Unable to download dataflash logs through 8266's WiFi

In some of my projects I use PixRacer R15, which comes with a pluggable ESP 8266 WiFi module.

I have recently found with two such boards that they generally work (e.g. they show pitch/roll/yaw, and they allow modifying configuration), but whenever I try to download the dataflash logs, the WiFi suddenly stops, comes back in few seconds, and keeps dying this way until I stop attempts to download logs.

At first I thought this is an issue with the memory, as one of my boards has only something like 20 kilobytes of free RAM. However, this also happens with another board with some 90+ free kilobytes.

What shall I do? The main boards run ArduCopter 4.1.0-beta{5,6}. The 8266 boards were used out-of-box - which might be an issue, however, I assume the differences between firmware versions on 8266 are related to Mavlink2 and main board’s firmware updates, and not to the core functionality.

I have those radios on most craft including 3 PixRacers. I don’t use them for log download because it’s slow but I just tried it on one and it times out at various % each time before completing as you found. If you monitor the Link Quality while doing so you may see it start to drop and then Nan and that’s the end.

I have some rover with Matek H743 and ESP8266 Modules connected.
For all rovers I had to reduce the SERIAL baud rate from 921 kBit to 230 kBit. Otherwise, the ESP8266 WLAN was constantly disconnecting and reconnecting. But 230kBit is a bit slow for log download.


Good info. 921 kbit is slow for log download :slight_smile: But I used to use BT radios and those are terrible. For several reasons…

That helped very much, thanks!

For such a novice as I am, the following hints might be helpful:

  • You have to change baud rates both in Ardupilot’s config and in 8266 through its web interface (somewhere at in my case). Otherwise they will not understand each other. A board reboot is required.
  • You have to find which UART/USART is responsible for your 8266 connection, and which SERIAL corresponds to it. For a Pixracer R15, it is SERIAL5.

The log download rate indeed feels slow, but that is partially because APM Planner tends to corrupt some of the downloaded chunks and keeps requesting them few times per second, which slows everything down even more. (This happens even with USB actually). Maybe when someone finds and fixes that buffer overflow, even 230 will feel much better.