Tindie is a great place to find uncommon electronic components or weird/interesting boards. I use to stroll around it’s products to basically see what’s new. It’s like Kickstarted but for real. One such uncommon and new electronic components is the Panasonic’s Grid_EYE AMG88 [datasheet, pdf] infrared sensor. And I first learn about it through Peasky Products breakout board at Tindie.
And if you have been reading me lately you might know I’m going through my own LED fever. My latests “sliced” projects are not the only ones I’m working on at the moment. So it was not surprise my brain immediately linked an 8×8 IR array with an 8×8 LED matrix display. You see?
So what do you have if you throw in a box an IR sensor and a LED matrix, add a small microcontroller, a LiIon battery and a charger and a step-up to power the LEDs? Well, in my case the outcome has been a bulky but nice camera (albeit a very poor resolution one).
I know there are commercially available IR Cameras like this one [Ebay]. They have 300k pixels and can overlay a normal image over the IR image and other fancy stuff, but they are also more expensive (around 200€ the best deal) and waaaaaay less fun to build.
I’m working on a project were I have to build a network of battery powered sensors over a territory the size of a small town.The sensors will monitor power consumption, temperature and humidity in energy poor households. Often the families in that situation can’t afford an internet connection at home so WiFi is out of question. GPRS would be an option but lately other radio technologies have come to my interest.
I’m a core member of The Things Network Community in Catalunya. LoRa is one such technologies. The (soon) availability of affordable gateways and the open nature of the software stack (from gateway firmware to backends to handlers) make it a great candidate to build an open, libre wireless sensor network that can cover large territories with few gateways.
Someday soon I’ll talk about the gateways, backends and so. Now I’m focusing on nodes. The idea is very similar to my previous post about a Moteino energy monitor node with an RFM69 radio, but using a LoRa radio and LoRaWan protocol instead. There are several options here. The cheaper and more common is to use a HopeRF RFM9X LoRa module and implement the LoRaWan specification in code. There are already libraries for arduino and alike that implement the LoraMAC specification almost at 100%. But for my first try I used another approach.
Microchip is selling a serial module that implements the full LoRaWan stack and communicates with your favourite uC through serial. The Microchip RN2483 (in the EU) is very easy to use and it’s price is not very different from HopeRF modules (both are about 15 euros at DigiKey). It’s the same module that the people at The Things Network have used for their The Things Uno prototyping platform (and Arduino Uno with a RN2483 module).
Question is: is the RN2483 a good choice for a battery powered LoRaWan node?
Some 3 years ago I started building my own wireless sensor network at home. The technology I used at the moment has proven to be the right choice, mostly because it is flexible and modular.
MQTT is the keystone of the network. The publisher-subscriber pattern gives the flexibility to work on small, replaceable, simple components that can be attached or detached from the network at any moment. Over this time is has gone through some changes, like switching from a series of python daemons to Node-RED to manage persistence, notifications and reporting to several “cloud” services.
But MQTT talks TCP, which means you need some kind of translators for other “languages”. The picture below is from one of my firsts posts about my Home Monitoring System, and it shows some components I had working at the time.
All those gears in the image are those translators, sometimes called drivers, sometimes bridges, sometimes gateways. Most of them have been replaced by Node-RED nodes. But not all of them. This is the story of one of those gateways.