Category: Making Stuff

Soil moisture sensors are finally working again

I purchased a couple of LoRa data loggers and a LoRa gateway from Seeed Studio probably more than a year ago.  I liked these data loggers because of the quality of Seeed products, great customer support, reasonable price, and that they could each accept two analog inputs.

The analog inputs allowed me to add Vegetronix VH400 soil moisture sensors, which I’ve been impressed with from past use in a WiFi irrigation system I built.  Moving to LoRa isn’t necessary, but as far as that goes, neither is an automated garden irrigation system! 

Part of the appeal of the Seeed system is that they have a Home Assistant integration where I can set the gateway up using Chirpstack to transmit the data to my Home Assistant system and access my sensor data for data logging and irrigation system control.

This worked in my test setup for several months, but after a Home Assistant update, it stopped working several months ago. At least I thought it had.  I posted an issue about this on Seeed’s github page but never really got a good answer.  I’m not blaming them… they don’t have to make integrations just to satisfy my needs, but it was disappointing that it didn’t work.

I checked all of the settings in my Home Assistant setup, even reinstalled everything (three times!).  No luck.  I next tried a fresh install of everything on a different Rasberry pi (Home Assistant runs on a pi).  Still no luck.

Going back through Seeed’s installation wiki, It said to check the gateway to see if it was transmitting.  I logged into the gateway and it was. I then checked to see if the pi was getting data in the MQTT broker in the Home Assistant setup.  It was too. I was on to something!

I dusted off my Node-Red skills… well, not so much skill as tinkering. I haven’t used Node-Red as much as I used to since I don’t build (solder and program) as many microcontroller sensor and switches as I used now that Home Assistant has so many integrations and the automations have improved so much.  Anyway, with the help of ChatGPT, I was able to bring the data in via MQTT, parse it for what I needed, format it to be recognized as sensors that MQTT could discover, and bam! It works. 

I set up a simple dashboard and can now see and log the data.  This is just an indoor set up for now.  No control or output to a database. Rather, it is the first step in rebuilding BBAGIES (BrummBilt Automated Garden Irrigation Efficiency System) v3ish.something.  BBAGIES will allow me to monitor four zones in my garden and control a pump from a IBC tote to turn the system on when a moisture level threshold is reached and off when the moisture level is sufficient. This will be on a zone-by-zone basis. I’ll have to establish the moisture level thresholds. I’ve tried calculating a moisture percentage in the past, but in reality, the raw data from the sensors and my experience and observation will let me set these thresholds.

More to come (if I can actually make myself sit down and write and post blog updates)!!

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It’s Science Man

More tinkering for Garden 2023

January 21, 2023

I started seeds for the 2023 garden three weeks ago. Just peppers and tomatoes. Old peat pellets were in the garage, so that’s what I used initially. As much as I loathe peat pellets, they’re what I had. A week ago I started more in some “fancy” starter trays I found on Amazon. This blog isn’t about either of those, but it is about a new idea I have.

I found these net pots on Amazon. They appear similar to the netting around peat pellets… supposedly biodegradable, but I doubt that. Doesn’t really matter since they’ll tear off easily when I go to transplant plants to the garden.

I’ve been using plastic stakes and a sharpie to identify what’s what in each starter cell/pot, but that is tedious and the stakes are difficult to stick in the soil and get to stay in such a small container. I thought there had to be a better way.

Then I remembered I had ordered these NFC tags to tinker with in Home Assistant, but haven’t really used them, so I thought, “hmm, lets make something I can just scan with my phone to see “what’s what in the pot” (I made a rhyme!).

Here’s a brief description/how to (pics below):

  • Install a NFC reader/writer on your phone. I use NFC Tools from Wakdev on my iPhone. *note: your smart phone needs to be NFC-enabled (be able to read/write NFC tags)
  • Open the app and you’re ready to start
  • A menu will pop up. Select “Write”
  • Another screen will pop so you can “Add a record”. Click that.
  • You’ll have a lot of choices of format, but for this, I just used “Text” to put in the plant name and date
  • Hit OK
  • Hit “Write” and you’ll be prompted to approach the tag (hold the tag near the reader on your phone)
  • It’ll let you know the tag is written — you’ve created your first NFC tag!
  • I then placed the tag under the fold of the net pot I’ll plant in. Seems to hold pretty well.
  • You can then open NFC-Tools and hit “Read”
  • Approach the tag (sounds pompous doesn’t it) and a screen will pop up showing a lot of info about what’s on the tag. you want to scroll all the way to the bottom and you can see the text you put in.

This is pretty basic, but works for proof of concept. I’ll look for a better app that doesn’t require as many steps or have as much noise to read the tag info. I think I can find a way to use it in Home Assistant, maybe with Node-Red, or maybe I’ll even build my own NFC tag reader (either are very likely to happen… someday!).

It’ll be interesting to see how they hold up and if moisture will affect the ability to read them, but for now it seems to work.

As always, I’m enjoying the tinkering with making BrummBilt garden tech as much as (probably more) than the actual gardening itself.

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Screw Printing Project Boxes!! (when you don’t have to)

I enjoy designing project boxes in Fusion 360 for my tinkering, but man do I hate waiting on them to print.

I’ve got lights and mounting hardware ordered for my permanent Christmas/holiday lights as well as a couple of other odds and ends I’ll need to get them installed.

One thing I do already have is is the Dig-Uno controller set up with WLED, but needed to get an enclosure made for it. I’ve been playing around with printing a custom enclosure for it, but never could really get the holes on the Dig-Uno to line up.

I dug through my “toy box” and found a couple of nice project box I had bought for who knows what, but figured why not use them for this (since this will be my most expensive non-garden project to date – only the best right?)

I measured the mounting hole spacing on the inside, got the hole spacing fo Dig-Uno close enough and got the Dig-Uno mounted in the box. This is a sealed project box, and I really don’t want a lot of heat build up in the box, so I drilled out a vent hole in the lid, mounted a heat sink on top of the D1 Mini and printed a custom vent cover (image at top of this post).

Once I get the mounting position and orientation figured out, I’ll drill additional vent holes in the side of the enclosure.

Oh, and my table, as usual is a mess. Fortunately, the only thing I spilled everywhere was the box of heat sinks!

Parts:

Lighting Stuff on Order:

Will post more on this project as it proceeds…

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KIL’N IoT

“Kil’n It” or “Kiln Iot” (Kiln Internet of Things)

A friend of mine throws a little clay (does pottery) and has a used electric kiln with an analog meter on her thermocouple (device used to measure temperature in the kiln).

Based on my tinkering hobby, I thought a great project would be to build a digital, WiFi enabled, temperature sensor that could be plugged into the kiln’s thermocouple so she could have a digital display and be able to monitor it on her phone.

In my home automation projects, I’ve used inexpensive sensors (DHT11, HT221D, BME280, etc.) to monitor temperature and humidity in different areas of my house, patio, and shed

Photo of different temperature and humidity sensors.

using NodeMCU and D1 Mini microcontrollers.

Based on my home monitoring I knew a kiln monitor could be done, but I’m measuring temps in livable environments (though it does get hot here in Texas!).

The challenge is that the sensors I use would burst into flames if you put them in a kiln! That’s why thermocouples are used in kilns… they can handle a couple thousand degree (oF) temps.

I learned that you need an amplifier to pick up this signal from the thermocouple and transform it into something a controller (with the right firmware (software)) can interpret into a temperature reading.

There are different types amplifiers (just google something like “thermocouple amplifier board”), but I went with the MAX31855. You can find breakout boards with this chip on them from a few different suppliers on Amazon.

The one I went with is from Adafruit, a NYC-based company that was only a couple of bucks more expensive than the others from companies I don’t know by name. Side note, I often buy electronics components from these unfamiliar companies on Amazon, including the controller I used in this project and the quality is often good enough for my tinkering, but if you want definitive quality, go with Adafruit.

For this project I went with Adafruit because I knew the quality of this new-to-me board would be excellent and well worth the couple of dollars more.

In the first iteration of this project, I soldered female headers to a printed circuit board so I could mount the controller (NodeMCU) and MAX31855 breakout board.

I then soldered the pins from the controller to the header for the amplifier board and connectors for the OLED display (SSD1306) (soldered wires are on the underside of the board in the pic below). I wired a thermocouple wire to the amp and was ready to program the controller.

At one point in my home automation adventures, I had the wild idea of learning to code so I could write my own programs. Through google and YouTube, I learned enough to put together some rudimentary programs that kinda worked, but I quickly realized that I was more interested in making things that work rather than getting behind the curtain and making the stuff (software) that makes stuff work. That’s when I discovered Tasmota, an excellent open source software that works with the controllers I use and can be customized for different applications. I’ve been using it almost exclusively in my projects since.

I downloaded Tasmota 8.1 for this project (the newest version at the time). In many cases, you can just flash the the precompiled binary (bin) file to the controller using a flashing tool like NodeMCU Pyflasher or Tasmotizer, but displays and the Max31855 aren’t supported in the base bin file (tasmota.bin).

This leaves a couple of options. You could flash the base bin file and then the sensors bin file and and then the displays bin file. The problem is these bin files can be pretty large (relatively speaking) and may not flash properly. You could try the lite version of the base bin file, which is pretty bare bones, and then try flashing the other two, but you may run into problems with that too.

That’s why I prefer to go a different route. I download the full Tasmota program and edit it in Arduino IDE (more recently PlatformIO). Though I’m no programmer by any stretch of the imagination, I have picked up just enough to understand a few things when looking at the Tasmota code (which is well documented throughout!).

In Tasmota, I can go ahead and set up my WiFi access (SSID and password to connect to a home network) and MQTT (so it can communicate with my home automation system (Home Assistant – another open source system that runs on a Raspberry Pi).

In Tasmota, I found the code for displays and uncommented those lines as well as uncommented the line for the MAX31855 sensor. Note: you’ll do most of the editing in the my_user_config.h file. See Travis’ (digiblurDIY) youtube video for an excellent tutorial. It is in PlatformIO rather than Arduino IDE, but the steps are basically the same, and he cleans the file up much better than I do to further reduce the size by disabling things he won’t be using. Note also that I did make one other change related to the SSD1306 display that I’ll explain in a bit.

I was then able to upload the firmware via Arduino IDE, and the controller was ready to set up.

I found the IP address of the controller since Tasmota made it discoverable on my home network. It’ll be in format of something like “192.168.1.12”, but the numbers from your network may vary. I use the Fing app, but you can log into your home router and find this too. Another way is to watch the serial monitor in Arduino IDE and it’ll show the IP address when the controller boots up.

I the put my controller’s IP address in a web browser and it connected to the controller via WiFi so that I could set up the display and temperature sensor (oh yeah, you have to first change the module type to “Generic” under the Configuration).

My SSD1306 display is an I2C device , so in the Tasmota web UI, I set GPIO4 to SDA and GPIO5 to SCL. Note that for my particular SSD1306, I had to go into the xdsp_02_ssd1306.ino file using the Arduino IDO and change the line “#define OLED_RESET 4” to “#define OLED_RESET -1” because Tasmota uses the Adafruit SSD1306 library which is designed for their SSD1306 that has the reset on pin 4. My particular display doesn’t use a reset pin, so I had to change it to -1.

The MAX31855 is a SPI device requiring three pins (Note: in Tasmota, it’s a softSPI rather than hardware SPI, so you don’t turn on (remove the backslashes before) SPI in the Tasmota code when editing it). In my application, I use GPIO12 for CS, GPIO14 for CLK, and GPIO15 for D0.

Once I set those up and restarted it, I was getting temperature readings through the Web UI from the thermocouple I had attached to the amplifier board. The pic below is a template and has a couple of of other features enabled.. read up on Tasmota if you want to know how to do templates, but the look is essentially the same as you’ll see using the Generic Module.

To get the display to work, you have to change some settings in Tasmota. Go to the Console in Tasmota and enter the following (without the quotation marks):

  • “DisplayModel 2”
    • This sets it up for a SSD1306 display
  • “DisplayMode 0”
    • So you can get the temperature reading as text to display
  • You’ll also have to adjust the size of the text, and I created this Rule in Tasmota to do that (use the console for this too)
    • Rule1 on tele-MAX31855#ProbeTemperature do DisplayText [f2p7x15y20]%value% F endon

Check out this link for more on Display commands in Tasmota.

From here, you can see the temperature on you computer or phone (I bookmark the Tasmota IP web portal for easy access) and turn the monitor on an off using the “Toggle” button. I’ve recently found the Tasmota command: WebButton Display On/Off (or whatever you want to call your web button instead of “Toggle”… just put the name after WebButton1 in the console command line).

Once I had the controller set up and working I designed an enclosure (pic at top of this blog) in Fusion360 and printed it on my Ender 5 3-D printer. This took me way too many prints to get it how I wanted it, largely because I was still relatively new to Fusion 360 at that time. I won’t go into detail on my enclosure design, but feel free to contact me and I’ll be glad to share it with you… I’m working on tweaking that currently.

I did take the finished project over to my friends house and got it hooked up to her thermocouple and see the temp on the display. Unfortunately I wasn’t able to get it to connect to WiFi since where she has her kiln is in a building away from the house and they use a WiFi extender that I haven’t figured out how to work with in Tasmota yet. Maybe set up as the second access point??… other Tasmota users let me know your thoughts if you know how to do this.

She was nice enough to set me up with some free home brew (she and her husband make great beer… that Quad was incredible!), and black garlic (check out her company The Black garlic Company).

I’m still pretty pumped about making this kiln monitor since it was more complex than my household sensors I’ve made in the past. The free beer and black garlic just put the icing on the cake!

Here are some things I’m working on for version 2:

  • Use D1 Mini instead of a NodeMCU.
  • Use mini connectors so it’s easier to connect and disconnect the thermocouple (or connect a different thermocouple (for brewing or monitoring fermentation temps for example (though there are different sensors that are less expensive and easier to set up than a thermocouple).
  • Use a printed circuit board with pin holes in parallel by row (makes soldering wires from controller pins to the display connectors and amplifier header easier). Ideally, I’ll put my big boy pants on someday and design a custom PCB.

I may update this blog post from time to time, but feel free to reach out if you have any questions I may be able to help with.

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