Weller WX serial protocol

[owiecc]

Anyone got a clue what the serial protocol is for the WX stations? I only found this post at dangerous prototypes, but in true internet fashion they say they have the protocol but do not post it . I cannot find anything useful on Weller's website.

My WX2 died. The display backlight turns on and that is it. I want to connect it to a computer and see if it is still alive and only the display died. I emailed Weller about service - no answer.

[phil from seattle]

from the DP thread, it looks like it's a serial protocol.  That should be pretty easy to sniff out if you can't find the actual protocol definition. I'd check it first with an Oscope to see if it's really RS232 or just async (logic level). I'd bet the latter.

[ehagerty]

Hi, first post so forgive me if I lack correct etiquette.  I don't think I can legally give you their document, but if you google "weller Application Note: WAN12-0006" that's what you are after.  I spoke with their AMAZING tech support and they sent it right over - such awesome people at that company IMO.

What I don't yet know, but have asked, is if you can interface via the USB bus or have to use the RJ11 on the back of most units - which is what the serial chip is attached to.  IIRC it is an analog devices ADM3251E or similar.

If you do anything interesting with the comms do post it as I'd love to know what you learn.

[ehagerty]

Just a follow up - you must use the RJ11 port on the rear - although they are working on a USB interface it isn't part of the current product line.

[kubark42]

Found easily thanks to @ehagerty!

[0xEBD]

Late follow-up, as @ehagerty asked for anything interesting done with the comms:

I started a side project “fumeXsense WX2” to automate my fume extractor based on the WX2 state, using the protocol from WAN12-0006. Channel ON switches the extractor on via a Shelly smart plug; standby/off switches it off after a configurable run-on delay. The target is an ESP32-C3.

Note: I also use this project to fine-tune some AI-assisted SW engineering workflow ideas. What's published so far is a PC-based PoC with a fully working Python tool, entirely AI-coded. A reviewed reference implementation for the ESP32-C3 comes later.

Two findings that answer questions from this thread:
- It is real RS-232 levels, not logic level. A MAX232/MAX3232 level shifter between the WX2 and the UART works fine (1200 baud, 8N1).
- The rear port is a 6P6C jack ("RJ12"). A 6P4C "RJ11" cable also fits and contacts the middle pins, which carry GND, RX and TX.

Hardware, pinouts, protocol notes and lessons learned:
github.com/0xEBD/fumeXsense