Patrick
This is a digital download item only. Nothing will be sent in the post. You can follow the tutorial below to get it working for free using this free version of the code here, which measures and logs temperatures limited to 20-24 Degrees Celsius: https://odonodesign.com/blog/wp-content/uploads/2026/06/Free_version_transmit.hex_.zip
To see the build tutorial, see below or for a better experience, see it here:
Once you are satisfied with the project, you can download the full premium code by scrolling down to purchase the premium version on etsy, which will allow you to measure and log between 0-99 Celsius. You will be able to download the full code straight away.
📡 Overview
In this project, we build a long-range wireless temperature monitoring system using LoRa radio communication (10km range), a PIC microcontroller, and a NodeMCU ESP8266. See the demo of it working here.
The system allows you to monitor temperature from remote locations such as a garden, shed, greenhouse, or outdoor enclosure afar ( up to 10km away) — and view live data anywhere in the world using the ThingSpeak wifi cloud platform.
Unlike typical WiFi-based sensors, this system does not require WiFi credentials to be stored on the outdoor sensor device, making it significantly more secure (no need to store wifi username and passwords directly on the ESP8266 which can be accessed by anybody outside) and much higher range to remotely monitor areas up to 10km away from your wifi router at your home/office. Due to the Lora transmitter, you are no longer locked to keeping the temperature sensor 10 metres in proximity to your wifi router (like the inferior Tapo system), as this system doesn't rely on wifi to transmit the temperature data. Using Lora opens for this part of the interface opens up a whole load of new possibilities.
How to build this yourself?
If you want to skip the blurb on what this does and how it does it, please scroll down to the build section to get to the nitty gritty part of how to build this yourself DIY style! All the components will be a total maximum of £20 depending on the AliExpress market prices. A Full BOM list and purchase links are also included in the tutorial below. This is extremely cheap considering professional market temperature loggers are priced upwards of £200!
The How
🧠 System Architecture
The project is split into two main parts:
[ Sensor Node (Outdoor) ]
PIC16F628 → DS18B20 Temperature Sensor → LoRa Transmitter
↓
Wireless Long-Range Link (LoRa)
↓
[ Base Station (Indoor) ]
LoRa Receiver → NodeMCU ESP8266 → ThingSpeak Cloud
🌍 How It Works
1. Sensor Node (Outdoor Unit)
The outdoor unit is built around a PIC16F628 microcontroller connected to a DS18B20 temperature sensor.
The PIC reads temperature data and formats it ready for transmission.
I.e: 24 = temperature value (°C)
This data is transmitted via LoRa every 5 minutes, then both the pic microcontroller and lora go to sleep before the next transmission, thus conserving battery power.
2. Receiver Node (Indoor Unit)
The base station uses a NodeMCU ESP8266 connected to a LoRa receiver module. This is powered using a usb cable and left on indefinitely.
It:
Receives incoming LoRa packets
Extracts the temperature value
Validates and processes the data
Once decoded, the value is passed to the WiFi stage.
3. Cloud Upload (ThingSpeak IoT)
The NodeMCU uploads the processed temperature value to ThingSpeak, allowing:
Real-time graphs
Historical data logging
Remote access from any device with internet
No custom app is required — just open your ThingSpeak channel in a browser on you phone, desktop or smart tablet (i.e iPad).
📊 ThingSpeak Dashboard
ThingSpeak provides:
Live updating temperature graph
Automatic data logging
Mobile and desktop access
Long-term data storage (ideal...
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