Error Sending: The semaphore timeout period has expired

Support forum for MegunoLink
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Posts: 14
Joined: Sat Dec 31, 2016 4:59 pm

Sat Jan 19, 2019 2:50 pm


My Interface Panel has stopped working and I get the above message when I try to send anything. Any ideas what has gone wrong?
Posts: 401
Joined: Mon May 26, 2014 10:58 am

Sun Jan 20, 2019 8:04 am

Hi Hugh, I'm assuming you're using a bluetooth serial adapter? If so I've seen it before. Its related to issues with the driver. Maybe this page can help. ... connection

Posts: 14
Joined: Sat Dec 31, 2016 4:59 pm

Tue Jan 22, 2019 11:35 am

Thanks Phil.

The error seems to have gone away for now. There is no bluetooth in the system but I do have a very overextended USB chain. Arduino Mega, two Teensys, a USB to serial adaptor and a Vellemann VM110 interface board to a 7-port hub. 7-port hub to a 4-port hub. 4-port hub to a Pegasus Astro Ultimate Power Box - which contains an internal 7-port hub and finally to my computer. One of the devices attached to the Pegasus box is an FTDI usb to serial device. I think the whole thing went into meltdown. I have reconfigured a bit - still have the same chain but have disconnected everything at the far end except the Velleman board and the Arduino Mega and it seems to be working OK with the simplified configuration.

Long term, I am intending to have a radio link between my Computer - which is mounted on my telescope - and the control box with all the other gubbins in it.

Anyway, thanks again for the help.
Posts: 7
Joined: Wed Feb 10, 2021 12:01 pm

Thu Sep 02, 2021 2:56 pm

I have recently been receiving a similar message after moving from an Atmega Arduino to STM32 'Blue Pill'. Might have to start again:-(
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