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Lenovo Rechargable PIR Motion Sensor
Model reference: ZG38C02927
Lenovo Rechargable PIR Motion

Available from:
Aliexpress.com
Jbhifi.com.au





Flashed with:
Serial port

GPIO #Component
GPIO00 User
GPIO01 Tuya Tx
GPIO02 User
GPIO03 Tuya Rx
GPIO04 User
GPIO05 User
GPIO09 None
GPIO10 None
GPIO12 User
GPIO13 User
GPIO14 User
GPIO15 User
GPIO16 User
FLAG None

Template

{"NAME":"Lenovo PIR","GPIO":[255,107,255,108,255,255,0,0,255,255,255,255,255],"FLAG":0,"BASE":54}

I bought this sensor off AliExpress, it came with a sticker hiding the Lenovo branding.

Warning: Wi-Fi sensors still have a slow response time compared to always on wired or zigbee ones. This will not work in critical locations where a fast response is needed. This sensor has the benefit of being rechargeable.

Identified with MCU Product ID: {"p":"105awlczxldrrpfc","v":"1.0.0"}

Flashing

To have best results with this type of device I strongly recommend compiling a stripped down binary. There’s an unofficial binary, compiled from current development release. Flash at your own risk. Tuya-Convert was not possible due to new PSK used.

Flash using the TYWE3S pins but make sure the battery is disconnected and the power button is in the off position. After flashing you need to disconnect power from the serial-to-USB adapter and reconnect the battery and power the sensor with it.

Configuration

Change device to a TuyaMCU module (or apply the provided template, result is the same)

Module 54

Disable multipress button options to prevent a device reset or Wi-Fi AP config mode, disable Power Cycle recovery, turn off bootloop protection, turn off sending superfluous MQTT

Backlog SetOption1 1; SetOption65 1; SetOption36 0; SetOption90 1

Switch the device to battery powered sensor mode (fnId 51):

TuyaMCU 51,51

Check with TuyaMCU for the following configuration:

 {"TuyaMCU":[{"fnId":11,"dpId":1},{"fnId":51,"dpId":21}]}

Functions

When it detects motion it boots up Tasmota then puts the PIR sensor in non-detect mode for around 30 seconds which means there will be no motion triggers during that time.

With a static IP set it takes under 4 seconds to send first MQTT message (00:00:03 MQT: tele/motion/LWT = Online (retained)). It is recommended to set PIR in your home automation solution as activated on LWT online message and deactivated on LWT offline message or after some time. Do not enable SetOption66 to make boot time as fast as possible.

It sends motion detected status on {"TuyaReceived":{"Data":"55AA0005000501040001000F","Cmnd":5,"CmndData":"0104000100"}} but not reliably. Waiting for that message to be transmitted takes a second or two longer and sometimes never happens.

Sensor never sends the battery status message while in regular working mode. It is not transmitted when in detection mode so there is no realistic way to read battery data.

{"TuyaReceived":{"Data":"55AA00050005030400010213","Cmnd":5,"CmndData":"0304000102"}}

Device can get stuck in start-up mode, usually happens after powering on with power button or messing with reset button too much. The red LED will be on constantly and the battery status message from dpId 3 will appear in console in short intervals. To exit that mode and enter detection mode send SerialSend5 55AA000200010002.

You can try using a rule that will send the command whenever the battery message is sent:

Rule1 on TuyaReceived#CmndData=0304000102 do serialsend5 55AA000200010002 endon on TuyaReceived#CmndData=0304000101 do serialsend5 55AA000200010002 endon

The rule will not trigger when battery status is low (00) so you will know to change batteries if it gets struck in that mode.