I have made my new cortex M0 based microcontroller board operational with FreeRTOS.
The chip is a W7500P
- a cortex M0 with 16KB SRAM and 128KB Flash
- hardware tcp/ip stack incl mac/phy on board (P101G)
This chip is a single chip microcontroller/ethernet/internet IoT solution, no software TCP/IP stack that can fail or hacked. For TCP/IP buffers it has another 32KB SRAM, this can be used by 8 simultaneous TCP connections (sockets open at same time).
I like this chip because it eliminates a lot of other stuff on the board. It is fast, and has lots of IO.
I added a SD-card connector for data-logging applications.
My main application will be small measurement and control applications, adding network easily and securely, super fast bootup times (0.1 sec instead of 20 sec, no linux based board with large bodies of software)
Yesterday and some days before I did some experiments in testing the LoRa radio modules I have from microchip.
The modules were connected to some laptops over USB serial.
I wrote some python scripts to send data using the pyserial library.
One laptop was sitting on a table indoors, no real antenna, just a piece of wire.
The other laptop was outdoors, walking around, no real antenna, just a piece of wire.
The spreading factor for LoRa was SF12, power was set to high.
Further details available on request. (email me)
This experiment was very successful, about 1 kilometer, good connection, no loss of data.
In the picture above, Richard is holding the laptop and the RF module, we are about a kilometer away from TX and get perfect data, on the overpass above the A2 road.
But when we got between a lot of buildings, the results were not that good. At 700 meter we lost connection. 500 meter was mostly fine.
In Tilburg an experiment was done.. and 500 meter urban was not a problem.
Today the first LoRa modules arrived.
I will be hooking these things up to a new board I am working on, it also contains a W7500P from wiznet (a cortex m0 with ethernet/IP/TCP stack inside)
I Chose the complete LoRaWan implementation module from microchip to get started quickly. It communicates using a serial port using readable ASCII commands to the controlling MCU.
Next step is making a break out board for this thing, it looks big but is only about 26.7 mm long and 3.3 mm thick.
I will keep you updated.
What is its use? It can communicate over RF (868 MHz) using LoRa protocol, using very little energy and over a very long range (10 km??)
I am working on a easy to install sound-level and energy-monitoring/control system and think these modules can solve a piece of my very complex puzzle.
It appears everyone in the world is jumping on the bandwagon right now to enable this IoT stuff, but real results and implementations are hard to find.