Building my own greenhouse data logger

Electronics, Gardening and Lifestyle

Building my own greenhouse data logger

April 1, 2019 DIY Gardening 0
greenhouse data logger cover image

A bad back threw out the opportunity to get digging in the greenhouse this weekend. Rather than sulking i ended up throwing this nifty little greenhouse data logger together. This will be a fun little project to develop over time and on those days i can’t get out into the garden. (currently 6 of 7 😣) Eventually i’d like to be able to log on to view the data and even maybe have a camera setup in the GH to check in on my babies…. this could grow more out of control than the tomatillos i planted last year.

Anyway this is what I’ve done so far, and I’ve been too excited to not share it with you all!

nwemos d1 pro greenhouse data logger


What the greenhouse data logger is (currently) composed of.

  • Wemos D1 Pro ESP8266 micro controller.
  • Micro sd card slot to record data to (8gb card, enough for years of data)
  • Real time Clock module for time stamping (and scheduling watering in the future)
  • 2x DHT11 temperature and humidity sensors.

This is only start though and no doubt i will move to a bigger micro controller, as no doubt ill run out of pins before i have all the sensors and features i want out of this little Wemos D1 pro board.

dht11 sensors adding cables for greenhouse data logger

The bare DHT11 Temp/Humidity sensors are super cheap and accurate enough for what i want just needs cables.

dht11 cables on and ready to install

20 minutes later cables on and covered ready to install, better yet everything for this project where items already in my possession so it hasn’t cost a penny! 😬


installing my greenhouse datalogger

Quick and dirty install, internal sensor is in the white tube to avoid direct heating, it’s also currently powered via a USB port on solar controller until i finalise the most efficient way to power it, Any tips?

checking the sensors are reading ok and saving to the greenhouse data logger

Once it was installed i plugged in the laptop to check it was reading data, the unit is wifi enabled so ill be adding in some wireless integration over the coming weeks.

greenhouse data logger power issue

Hmmm something is draining the power more than expected…. more testing required. 👎


arduino IDE greenhouse data logger code

Trying to trouble shoot some coding issues, deep sleep mode worked so good it wouldn’t wake up. 😂

I ended up having to pull it out a few times to tweak code as its a mash of different sensors and the libraries required to run them, i ran into a few problems that were a PITA to find and fix due to the very poorly wrote code and copy and paste work from individual tests of the components.

So this is one of the first things i need to sort, clean up that code..

I did however manage to pull some data and put it into a graph. I’ts only 3 hours worth but i’m looking forward to have more to look over and see how things change over the coming weeks. Especially once i start finishing other elements on the greenhouse.

external sensor test data graph

internal sensor test data graph

Quick sample of a 3 hours data shows some areas for improvement


How i’m looking to improve the Greenhouse data logger.

  • Clean up code of ease of trouble shooting/data formatting.
  • Add in some averaging to avoid erroneous data.
  • Work on a way to reduce power usage.
  • Add in additional sensors (Light, Rain, soil moisture etc)
  • Maybe Separate the data in to Day/night or daily logs for analysis and protecting data encase of data logger issues.
  • optimise position of sensors or improve covers to avoid radiation heat influencing readings (if you look at the graph you may see a issue)

Once I’ve got something stable and the code laid out like i want it i’ll be doing a guide on it and happy to release the code etc if its of any use to you lovely folk.

Question – What data would you love to know from your garden??? it’d be great to get some ideas on what other functions i may add over time.

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All the best





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