Flashing Beca BAC-002 Thermostat with OpenBK and Adding Sensor
Hi all, i would like to flash my thermostat with openbk.
There are several version of this thermostat.
The oldest has a WB3S chipset inside.
The newest has a CB3S chipset.
I would also like to add a temperature/humidity sensor to the wifi chip soldering it directly on the board and i'd like to know the state of the relay (on or off) with this little mod (Link)
I've already the thermostat working with local-tuya, an integration for home assistant that doesn't rely on tuya cloud but thermostats aren't disconnected from the cloud.
So these are dpID the thermostat is using.
There are several version of this thermostat.
The oldest has a WB3S chipset inside.
The newest has a CB3S chipset.
I would also like to add a temperature/humidity sensor to the wifi chip soldering it directly on the board and i'd like to know the state of the relay (on or off) with this little mod (Link)








I've already the thermostat working with local-tuya, an integration for home assistant that doesn't rely on tuya cloud but thermostats aren't disconnected from the cloud.
So these are dpID the thermostat is using.
Spoiler:
name: BAC-002 Thermostat (C) - WB3S chip
primary_entity:
entity: climate
dps:
- id: 1
type: boolean
name: power
mapping:
- dps_val: false
value: "off"
hidden: true
- id: 2
type: integer
name: temperature
unit: C
range:
min: 10
max: 70
mapping:
- scale: 2
- id: 3
type: integer
name: current_temperature
unit: C
mapping:
- scale: 2
- id: 4
type: string
name: operation_mode
mapping:
- dps_val: "0"
value: program
icon: mdi:calendar
- dps_val: "1"
value: manual
icon: mdi:hand-pointing-up
hidden: true
- id: 5
type: boolean
name: preset_mode
mapping:
- dps_val: true
value: eco
- dps_val: false
value: comfort
- id: 102
type: string
name: hvac_mode
mapping:
- dps_val: "0"
value: cool
icon: mdi:snowflake
- dps_val: "1"
value: heat
icon: mdi:wheather-sunny
- dps_val: "2"
value: fan_only
icon: mdi:fan
- id: 103
type: string
name: fan_mode
mapping:
- dps_val: "0"
value: auto
icon: mdi:fan-auto
- dps_val: "1"
value: high
icon: mdi:fan-speed-3
- dps_val: "2"
value: medium
icon: mdi:fan-speed-2
- dps_val: "3"
value: low
icon: mdi:fan-speed-1
secondary_entities:
- entity: light
name: Display
category: config
deprecated: climate hvac_mode
dps:
- id: 1
type: boolean
name: switch
mapping:
- dps_val: true
icon: "mdi:led-on"
- dps_val: false
icon: "mdi:led-off"
- entity: lock
name: Child Lock
category: config
dps:
- id: 6
type: boolean
name: lock
mapping:
- dps_val: true
icon: "mdi:hand-back-right-off"
- dps_val: false
icon: "mdi:hand-back-right"
- entity: select
name: Operation Mode
dps:
- id: 4
type: string
name: option
mapping:
- dps_val: "0"
value: Program
- dps_val: "1"
value: Manual
primary_entity:
entity: climate
dps:
- id: 1
type: boolean
name: power
mapping:
- dps_val: false
value: "off"
hidden: true
- id: 2
type: integer
name: temperature
unit: C
range:
min: 10
max: 70
mapping:
- scale: 2
- id: 3
type: integer
name: current_temperature
unit: C
mapping:
- scale: 2
- id: 4
type: string
name: operation_mode
mapping:
- dps_val: "0"
value: program
icon: mdi:calendar
- dps_val: "1"
value: manual
icon: mdi:hand-pointing-up
hidden: true
- id: 5
type: boolean
name: preset_mode
mapping:
- dps_val: true
value: eco
- dps_val: false
value: comfort
- id: 102
type: string
name: hvac_mode
mapping:
- dps_val: "0"
value: cool
icon: mdi:snowflake
- dps_val: "1"
value: heat
icon: mdi:wheather-sunny
- dps_val: "2"
value: fan_only
icon: mdi:fan
- id: 103
type: string
name: fan_mode
mapping:
- dps_val: "0"
value: auto
icon: mdi:fan-auto
- dps_val: "1"
value: high
icon: mdi:fan-speed-3
- dps_val: "2"
value: medium
icon: mdi:fan-speed-2
- dps_val: "3"
value: low
icon: mdi:fan-speed-1
secondary_entities:
- entity: light
name: Display
category: config
deprecated: climate hvac_mode
dps:
- id: 1
type: boolean
name: switch
mapping:
- dps_val: true
icon: "mdi:led-on"
- dps_val: false
icon: "mdi:led-off"
- entity: lock
name: Child Lock
category: config
dps:
- id: 6
type: boolean
name: lock
mapping:
- dps_val: true
icon: "mdi:hand-back-right-off"
- dps_val: false
icon: "mdi:hand-back-right"
- entity: select
name: Operation Mode
dps:
- id: 4
type: string
name: option
mapping:
- dps_val: "0"
value: Program
- dps_val: "1"
value: Manual
Comments
Hello, this should be easily doable, we actually already had a similiar topic here: https://www.elektroda.com/rtvforum/topic4003974.html Have you seen that? The topic above even includes the relay... [Read more]
First of all, thank you for all your effort on this project and thank you for your reply. I'm aware of the other thread, I've already studied it. I will try to backup the device and to flash the new firmware.... [Read more]
Let's start with flashing and configuring one device, we need to test the whole setup first. I am not sure if just having pogo pins solves all problems, because you still may need to cut the connection... [Read more]
Sorry for late reply, very busy week. Yesterday i had some spare time. I've desoldered two resistor which communicate with MCU. No luck with pogo pins, so i've soldered four wires to wifi chip. At... [Read more]
OBK config will not help for TuyaMCU device. What does the TX2 log output say? [Read more]
Well, i don't see any output connecting on tx2. I'm using putty in serial mode to see if there is an output, am i doing wrong? i'm using this as usb-uart adapter. Hope it is good. p.s. sorry for... [Read more]
how do you power your device, can you make a photo of connections?" [Read more]
https://obrazki.elektroda.pl/2431763200_1705246683_thumb.jpg This is how i am powering the device. Now i'm trying to use a usb-esp01 adapter, to see if it helps. Now the led screen of the thermostat... [Read more]
You are using your USB to UART converter incorrectly. You should use jumper to connect 3.3V to VCC on USB to UART converter to select 3.3V voltage levels and power the device externally from a reliable... [Read more]
Hi, sorry for late reply. I haven't been able to flash new firmware. i will try to do it in a few days. During the first attempt, I have been able to backup the original flash. if you want it i can... [Read more]
Hi all, i want to "hi-jack" this post to post my first response on the forum. I just finished flashing 11 of these units with a simple pogo-pin set-up so if anyone needs some easy solution to flash these... [Read more]
Some Tuya thermostats support connecting external sensor out of the box, is it the case here? Do you have a manual? If not, then we will have to try more DIY approach, but there is one problem - sensor... [Read more]
yeah this one does not support an external sensor out of the box so i'll probably have to go for the DIY approach. Please see the manual attached. I'm also posting the firmware backup for the other user... [Read more]
Do you have it still paired with App? Does it have a calibration option there? Added after 43 : EDIT: There is calibration mentioned in manual. [Read more]
No i never paired it with the app to begin with unfortuantely, but there is a menu setting. It's also visible in the manual [Read more]
Hm ok, we have a backup so we also can do dpID extraction, maybe @divadiow can also help. There are also some dpIDs in the first post. [Read more]
柏益加温控器(空调) { "gw_bi": { "uuid": "7066c8c661a88a2e", "psk_key": "cw1ygXBCnRDriFY12daQJPgnSBiuBfu6sincM", "auth_key": "c2kQykz6kTORTKuRSh6rgeHLpZcycGY2", "ap_ssid":... [Read more]
No calibration? [Read more]
So what are you saying is to try to use the temperature compensation dpID to "mimic" an external sensor by modifying what the internal sensor read? I've not seen this value being exposed by the tuya mcu. See... [Read more]