Environmental sensor recommendations

[texaspyro]

I recently added support to Lady Heather for reading environmental sensors.  The code supports up to four values (humidty, pressure, and two temperatures).   The sensor can be used either the main input device or in conjunction with any of the input devices that Heather supports. 

There are a gazillion and 3 environmental data loggers out there, but 99+% just log data for later analysis (no good) or use custom programs or smartphone apps.   There seem to be very few devices that can be controlled by an arbitrary program. 

The code currently supports the USB-xxx devices from dogratian.com or the LFSxxx devices from LookingForSolutions.com.  It also has support for a yet-to-be-built-by-me device that is customized for Heather/metrology.

I am looking for recommendations for other devices to support.   THE requirement is that they can provide measurement data, in real time, via a serial (or virtual serial port) or Ethernet interface.  They CANNOT be dependent on some proprietary driver or interface or program or app.   They need to be able to either stream readings (best) or be polled for readings by sending some command to it.  If the temperature sensors could be remotely mounted, that would be a big plus... that way you could monitor a couple of points inside a piece of equipment.

So far the Dogratian USB-PA seems to have the best bang for the buck.  It's main issue is that the readings get updated every five seconds.   1Hz would be a lot better.

[ManateeMafia]

I have a RPi and BME280 setup to act like a Fluke 1620A. You telnet commands to it via ethernet and it will respond with a comma delimited string of the three values.

It also has a small LCD that displays the readings. I have been using it for 18+ months collecting data from my 10V refs. I can share all of it with you through ftp on xDevs. The initial cost may be high but having the linux + python is easier than having to hack some proprietary device.

[cellularmitosis]

Si7021 is my current go-to.  BME280 will also do pressure.

https://github.com/cellularmitosis/logs/blob/master/20180304-1590b-isothermal/Arduino/ambient/ambient.ino

https://www.ebay.com/itm/Si7021-Industrial-High-Precision-Humidity-Sensor-I2C-Interface-for-Arduino/201539848414?epid=808991786&hash=item2eecb608de:g:d2gAAOSw8w1X6zIv

Note that the BME280 units on ebay aren't compatible with the Adafruit Arduino library, you need to use this one instead: https://github.com/finitespace/BME280

https://www.ebay.com/itm/Breakout-Temperature-Humidity-Barometric-Pressure-BME280-Digital-Sensor-Module/401000227934?epid=12017746612&hash=item5d5d79e45e:g:bnQAAOSwmRFafX1V
 
ClosedCube on Tindie also has a bunch of env sensor boards: https://www.tindie.com/stores/closedcube/

Edit: I should also note that the Si7021 is a bit noisy.  If you are trying to regulate something down below 10mK, you can get better results with a thermistor.

[texaspyro]

I'm not looking for chip breakout boards.   I'm looking for completed devices other people can buy off the shelf.   

The board that I am going to build will use a BME280 and a couple of thermistors.  Maybe also a couple of extra ADC channels.   It will also support Heather's temperature control features.

[TiN]

If you need PCB layout help, let me know. I was thinking to build own dedicated THP monitoring for homelab, but never got to it.
With your great software, it would be good enough motivator to actually do it. I recently got 7" Pi TFT so will be getting Lady to work on it with my Rb LPRO with RPI3 soon

[texaspyro]

I recently got 7" Pi TFT so will be getting Lady to work on it with my Rb LPRO with RPI3 soon

I recently laid out a board to connect am LPFRS to my BNC/SMA connector board.  It can also be used with an LPRO.  It includes a 1PPS generator with buffered ACMOS output,  EFC reference voltage generator/pot, and a PICPET 100 ns res timestamping counter chip.

For the environmental sensor board I'm looking at the BME280 and an ADS1115 4 channel 16-bit DAC (for thermistors, etc... I wish the ADS1115 had a reference voltage output for driving thermistors... I will probably use an LM4040).   The board would output readings every second.  They would be the average of all the readings taken over that second.  The averaged ADC readings would be semi-effectively 20 bit.

The temperature control system would either use the 1Hz PWM output that Heather can produce on the serial port modem control lines or a 15 kHz 16-bit PWM output generated by values sent to it via the serial port.   The 15 kHz PWM would also be filtered and output as an analog value.

Attached is a plot of Heather monitoring a Thunderbolt and a USB-PA environmental sensor.  The first two plots are the Tbolt's DAC and TEMPERATURE values.  The last three are the USB-PA.

[texaspyro]

I'm looking at using a REF200 dual 100uA current source chip to drive the two temperature sensors.  It is spec'd at .5% accuracy and 25ppm/C.    That should allow around a 0 .. 100C range with 10K thermistors if the REF200 was driven with 5V.  At 0C the thermistor would be dissipating 0.3 mW.   With the ADS1115 ADC programmed for max gain a PT1000 sensor can be read out.

Does this seem like a reasonable implementation?   Any major gotchas?

[awallin]

There are a gazillion and 3 environmental data loggers out there, but 99+% just log data for later analysis (no good) or use custom programs or smartphone apps.   There seem to be very few devices that can be controlled by an arbitrary program. 

I've used a Papouch temperature + RH (+ dewpoint) Ethernet sensor. It has a web-page from which I parse the relevant values with a simple python script.
https://www.papouch.com/en/shop/product/th2e-ethernet-thermometer-hygrometer/

100-150eur might not be dirt-cheap for hobby-purposes...

[texaspyro]

I got in a lookingforsolutions.com LFS104BW USB sensor in and have Lady Heather working with it (also probably works with all their LFS10xy series devices, but I don't have any of those to test the code with). 

The LFS104BW is rather interesting with way too many features than needed.   It outputs humidity, pressure, ambient temperature, and IR temperature.  The values update at up to 2 Hz (vs 0.2 Hz for the USB-PA).  The sensors are not as accurate as the USB-PA and the resolution is not as good. 

Overall it seems like a very nice device for around $75 if you need wifi,  web server,  alarms, email,  IOT cloud suport, etc.  I bought it mainly because it had two temperature outputs and I wanted to test Heather's support for that.

https://www.ebay.com/itm/Infrared-Ambient-Temperature-Humidity-Bar-Pressure-to-USB-WiFi-Alarm-output/273164530898?hash=item3f99dff4d2:g:sO8AAOSwZVJarXTO

[MegaVolt]

Here is a device for issuing temperature, pressure and humidity. With rich libraries and settings.

http://www.yoctopuce.com/EN/products/usb-sensors/yocto-meteo-v2

[Bad_Driver]

Hi

I jump really late into this discussion. I‘m using with different sensor EasyEsp. In the case of the attached image it reports data from my garage. And it reports the datas via WiFi and/or USB-Serial to the host.

Since configuration and calibration with EasyEsp is very easy it would be a perfect supported device for LH.
You can set it in a view minutes.

I‘m a late but grateful user of LH! Thanks again for this helpful tool!