I make a post on measuring temperature with different sensors and an objective : watch the impact of designing a correct box for you IoT you want to put in a Car.
When sun is lighting your windshield it is not a surprise to get high temperature, but did you expect to get up to 90°C when the outside temperature is about 35°C ?
The packaging have a big impact on temperature as this post will detail it.
After making LoRaWan test in a city environment, I make some test in a rural environment with the objective of evaluating the capability for being used in connected farming environment.
The result is really like what we have got in a city, eventually better in a way as the antenna position was on altitude. The following map makes with 6kbps communication shows the coverage. You can see that the coverage is really limited on the Eastern direction. This is due to higher mountains this way. Mountain are the main limiting elements and as you can see, even on short distance communication they are blocking any signal.
Read more to access the map.
For a certain IoT design I had to understand how my box design impacts the temperature of the circuit and of my battery. To understand how it works in the real environment, I made a small circuit based on an Arduino Nano to get temperature with 6 different sensors and store it in a flash memory for later use.
This post describes the way to do this multi-temperature sensor platform. Code is under GPL.
NiMh batteries
After writing a post about my experience with LiPo Batteries I’m now proposing a post about NiMh. LiPos are good batteries : not expensive with a good energy density, really easy to manage for charging. For these reason they are used in many electronic designs.
But in some applications they are not enough stable, this is as an example the case for an automotive use where the internal temperature of a car can reach higher temperature than 65°C. This is the limit for LiPos. In my experiences I had some having been destroyed due to warm temperature.
NiMh is not an optimal solution but you can find some batteries capable to support 85°C and resist to +130°C before being destroyed and have a fire risk. Varta V500HT is a good example of battery for a such use.
NiMh is less easy to use than LiPos, this post is detailing my experience.
Microchip RN2483 Lora
Making downlink working correctly with RN2483 on LoRaWan is not a simple a quick thing to do if you do not have all the keys to do it. After spending some time to fix my code for this, here are the tips to consider and not forget !
I was looking for a real LoRaWan experimentation on the field, not only a given open field performance where the result do not match the reality.
For this reason, I installed a Kerlink gateway on a friend’s balcony living on a high part of my city. Then I moved a tracker reporting its GPS position on regular basis and day after day I built a map of the area covered by this antenna.
This post details the results of this expermientation
Once you have found the great idea of the year and you want to start implementing your first prototype it is time to choose the right technology. Some would say you should not choose at this step and implement both at end but in my point of view it looks like and economical mistake to do this way. Prototype is to demonstrate and final product. It can request another technology, for sure. But in my point of view the best is to take the right one at the beginning. For most LoRa and Sigfox are both equivalent or for some others one is over the other one, best depends who you ask. In my point of view, if I consider my 2-3 years sigfox experience and my starting experience on LoRa with 1 year background research on it, there is no magic answer. Context of your idea is the keypoint then you have some technical elements to take into account to finalize your decision.
This post will try to illustrate where each of the technology is the best and give you some decision keypoints.
TFT screen on a raspberryPi
This week I had to play with some TFT screen for RapberryPi for making a prototype for a local company. You can find many TFT screen on Internet but most of them are not coming with a nice fresh documentation for being use and it is kickly a mess to get it start with them. I ordered different one having the same 3.2” size matching my need and got 2 of them for starting tests.
This post details how to use a such screen for displaying a picture on it from a console line.