I believe that “Low” and “High” are measurements of the pulse widths of the signal, or similar.
I did some testing with some other 433MHz door/window sensors from Banggood to see what codes they transmitted. I don’t know if these would be applicable to others… These are “GS-WDS07” sensors from here: https://www.banggood.com/GS-WDS07-Wireless-Door-Magnetic-Strip-433MHz-for-Security-Alarm-Home-System-p-1174915.html at about $5.15 each. The sensors that I have are powered by a single AAA battery.
On the PCB, there’s provision for a “tamper” switch, but nothing is populated. If you short the pins, you can activate the “tamper” function and get a code transmitted.
Interesting that these things seem to have a programmer header, perhaps with pins labeled
I wonder what to make of that
So, for one of my sensors, I get these codes:
12F70A - open
12F70E - closed
12F707 - tamper
12F706 - low battery
The low battery code is emitted when the battery voltage is below a volt. I removed the battery, and connected my variable bench power supply, and slowly reduced the voltage. Going by the display on my power supply, I think about 0.8 V, but I’m not sure how accurate it is, and I didn’t bother to measure the actual voltage that it tripped at, mostly just looking to see if it did anything with a low power supply voltage.
Also of interest, this particular sensor seemed to have about a 28 microamp standby current. This I measured with 4.5 digit Fluke 8050A bench multimeter and should be pretty close. Of course, the current spikes up quite a bit when it decides to transmit… I didn’t bother to try to measure that.
I only got around to doing the low battery test on one of the sensors. The other 3 had these codes:
13D20A - open
13D20E - closed
13D20F - tamper (no switch actually installed) (the tamper code on this is different from the rest - maybe have to re-test?)
13DA0A - open
13DA0E - closed
13DA07 - tamper (no switch actually installed)
13FD0A - open
13FD0E - closed
13FD07 - tamper (no switch actually installed)
Sorry that I didn’t have an answer to your specific question. Maybe this could be helpful if these devices share some common transmitter chip?