Temperature/humidity device


#1

Since I figure this is a basic device that many will want, is there someone working on making it happen ?

I am thinking an onboard temperature/humidity sensor, with a connector for an external one, maybe only external temperature, maybe using DS18B20 probe.

Access to a few ADC/IO pin terminals would be a plus.

Powered by a few AA(A) or coin cells with 6months-1year lifetime.

And of cause without taking up too much space :slight_smile:


#2

Are you looking for a fully packaged device that does this? Or just want something that is functional?

The simple solution is bluz with a battery shield and the Proto shield, you could solder whatever you want on there. But it may not meet the space requirements.


#3

A completed device to save me from doing it myself, but maybe its too simple to make a viable stand alone product.


#4

@MORA
My Bluz’s are still to arrive, nevertheless I use BME280, HTU21D, MPL3115A2 and DS1820 myself with Photon’s and Duo’s and plan to do the same on Bluz.
Best thing to do is to make sure that the sensors are mounted away from the controllers or that you put the controllers to deep sleep for 5 minutes and than run a measurement.
Once I have my Bluz’s I’ll give it a try.

Rudy


#5

I’ve tested the DS18X stuff and can tell you that you’ll need to knock down the precision a bit. I’ll be publishing a lib on the Particle Build IDE with examples of doing this. Anything higher than 10-Bit and hardware interrupts get in the way. Never did get DHT working but I’m sure someone will!


#6

Does your demo code wait for the conversion to complete ?

If the DS18B20 uses a pullup resistor instead, you could start conversion, and read the result a second later without having to active delay for it.


#7

@eric, what is the operating temperature for bluz? Can bluz be used to build a temperature sensor for applications such as cold rooms, fridges and freezers?


#8

@LukeUSMC and @eric, could you tell me the name of the library you published on Particle Web IDE?

Thanks.


#9

It doesn’t look like @LukeUSMC’s library was ever published to the Web IDE. However, you can include his changes into the DS18B20 library that is already there or simply create new files in your build and copy in the source code.

I will try and see if we can get this into the IDE somehow, either as a PR into the original library or as a new one. That may not happen immediately, however, so it may be best to use the options above in the shorter term.


#10

Adafruit BME280 community library (available on WebIDE) is not working with Bluz.
I used the original example code except additional of
Particle.publish("Temp is", String(bme.readTemperature() ));
I am getting the value like 172 degC.
Removed the sensor and tried immediately with Photon.
I am getting the accurate values form Photon.
Can’t figure out what the error is on Bluz…

Update : followed this topic. Temperature is showing as 28.5 something degC. Will test other parameters and update here.
https://neighborhood.bluz.io/t/solved-i2c-problems-with-bluz/500

Another update : Nah… It is not working properly. Values are really off.:persevere:

Final Update ( Hopefully :3 ) : Modified the official Adafruit library based on Particle compatible BME280 library. Data are coming good.


#11

Glad it is working!

If you would like to publish that working library in the IDE, that would be great! Alternatively, if there is a specific change to make it work, you could send a pull request to the original author. We would love to get more libraries in the IDE compatible with bluz, so if you have a working one, that is a great start!


#12

I’d also like to hear what you changed. I just got one of those sensors and plan to try it out this weekend.


#13

@Fragma There are a few changes which I don’t remember. But basically I disabled (commented) the library codes which relate to SPI class because those codes gave the compilation error.

Update : I DM-ed the library to you.


#14

Hi, good that you got this going, great job. I 'm also interested in this library, can you also send me a copy ?
Kr


#15

Since I am not quite familiar with Github, I forked the official library and did the necessary changes.
Please make sure to read the read me file first.
Hope it helps.

https://github.com/phyotz/Adafruit_BME280_Library


#16

Works great, thanks.
FYI, according to the docs, for accurate altitude you must “…know the hPa pressure at sea level for your location and day”, I used this to get mine: http://weather.unisys.com/surface/sfc_con.php?image=pr&inv=0&t=cur


#17

In order to get hPa, do we have to read the value from color?
Lets say for the region with cyan contour, it has 1014 mb.
Followed by conversion of that 1014 mb to hPa ?
Is this the way?


#18

Enter your zip code in the upper right and then use the pressure listed for your area, it will be roughly the same as what you see on that graphic (ie: Pressure(alt): 1025.1 mb (30.28 in)). I don’t believe a conversion is necessary, I just entered the mb directly and my altitude is more accurate now. My readings are still off a bit but I just soldered my sensor and I’ve heard that may impact the readings for a few days.


#19

Didn’t aware that 1000 hPa = 1000 mbar. :joy:
Thanks.
I shall try out altitude measurement after firmware update to v2.1.50.