[heebyjeeby]

Hi,

I have built my Air Quality Monitor and am testing it  sitting it outside on a bucket. There is no enclosure for it yet.

CO2 reading seems a little high at about 600 -700 ppm, think it should be about 400. Is this a reasonable measurement?
Is the sensor reading ok? At first boot, it reads about 1200 - 1300, and then drops to 600 - 700.

The plantower pms7003 is working, PM readings are very low on this with AQI of about 2 or 3 max. Either the sensor is not working well or I have very clean air! I live in rural Ireland, about 1km to nearest road, and we had a lot of wind and rain yesterday, so I think I would expect them to be low at the moment.

My thinkgspeak channel is here: https://thingspeak.com/channels/563450

Any comments are welcome, not sure what my ballpark readings should be.

Thanks,
Heeby

[hornychz]

Hello

And congratulations to complete the construction.   

But the values PM2.5 (they respond AQI) and PM10 seem really strangely small.
And CO2, on the contrary, looks like measured inside the building ... 
Maybe it would be good to turn on the debug mode and publish here the output of the serial monitor ...

Good luck!

[heebyjeeby]

Thanks for replying hornychz.

Here is the results from the debug.

CO2 seems very high, maybe it is me breathing near the CO2 sensor as it is connected to laptop for debugging.
You can see that the CO2 sensor does a few readings of 431, and then a high reading. I think the readings of 431 are just the sensor starting up.

I am not sure if the PM sensors are working correctly, or if I have very clean air.

Code:

    WeatherDuino 4Pro
Air Quality Monitor v8.0 b001

Please wait 30s
Configuring CO2 Sensor
Setting measurement range to: 5000
FF,99,1,0,0,0,0,0,66,
66,66
Measurement range changed!
Disabling ABC Funtion
Reseting Sensor
21,D,AC,FC,0,1,35,70,0,
Calculated crc: A5
Wrong reply from CO2 sensor!
FF,86,1,9A,38,0,0,0,A7,
Calculated crc: A7
CO2 read: 431 - Temp: 16

FF,86,1,9A,38,0,0,0,A7,
Calculated crc: A7
CO2 read: 431 - Temp: 16

FF,86,1,9A,38,0,0,0,A7,
Calculated crc: A7
CO2 read: 431 - Temp: 16

FF,86,1,9A,38,0,0,0,A7,
Calculated crc: A7
CO2 read: 431 - Temp: 16

FF,86,1,9A,38,0,0,0,A7,
Calculated crc: A7
CO2 read: 431 - Temp: 16

FF,86,1,9A,39,0,0,0,A6,
Calculated crc: A6
CO2 read: 431 - Temp: 17

FF,86,1,9A,39,0,0,0,A6,
Calculated crc: A6
CO2 read: 431 - Temp: 17

FF,86,4,6C,39,0,0,0,D1,
Calculated crc: D1
CO2 read: 1190 - Temp: 17

FF,86,4,70,39,0,0,0,CD,
Calculated crc: CD
CO2 read: 1194 - Temp: 17

Init MH-Z19 Ended


Waking up the dust sensor...
Reading will be done 40s later.

Reading the dust sensor...

PMS7003 readings:
PM2.5: 1.41 ug/m3
PM10 : 2.12 ug/m3
PM2.5_1H_Avg : 1.41
PM2.5_NowCast: 1.41

FF,86,4,76,39,0,0,0,C7,
Calculated crc: C7
CO2 read: 1160 - Temp: 17


Waking up the dust sensor...
Reading will be done 40s later.

Reading the dust sensor...

PMS7003 readings:
PM2.5: 0.00 ug/m3
PM10 : 0.72 ug/m3
PM2.5_1H_Avg : 0.71
PM2.5_NowCast: 0.71

FF,86,4,7C,3A,0,0,0,C0,
Calculated crc: C0
CO2 read: 1167 - Temp: 18

Heeby

[werk_ag]

CO2 seems very high, maybe it is me breathing near the CO2 sensor as it is connected to laptop for debugging.

Yes, breading near the sensor is enough to raise the readings.
You can test the PM sensor, by using any kind of smoke, incense is the better. PM readings will rise quite quickly.

[heebyjeeby]

So I just did a quick smoke test on the PM sensor, and managed to get PM2.5 reading of 127.1 ̣µg/m³ and a PM10 reading of           152.36 µg/m³. The AQI was an unhealthy 187. The sensor appears to be working ok. On the next read 10 minutes later, the values had more or less halved.

I managed to get the CO2 meter reading to about 3000 ppm by breathing heavily on it, but it is very slow to drop down under 1000.
Perhaps it needs a good airflow around it. If tomorrow is dry I will run a mains  extension lead out in to the middle of my garden and test the monitor readings there all day - I don't have an enclosure yet. Waiting for a lcd display to arrive which will make testing much easier as I wont need to be in range of the Pro2 plus receiver.

Thanks,
Heeby

[werk_ag]

Bear in mind that the results of the sensor readings are averaged over a period of time, and not instant values.
PM2.5 its an average of the last 12 hours, which follow the recomended "nowCast" technique (last hours have a higher ponderation in the average calculation).

C02 is a simple 1 hour arithmetic average.

[heebyjeeby]

Air quality monitor seems to be working well now. PM readings are generally quite low, as expected, but rises quickly if someone is smoking. In my kitchen the co2 rises quite high at night, around 1500 ppm, and drops down to about 430 with ventilation in the morning. My 3 dogs sleep in the kitchen.

I should probably put this in a new thread but I am calibrating my solar and UV sensors at the moment. Solar readings are quite accurate without any adjustments, maybe a little levelling needed, but UV readings are nearly double what is expected. Do I just adjust the multiplier in the calculation code or spend more time levelling everything?  It's a uvm-30a sensor.

The soil/leaf interface is working great with 4 DS18B20 temp probes.

Thanks,
Heeby

[werk_ag]

... but UV readings are nearly double what is expected. Do I just adjust the multiplier in the calculation code or spend more time levelling everything?  It's a uvm-30a sensor.

The Solar Radiation kit with our solar cell, is sent pre-calibrated, so any adjustment should be minimal, regarding the UV sensor, depending of the UV transparency of the material used to cover the UV sensor, on Config_Options adjust here:

Code:

const byte UV_Transmission = 65;    // UV Transmission percentage of UV sensor cover material.

Don't use the multipliers for UV or Solar readings.

[heebyjeeby]

I have been testing the uv sensor and solar cell without any protective cover, with the UV transmission percentage set to 100. If rain is forecast, I put them in a plastic ziplock freezer bag. I will try lowering the percentage to get a more realistic uv setting. The solar cell is very well calibrated, very similar readings to a couple of nearby Davis stations.

Perhaps of interest, I have found that covering the sensors with freezer bag doesn't change UV or solar readings - same readings if sensors are behind the plastic or not. They are Ikea freezer bags.

Heeby

[hornychz]

Hi,

This material is good for attempts, but I am afraid that it will not survive long-term operation.
On the one hand, it will definitely be a lot of dirty, and it will probably be totally degraded in time thanks to UV radiation.
I highly recommend using a good quality cover glass with high UV transmittance, as described eg. in the WiKi.

Good luck in construction.