S8¶

Gases - CO2 Senseair NORMAL

Introduction¶

This is a CO2 sensor from Swedish company Senseair.

Specifications:

400 to 2000 ppm
5V (4.5-5.25VDC)
Peak 300mA, avarage 30mA
8.5 x 33.5 x 20 mm
UART communication
15 years life span
No burn-in needed, will stabilize after 8 days at worst depending on placement environment

Wiring¶

Circuit wiring (S8 seen from PCB side, with the 5 vias down and the 4 vias up):

ESP               S8
GPIO (7)   <-->   TX (3rd via [middle] of the 5 vias)
GPIO (8)   <-->   RX (4th via [right of TX])

Power
5.0V       <-->   VCC (4th via of the 4 vias, 300 mA peak/30 mA average)
GND        <-->   GND (3rd via [left of VCC])

Set up the S8 according to this simple schematics. If you want to take extra precautions you should add 47R resistor or similar to the TX and RX signals (this is not used in the pictures below). In this example we use the Wemos D1 mini as the host of the 5V input to the S8 and connect the Wemos to USB for power.

Danger

Power needed: 4.5-5.25V. PLEASE OBSERVE THAT FEEDING THE S8 WITH 5.2+V WILL DAMAGE THE INTERNAL LAMP AND BREAK THE UNIT - GIVING FALSE VALUES!

Setup¶

Task settings¶

Device: Name of plugin
Name: Name of the task (example name CO2)
Enable: Should the task be enabled or not

Sensor¶

GPIO <– TX: TX is generally set to GPIO 13 (D7).
GPIO –> RX: RX is generally set to GPIO 15 (D8).
Sensor: Only Carbon Dioxide is supported by the S8.

Note

TX GPIO 1 (D10) and RX GPIO 3 (D9) is hardware serial and have been reported to work better for some users over time compared to the bit-banging (soft) serial used over GPIO 13 and 15.

Data acquisition¶

Send to controller 1..3: Check which controller (if any) you want to publish to. All or no controller can be used.
Interval: How often should the task publish its value (5..15 seconds is normal).

Indicators (recommended settings)¶

Indicator	Value Name	Interval	Decimals	Extra information
Error status	N/A			Used for tSense (K70), K30, K33
Carbon dioxide	ppm	15	0
Temperature	N/A			Used for tSense (K70), K30, K33
Humidity	N/A			Used for tSense (K70), K30, K33
Relay status	N/A			Used for tSense (K70), K30, K33
Temperature adjustment	N/A			Used for tSense (K70), K30, K33
ABC period	N/A			Used for tSense (K70), K30, K33

Note

If you want to use the relative carbon dioxide percentage (2000ppm = 100% and 350ppm = 0%) you should use this 100-(2000-%value%)/(2000-350)*100 as a formula. And instead of ppm as value name you should use RCO2 (relative CO2) and 1 decimal.

Rules examples¶

on CO2#Level do
 if [CO2#Level]>2000
   Publish,%sysname%/Alarm,CO2 level is too high!
 endif
endon

Commands available¶

Command (GPIO/Value)	Extra information
`senseair_setrelay,<value>` Value: `1` will set the relay to ON. `0` will set the relay to OFF. `-1` will remove control over relay.	Used in tSense (K70) to set the relay to either `1` or `0`. Observe that using this command will take over the control of the relay from the tSense. If you want to give the control back you use the `-1` value.

Command (GPIO/Value)

Extra information

senseair_setrelay,<value>

Value:

1 will set the relay to ON.

0 will set the relay to OFF.

-1 will remove control over relay.

Used in tSense (K70) to set the relay to either 1 or 0. Observe that using this command will take over the control of the relay from the tSense. If you want to give the control back you use the -1 value.

Where to buy¶

Store	Link
AliExpress	Link 1 ($)
Ebay	Link 2 ($)
First Byte	Link 3 ($)

$ = affiliate links which will give us some money to keep this project running, thank you for using those.

More pictures¶