Datalogger connected to gas sensors

Development Boards Artemis
1

I am writing to request your assistance regarding your product “OpenLog Artemis”, specifically on how to connect it to a third-party sensor.

Context:

Our laboratory is currently developing a gas measuring instrument. In the final stages of its development, we came across your product which might offer a tremendous improvement for the data logging aspect. For that, we have recently purchased an OpenLog Artemis data logger to try to incorporate it into the instrument’s functioning but we stumbled upon a major problem: we cannot get the OpenLog Artemis and our hydrogen sensor module (EC Sense TB-600C-H2) to communicate.

What we know:

Our instrument containing only one sensor module, we understood that it is possible to solder the sensor’s physical cables directly to the TX, RX, 3V3, and GND ports of the data logger. Moreover, we know that communication with the data logger, which includes uploading scripts and sending commands, can be done via the Arduino IDE software. We are also aware of the fact that our sensor module transmits digital data (not analog) using the Serial communication protocol. In addition, upon research on the internet, we also found a GitHub page containing all the data logger’s firmware “.ino” scripts as well as a short tutorial on how to add a new sensor to the system (for Apollo3 v1.2.n). However, we found that the codes are extremely complicated and are reserved to adding sensors made by your company.

Question:

That being said, we would like to know if the use of a third-party sensor module is at all possible with your data logger, and if yes, the best and most efficient way of doing it.

Please find attached the sensor module’s technical specification sheet which contains the communication protocol, and below the GitHub links where we found the tutorial as well as the firmware “.ino” files respectively:

https://github.com/sparkfun/OpenLog_Art … SENSORS.md

https://github.com/sparkfun/OpenLog_Art … og_Artemis

If you are able to help us, please contact us via this email address. We appreciate your help and thank you in advance for your time.

Yours faithfully,

2

If your sensor is already outputting TTL serial, you shouldn’t need to do anything but enable serial logging on the openlog at whatever baud rate your sensor is using and connect the two devices.

If you need something that controls the sensor as well, that could get a little tricky.

3

Thank you for your reply.

Our problem is that the sensor’s manufacturer specifies a few lines of code to “translate” the data received by the data logger to give us the desired values (gas concentration in ppm, temperature in Celsius, and relative humidity in %).

From what we understand, we ought to “inject” these lines of code into the data logger’s firmware, which we are currently trying to do, so far without success. I was wondering if you would have insights on the matter.

Sincerely.

4

It might be easier for you to use something like a arduino pro mini to inject your commands and then use the openlog artemis to log the results rather than modifying the openlog firmware.

5

If the sensor data are already human readable ASCII characters, consider scaling the data to desired measurement units after the logging operation. The program that reads the file can apply the scale factors.