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INDI Library v2.0.6 is Released (02 Feb 2024)

Bi-monthly release with minor bug fixes and improvements

Programmer Corrosion -- "UDP is killin' me!"

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There was a time I was a reasonable network programmer, but clearly I am overly corroded these days or am missing something. Apparently, I am stuck in the cracks, in that I am not running any Windoze equipment, nor iOS where it appears all the documentation lives for my problem..which is this:

I want to use KStars for my Skywatcher 250P Goto (alt/az) telescope. It works with the indi_synscan_telescope driver, but requires SynScanApp running on a Tablet as an intermediary. I have tried moving the scope via a USB->TTY device, without success and would be fine with writing something to do at least that simple task if I could see how the SynScanApp is communicating. For some reason, I cannot.

The SynScanApp works with tne built-in WiFi (no dongle) of my scope. I can see (using WireShark) UDP packets being sent via multicast outbound from the tablet on discovery by the SynScanApp. There is apparently SOME kind of communication, as the scope can then be controlled by the tablet, but I am not seeing any traffic (TCP or UDP) from the scope to the tablet or tablet to scope. I have tried many moving and other type operations and monitored WiFi traffic without finding a single byte of traffic after the initial discovery query from the tablet. I have written a UDP script that duplicates the SynScanApp UDP packet send for the original discovery and receive no reply. Due to some Internet suggestions that contradict the SynScan documentation, I have tried a variety of ports for the UDP discovery query including 11880 as witnessed being used by the SynScanApp and 11881, 11882 and 11883 with no reply.

SkyWatcher support has not answered my email. I don't know if they are closed for CV19 or the question doesn't have an easy answer.

I have wondered if this newer scope might be using bluetooth, but I rather doubt that, though it is something I may check next.

None of the Alt/Az mount indi drivers will connect to my scope via ethernet or USB->tty cable. It will connect using the indi_synscan_telescope driver, if I use a USB->serial cable to the handset, but once again requires an intermediary device (the handset), which introduces other obstructions.

Any assistance in figuring out how the SynScanApp (android) communicates with the built-in WiFi (or alien psychic mind meld) and how to monitor the process would be GREATLY appreciated.
Last edit: 3 years 9 months ago by Jon Carleton.
3 years 9 months ago #55266

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I don't know anything about these devices to offer help. On the surface it kind of sounds like you are just not seeing the WiFi communication that is taking place. While not seeing anything specific, here is what I encountered doing a quick search for a mount that seemed similar, in case the trigger something.

www.networkworld.com/article/2231903/wir...romiscuous-mode.html

AZGTi Mount:

Power LED: The power LED serves as a power-on indicator and provides
other statuses.
1. Steady on: Internal Wi-Fi is off.
2. Intermittent one flash: Internal Wi-Fi is on.
3. Intermittent two flashes: App has connected to internal Wi-Fi.
4. Intermittent three flashes: Internal control board has entered
firmware update mode.

Wi-Fi Access Point SSIDSynScan_xxxx
Access Point IP Address192.168.4.1
Network ProtocolUDP, Port 11880

User must connect to the mount’s Wi-Fi within 15 minutes after turning on power.

The Wi-Fi will be turned off automatically if no connection is estabilished within
15 minutes,

By default, the SSID of the built-in Wi-Fi is “SynScan_xxxx” and there is no password.

User can download Skywatcher’s “SynScan” app from App Store or Google Play to configure
the mount’s built-in Wi-Fi.

Reset Wi-Fi configuration to factory default by turning on the power without the SynScan
hand control connected and no App operations via the Wi-Fi connection for 4 hours.
3 years 9 months ago #55282

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