Hi all,
I’m a relative newbie to all this hardware hacking fun, but I’m loving it. I generally use RPi devices of various flavours, but I’m thinking of a project in which that is likely to be overkill.
Basically, I want a temperature and humidity sensor set up in my timber store. I have an Adafruit sensor (HTU21D-F) and an OLED display, both of which I’m currently driving from my Pi Zero W. That allows me to also upload data to ThingSpeak for remote reference.
What I’d like to know is, is there an alternate platform that will allow me to sense the environment, display it locally and upload the data but that isn’t Pi-based? Ideally I’d like to remove the need for a full OS boot. Is something Arduino-esque a possibility, or is the hardware cost going to be silly for the processor and wifi capability?
There are dozens, if not hundreds, of choices out there, but they all offer a different set of trade-offs. How experienced are you as a programmer? The Pi has the benefit of (aside from being pretty cheap in the case of the Zero W) being really easy to program and debug.
Alternatives, such as the myriad Arduino platforms and ESP8266, can be a little trickier to get up and running.
Any reason why you want to avoid the full OS boot? You can certainly harden the Pi against SD card faults, and in my always-on Pi projects and the ones we have in the office we’ve not seen a failure for years.
It’s more for convenience, really. I am building a couple of these units, one of which will be going to my friend’s guitar building business where this info is pretty critical to his storage areas. I was hoping to make it as simple as possible to send him the unit and get it up and running. Explaining “you might have to wait for it to boot before you see anything” isn’t a great intro for a non technical person.
I guess if I went down other routes, there’d be issues with setting up the networking properly given I don’t know in advance the network details. Maybe sticking with the low-cost Pi is best, although I am already at my “how many Pi Zero Ws can I buy” limit - i.e. 1. ;)
I’d be interested in your hardening solutions, though. Are they documented anywhere?
Arduinos are cheap, boot instantly and are extremely low power consumption. Adding a way to transfer data from the point of reading to the point of monitoring, over the air preferably, has traditionally been onerous however.
At this point, microcontrollers such as the ESP8266 are arguably the best cost/feature solution, though I am not keeping track of the gazillion micro released on a daily basis, there are definitely alternative such as the Particle Photon board, Omega and Bluetooth capable AVR-based boards such as the Bluno Beetle, to name just a few I know about.
All that to say - yes, there’s a bunch of development boards out there that you might want to look at… recommending one in particular would be hard however, it depends on many factors including cost, i/o, range, your proficiency hacking together the software side of things, etc etc etc.
reading your follow up post, a point-to-point bluetooth data transfer might be your best bet, if networking in your friend’s premises is a concern.
I wouldn’t say putting this together would be for the faint of heart, but it has the advantage - bluetooth range limitation notwithstanding - to be a setup you can test and move about without having to worry about router position in your final location.
On the software side, I’m pretty sure I can cope. I don’t know C, but I am a dev by trade so the skills should be transferable. With a learning curve, of course.
I’m going to look into the solution Volumio seem to use - exposing a soft AP for initial config of network parameters, that is a lot less hassle than having them place a wpa_supplicant.conf in the root of the SD (which I believe is an option in Jessie)