Introduction to the Coin Cell Challenge
The Home smart mesh framework has been updated to
- STM32 Nodes using nRF24L01+ for Gateways and Repeaters based on mbed-os
- nRF51822 buttons communicating within the same mesh network (radio and protocol compatible).
- The Mesh protocol has been improved (controlled time to live from user, streaming, simpler IDs)
But one thing was kept unbeatable from cost and efficiency :
=> The Cell Coin STM8L Tag
- BME280 : Temperature Pressure Humidity
- MX44009 : Light
- MRMS211H : Magnet sensors
- Usage of modules very simple to solder, can reduce the cost vs on the shelf tags by soldering only the required module
- cost-less debugger and IDE
- power measures : to be provided during next week (beginning December)
Fully open source available on github
- STM32 Gateway, bridge and Raspberry pi server interface to MQTT on github
- The latest STM8L Coin Cell SW on github
Let's talk about costs for the whole Coin Cell Tag Development Environment
- STM8L + PCB (x10 / 10) + nRF24L01+ : ~ $4 if you're unlucky
- STLink-v2 debugger : ~ $2 you being generous with the seller
- Professional IDE with breakpoints stepping without restrictions (for the full flash size which is already 8 KB covered completely by the demo) => FREE !
Simplicity Vs Complexity
- With Bluetooth, you need a bigger SW stack (hundreds of kilobytes, while it is few kilobytes here 2~ 3 KB)
- With Bluetooth, you need a more expensive uC or SoC
- With Bluetooth, you cannot customize the protocol to your needs
- With a custom protocol you can have a simple mesh starting from few functions, easy to understand and optimize by yourself
- With a custom protocol you can have a huge amount of sensors, using a specific configuration.
- For simple sensors that do not control anything, no door opening, no light switching, security is not relevant as these sensors are beacon like and do not provide more information than what a neighbor could see out of your window.
- The internet security is handled by the raspberry pi that is beyond the custom RF gateway, so you can access your data safely from all over the world, for example I am using a vpn router, so the security is even beyond the rapsberry pi server's hacking.
Mesh 2.0 Protocol
Introduction moved to the end
Impressions and Inspirations moved to the end
Also moved to the end of section. for those really curious how all this started.
Links to project Logs
The Logs consist of specific use cases based on this IoT_Framework going into some details of firmware and software :
- Open the bathroom window, Close the bathroom window : A useful use case to help know when to open the bathroom window depending on the humidity level.
- nrf24l01 Flood Mesh Protocol : The mesh concept on how do the nodes communicate with each other, including the protocol bits details.
- Completely Hackable IoT dashboard : The web technology behind the dashboard that allows you to hack the GUI while the access itself is highly secured. A good example on how you can own your IoT devices, private local network, no third parties, not even for remote access!!!
- Hello Mesh - RGB Colors Broadcast : Although the show goes over the broadcast, the focus is how the STM8 managed to control the WS2812B in assembler.
- 60 RGB LEDs shading with that tiny STM8 : Show details on how colors are shaded before being sent.
- Smart LED Panel - MQTT to x216 WS2812B : out of the box MQTT control of RGB Panel color with a smartphone app.
IoT Framework, what do we have here ?
Below we see both boards contributed by this project the STM8L_RF_Sensors Node, and the STM8S_RF_Dongle that have two use cases, RPi dongle and stand alone repeater. Note that this setup is running field tests now for many months already. The mesh network is a very simple flood concept with a time to live. The rest of the HW is standard from the market, Raspberry...Read more »