi hotspot.

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I have searched SGL for a tutorial incase this has been covered so forgive me if it has. I've also searched the web in general and couldn't find a full tutorial to do this, so i have collated a couple of tutorials that make it work.

I have managed to get SkySafari to work with a £32 ish Raspberry Pi3 and the cable that came with my scope with a usb to serial converter - the same things you need for connecting to a PC. It allows me to control the scope using the SkySafari Plus app on my tablet or phone AND it creates a wifi hotspot on the Raspberry Pi so it doesnt have to be on a network to work. This also turns the pi into a natty mini wireless router which is handy if you travel since it gives you a private wireless network when plugged into hotel wired internet ?

***STANDARD DISCLAIMER***

I AM NOT RESPONSIBLE FOR ANY DAMAGE THAT MAY OCCUR  TO YOUR HARDWARE BY FOLLOWING THIS POST OR ANYTHING LINKED TO THIS POST


It takes about 30 mins to do the tinkering, make sure you use the latest LITE version of raspbian.

You need:

  • Raspberry Pi 3
  • Portable power to it (preferably)
  • Raspbian Lite Image file
  • Appropriate cables to connect your Telescope to it via USB
  • Computer connected to network
  • Network cable to connect Raspberry Pi for initial setup
  • A GoTo / Push To etc telescope mount compatible with SkySafari Plus / Pro
  • A nice case for the Raspberry Pi


You need to know a little about accessing the Raspberry Pi by SSH.
For windows, use Win32 Disk Imager to burn the latest Raspbian LITE image to a micro sd card. Open the card on the pc (called boot) and make a blank file on it called 'ssh' - no file extension. This enables ssh access automatically.
Stick it in your Pi and plug it into your network router and a power source.
Find its ip address - i log into my router by typing its ip address into a web browser and look at connected devices, there are other methods though.

I use a program called Putty to ssh.

There are many tutorials on how to do the above and it isnt as hard as it first seems.

I used 2 tutorials to do this and i will link to them directly as the original authors explain it better than me. The first one is muuuch longer than the second which is just 3 steps so bare with it.

 

***NOTE***
When the first tutorial suggests a reboot after the upgrade, DO IT! Then ssh back into the Pi and continue.


Don't bother rebooting after tutorial 1 either.
Tutorial 1 - Turn Raspberry Pi into a portable wifi hotspot

See 'CONNECTING' after doing step 2 in the next tutorial to actually connect to the scope as what you have just done changes it a bit.

Tutorial 2 - Make it talk to SkySafari App and the 'Scope

You can now unplug the pi from your router. Plug your USB to serial adapter into the pi, your telescope cable into that and connect it to your scope as you would do with a pc (mine is into the AutoStar hand box) and use it as a stand alone adapter just like the £200 SkyFi adapter!

CONNECTING:
To connect SkySafari to the pi you simply connect your tablet or phone to the pi's network like you would any other wifi network, i called mine Scope, connect using the security key / password you made up in tutorial 1. Open SkySafari and follow step 3 in the second tutorial but with IP address 192.168.0.10 - the port is still 4000 (unless you changed it)

If you are at home and your cable is long enough to reach your router you can plug the pi into that and use your home internet too - which you cant do with the SkyFi adapter!

I am going to shorten my serial cable to make it a neater package, i can always solder new plus to make an extension if i ever need one.


I am also working on finding out how to make it share usb internet so a 4g dongle can be plugged into it when out and about since when you connect to the pi's wifi in the field you will not have internet on the device connected to it.

Also the Pi could possibly be used for imaging or tracking, someone on here will probably know more on this.

Edited by Craig Shaw
Spelling mistake and extra word in tag and title
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Yep, Pi can be used for imaging, guiding, focus control...  pretty much my entire setup is handled by an old RaspberryPi Model B+ (before they changed the board footprint).

See https://www.fastnetserv.com/how-to-make-a-raspberry-pi-3-as-a-3g4g-router/ for configuring as a local router / dhcp server for 3G/4G via USB. Technically you're mostly already there - you just need HostAPD, and depending how you want to do things DNSMasq can help (means no more remembering IP addresses).

 

 

Edited by Marci
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22 minutes ago, Marci said:

Yep, Pi can be used for imaging, guiding, focus control...  pretty much my entire setup is handled by an old RaspberryPi Model B+ (before they changed the board footprint).

See https://www.fastnetserv.com/how-to-make-a-raspberry-pi-3-as-a-3g4g-router/ for configuring as a local router / dhcp server for 3G/4G via USB. Technically you're mostly already there - you just need HostAPD, and depending how you want to do things DNSMasq can help (means no more remembering IP addresses).

 

 

Excellent, i will take a look! The above uses DNSMasq already so i guess it will be the same type of setup.

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