S8

Gases - CO2 Senseair NORMAL

../_images/P052_S8_1.jpg

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

../_images/P052_Setup_S8_1.png

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).

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.

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

../_images/P052_S8_2.jpg ../_images/P052_S8_3.jpg