SenseLoRa by Makerfabs: Plug and Play IoT for Greenhouses

If you've ever wanted to set up a wireless monitoring system in your vegetable garden but were discouraged by the complexity of creating a remote, solar-powered, water-resistant setup, the SenseLoRa system from Makerfabs could be just what you need. It offers all those features while being completely plug-and-play, requiring no configuration effort. In this article, we test the SenseLoRa Industrial-grade Air Monitor and the LoRa Receiver to see if they truly deliver on their promises.

It was a warm and sunny day when I decided to try out the SenseLoRa system from Makerfabs. My setup consisted of a SenseLoRa LoRa Receiver and the Industrial-grade Air Monitor. A third unit exists too, the SenseLoRa Industrial-grade Soil Remote Monitor, but I didn’t have one.

A quick look through the online documentation showed me that I was dealing with some kind of plug and play environmental monitoring system that didn’t need any configuration. So, I connected the receiver through a USB hub to a laptop computer. I put its antenna outside, stuck with its magnet to the metal roof of my workspace. Then I opened the Air Monitor box to switch it on (the power switch is inside), closed it again and put it in the front yard (hidden by the house, so no line of sight or LoS), about 25 meters away from the receiver. When I returned to the receiver, it already displayed (JSON) data that was sent by the Air Monitor:

Num:1 | -80dbm

{"ID":"AirM01",

"COUNT":2,

"SLEEP":3600,

"bat":3.90,

"Temp":28.38,

"humi":62.62,

"eco2":400.00,

"lux":189.17}

Plug and play indeed!

senselora receiver — Figure 1: The receiver has a small display that shows received data in JSON format.

Note the low light level (‘lux’). This data was probably collected when I was preparing the unit or holding it in my hand.

Air Monitor

As you can gather from the received data (temperature, humidity, eCO₂, and light intensity), the Air Monitor is intended for use in greenhouses. However, it might be useful too in classrooms and other spaces where people meet, as it can tell you when to open a window or when to switch on or off the lights. In case you like the concept, but not the sensors, know that these can be replaced by other sensors with an I²C port. Of course, you will have to adapt the software (open source) to accommodate other sensors.

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ESP32-S3 with RF92

The Air Monitor consist of an ESP32-S3 connected to an RF92 LoRa module from HopeRF and an I²C bus to which three sensors are connected:

SGP30 air quality (equivalent CO₂, i.e., eCO₂, 0–1000 ppm)
BH1750 ambient light (1–65535 lx)
AHT10 temperature (−40 °C–80 °C, ±0.3) and humidity (0–100%)

The device can be configured over Wi-Fi when you put it in AP mode. This lets you change its ID (practical when the system comprises several Air Monitors) and the transmission period.

The Air Monitor has a 1000 mAh rechargeable battery inside that is charged by the kit's solar panel and that keeps it running during the night.

Industrial Grade?

The Air Monitor is labelled Industrial Grade, which probably refers to its IP68-rated enclosure. It comes with a 6 V, 6 W solar panel with a mounting bracket, nuts and bolts, and an antenna (1 m cable). The antenna looks like an indoor device and only has a magnet in its base for sticking it to some metal object. According to the user manual, it is suitable for outdoor use. The mounting bracket made of painted (enameled?) iron will probably not last long outside. But then again, the Air Monitor is intended for use inside greenhouses (where iron doesn’t rust, that’s a well-known fact).

senselora transmitter — The SenseLoRa Industrial-grade Air Monitor mounted outdoor on a wooden structure at a height of almost two meters.

The LoRa Receiver

The LoRa Receiver comes as a small module consisting of a red PCB sandwiched between two transparent acrylic plates. It is based on an RP2040 microcontroller and has an OLED display, microSD-card slot (a 16 GB microSd card is included), a HopeRF RF96 module and a USB connector. This is the part I like the least. The USB connector is a male A-type, turning the module into a large dongle that you are supposed to stick into a computer. This severely limits its placement unless you add a USB hub. Furthermore, the module is quite wide (34 mm) and high (18 mm) for a USB stick, and so it will probably block access to other ports of the host device.

To keep the display readable for most mounting situations, a pushbutton (‘TFT’) is available to rotate it by 180°. An option to switch it off would have been welcome.

The antenna is of the same type as the one for the Air Monitor. Its long cable (5 m) is practical, and so is its magnet if you have a metal surface to stick it on. If you haven’t, you’ll have to use adhesive tape or tie-wraps or something to fix the antenna.

Endless Data Logging

Besides displaying the incoming data, the receiver also transmits it verbatim over its USB serial port and stores it on its microSD card (if one is inserted). Interesting is, at least that's what I thought, that it keeps appending to the same log file on the microSD card, even after a power cycle or reboot. The file is not overwritten or recreated at boot time. Therefore, any existing data is not lost unless you delete it deliberately. Note that when recording the serial port data, you may also capture boot and status messages when the TFT button is pressed. These may break a simple data converter script. A Python script for recording and decoding data is available at the Makerfabs GitHub repository.

senselora receiver for real — This is how the SenseLoRa receiver ended up in a real-life logging application.

Very Hackable

Both the Air Monitor and LoRa Receiver are very hackable devices. The schematics, board design files (Eagle) and source code are all published on GitHub together with the user manual. The LoRa Receiver is built around an RP2040 microcontroller while the Air Monitor is equipped with an ESP32-S3 module. Both are well-known microcontrollers in maker land. The software is Arduino based, making it easy to adapt it to your needs and desires.

temperature 1838 hours — Almost eleven weeks of continuous temperature logging, one sample per hour. I had hoped for a warmer summer :-(.

Conclusion

With the SenseLoRa concept, Makerfabs has tried to make LoRa easy to use for point-to-point connections. Configuration of complicated LoRaWAN and cloud services is avoided this way. The system is plug and play and works out of the box simply by switching it on. Extending the system is possible with minimal configuration (only the device ID must be set). Its simplicity makes SenseLoRa practical for quickly setting up a greenhouse monitoring system. However, what will happen when your neighbor decides to do the same is unclear.

Even though some parts are said to be industrial grade, this must be taken with a grain of salt. True, the Air Monitor has an IP68-rated enclosure, but running two cables (antenna and power) through the same cable gland probably turns the ‘8’ into a ‘3’. Also, the receiver in the shape of a large USB dongle with an open enclosure lacks robustness for tough industrial environments. Yet, I like the SenseLoRa concept, as it really does make things easy at low cost. Also, the fact that it is open source and hackable makes this an attractive system for makers and small businesses.