@skywatch said in RF Nano = Nano + NRF24, for just $3,50 on Aliexpress:

Of course there is also the question as to if these are genuine Nordic NRF24L01+ chips or fake Chinese clones again......

I don't think there is any question on that

@alowhum said in RF Nano = Nano + NRF24, for just $3,50 on Aliexpress:

The RF-Nano has this as a comment:

Good to know but really easy to do even for newbies.
There's also this comment:
Works good, I'm using with mysensors library #define MY_RF24_CE_PIN 10 #define MY_RF24_CS_PIN 9

@alowhum said in Particle Powered Air Quality Sensor Logging to Google Docs:

Nice work.

Does it use the temperature and humidity values to optimise the fine dust calculation?

No it doesn't.
And by the way PM10 values are worthless, they are evaluated based on PM2.5 values. Meaning if you put the sensor in an environment with only 2.5-10 µm sized particles, it will say 0ug/m3.
Not saying the sensor is bad, it's good but only for pm2.5. I suspect it's just a remake of a PMS5003 with longer lasting laser and fan.

@petewill said in What did you build today (Pictures) ?:

@berkseo nice! What did you use for the capacitive sensor? MPR121?

TTP223s in top left and top right corners

@berkseo I'm curious about that, why not use the capacitive touch function of the NRF52832 ?

@fotofieber said in What did you build today (Pictures) ?:

EDIT: ordered a MHZ-19 for the tests

Make sure you order a MHZ-19B, it uses less power and has fixed an autocalibration problem.
SenseAir S8 has a better calibration process using several days, so if you don't ventilate your room during 24h it will not use a wrong reference level and report wrong values.

And about BME680 there are boards on AliExpress with included STM32 Cortex M0+, basically it's the same than the MiCS-VZ-89. Search for GY-MCU680V1.

@sundberg84 you should print the board on paper, stick it on a piece cardboard and cut. Then check if size is good, you can even put the "big" components on it by sticking the pins through the cardboard to make sure you'll have enough space.

@fotofieber said in What did you build today (Pictures) ?:

Testing a CCS811 CO2 sensor.

Unfortunately this is not a CO2 sensor. It's only a VOC sensor giving an estimated eCO2 value. It's useful to tell you if your room needs ventilation, but not much more. And as even the VOC part is not calibrated it's only good for relative measurement.
AFAIK the only similar sensors which are calibrated and give absolute values are SGP30 and BME680.
If you want to measure CO2 you need a CO2 sensor and it's going to consume a lot of power, at least too much for a battery powered sensor.

[edit] there's also the MiCS-VZ-89TE TVOC sensor, they claim to have a curve of eCO2 not too far from NDIR sensor in their datasheet. But that datasheet is strangely poor in details, they didn't even put any electrical characteristics...
https://sgx.cdistore.com/datasheets/sgx/MiCS-VZ-89TE_V1.0.pdf

Congratulations @BearWithBeard, that's a great achievement, especially from someone supposed to be a "novice". I'm sure many can learn from your lessons, the most important one to me is "don't rush it", it goes with "triple check schematic then board", "unit test your components" and "don't finish late at night". Else you will probably end up with mistakes on PCB and a lot of wasted time.

For reverse polarity protection, I think this is the more simple solution:
https://forum.mysensors.org/topic/5478/how-to-get-longest-battery-life/25

I agree with @Omemanti above. Go for NRF52832, for MySensors projects it has plenty of memory, you don't need to double it. If you use a regulator like XC6206 to regulate to 3.3V and use DC-DC it won't be less efficient than the regulator in nrf52840.

For the modules I like the Fanstel because they have a good antenna design, and similar footprints between different versions, so you can use the same PCB and short/medium/long range modules.
But EBytes module do the job for a low price, they are also often discounted, they sold them below 3$ at some points, so like @Omemanti I have some stock