Carbon monoxide sensor in Home Assistant - everyone does it wrong!
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- เผยแพร่เมื่อ 20 พ.ค. 2024
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In this video, I'm making a carbon monoxide monitor for my home using an MQ7 carbon monoxide sensor, a DHT11 temperature and humidity sensor, and a NodeMCU microcontroller board.
This sensor is beneficial for places where there is a fire source such as a stove or boiler, to monitor carbon monoxide build-up and adjust ventilation accordingly.
There are plenty of tutorials on using the MQ7 sensor, but none are actually measuring as per what the datasheet requires. It states that the sensor should be heating up and cooled off in cycles, and only measured at the end of each cycle. To achieve that, the MQ7 module needs to be modified so instead of having a digital output pin, we can use that pin to control the applied voltage on the heater inside the sensor.
This is not a simple modification so only attempt it if you are comfortable working with SMD components. In the end, one of my sensors failed for unknown reasons so approach this project at your own risk.
If you like what I do, feel free to support the channel!
www.tastethecode.com/support
Tools and materials used in the video:
MQ7 Carbon Monoxide Sensor Module - s.click.aliexpress.com/e/_Dmq...
DHT11 Temperature/Humidity Sensor - s.click.aliexpress.com/e/_DEv...
NodeMCU Development Board - s.click.aliexpress.com/e/_mOv...
ESP32 board - s.click.aliexpress.com/e/_oCw...
Soldering Rework Station - s.click.aliexpress.com/e/_onZ...
Desoldering wire - s.click.aliexpress.com/e/_EQ7...
Wire snippers - s.click.aliexpress.com/e/_Dd9...
Wire strippers - s.click.aliexpress.com/e/_DmQ...
Tweezers - s.click.aliexpress.com/e/_Ddk...
Project box - s.click.aliexpress.com/e/_Dkw...
RD6012 Bench power supply - s.click.aliexpress.com/e/_DBQ...
The ESPHome Devices guide on the modification can be found below:
devices.esphome.io/devices/MQ-7
My recording gear:
Canon M50 Mark ii - s.click.aliexpress.com/e/_ALp9Sp
Dragon Touch 4K Action Camera - s.click.aliexpress.com/e/_mrc...
USB Condenser Microphone - s.click.aliexpress.com/e/_DF5...
Tripod - s.click.aliexpress.com/e/_Del...
Phone tripod mount - s.click.aliexpress.com/e/_s9WaiJ
The MQ7 sensor datasheet can be found below:
www.sparkfun.com/datasheets/S...
Carbon monoxide sensor in Home Assistant - everyone does it wrong!
#carbonmonoxide #sensor #homeassistant #CO #tastethecode
00:00 - Introduction to MQ7 sensor
01:05 - Overview of the final CO monitor device
01:27 - How to properly use the MQ7 sensor
02:08 - Overview of available modules for the MQ7 sensor
02:40 - ESPHome recommended modification
03:44 - Sponsor info
04:24 - How I modified my MQ7 module
05:05 - Sensor calibration
05:35 - Creating an enclosure
06:19 - Code for the MQ7 sensor in Home Assistant
07:08 - Testing the sensor readings
08:02 - Challenges and issues with the modification
09:50 - Summary and next steps
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This video is a part of a 26 video series on Home Automation DIY Devices as part of the Alphabet Superset challenge! www.alphabetsuperset.com/
Thanks @struthless for organizing this! #alphabetsuperset - วิทยาศาสตร์และเทคโนโลยี
Nice job
Thanks!
I've bought one a few months ago.
I find the sensor to be very flaky.
I did a similar test with some scented sticks in a glass jar and it took quite long for the sensor to spike. It was more of a gradual increase and same for the decrease when I took the sensor out of the glass.
Not a nice spike as in your video.
I've read somewhere that the ZE07-CO does a better yob, but I couldn't get any data out of it so far.
This inspires me to try both sensors again tomorrow 🙂.
I'm not familiar with the ZE07 sensor but I might order one to give it a go. There is also another one that I want to try, the MICS-5524. In my case the readings are taken once every 2,5 min, because of the heating/cooling cycles so maybe that is why you see a spike. Also, I guess that the scent sticks would produce a lot more airborne particles like PM2.5 and PM10 instead of CO gas as they are not burning that much.
@@TasteTheCodemics-5524 seems to be general voc sensor so it has low selection to CO while ze07 looks like to be more specialised on CO only.
Also you should know that the whole MQ series (includes about 10 different sensors) is actually all the same sensor with only difference is they have different resistors. I mean MQ series just reacts to any gas with carbon, therefore your sensor will also react to any such gas and its readings would not be selective to solely CO. And of course you can not measure CO with it with any degree of precision. It can just tell whether there is more carbon in the air or less.
MQ sensors also have about 1 year (do not remember exact number) of lifetime while on the fresh air due to carbonisation of sensor material, and it does not matter whether it worked for that time or just layed down powered off.
As for ZE07 they claim this sensor to have good selectivity but do not provide any additional data on selectivity in datasheet
There is also CO sensor from Gravity but it's quite expensive. They claim this sensor to have good selectivity and even provide selectivity table in datasheet (thought there is still influence of other gases remain)
@@binariti Hey, thanks for the great info. I still haven't looked into other sensors but I will definitely do. I'm aware of the different MQ series sensors but I was unaware of their shelf life so I'll research this a bit more. Thanks again!
How has the sensor been working for you so far? Have you done any testing against other sensors to confirm the accuracy of yours? Also are the values from your sensor logged in HA for any period of time? I'm hoping to find some way to view trends based on different activates in my home over longer periods of time i.e. weeks or months
Honestly, not great... The values seem tp be all over the place but yes, HA logs them for long periods. There were some other ones recommended to try out like the MICS-6814 but I haven't had the time to do so.
nice job, Dude
Thanks!
Could you use the camera with this NCO board as well?
I haven't used a camera so far but as I know they are interfaced through SPI so I do not see why the two can't work together.
Could you please tell me which transistor you used?
I used a 2m2222 because that is what I had on hand. The original article asks for a SL2310 mosfet.
@TasteTheCode Oh thank you. Do you think changing the transistor causes a significant change in the circuit? I'm planning to use a BSN254 transistor. Will that work?
Hmmm I can't say for sure but I think it will not, as long as the transistor can handle it. Yours seems beefy enough.
please write what mosfet you used
I used a 2n2222 transistor as I did not had mosfet on hand but the original article calls in for a SL2310
code please
The code is available in the link from ESPDevices.