First IOT Project - Remote Temp Sensor
I am new to IOT development and I'm looking to build several small battery powered arduino temperature sensor that will transmit via RF or WIFI to my raspberry pi. I'm hoping someone can point me in the direction on my first project.
@Bryan-Smith Just follow the examples in the build section.
First, you'll need a gateway. Since you are looking to go wireless, I would suggest the serial gateway with nRF24L01+ radios.
For the temp sensors, the Dallas DS18B20 modules are really easy to wire up. Just follow the build example here.
As for them being battery powered, I cannot speak to how long these would last on batteries, but others can pipe in on that. The max current draw according to the datasheet is 1.5 mA with a typical draw of 1 mA. Typical standby current is 750 nA, so I would figure they would last quite a while if you used sleep and limited the time between temperature reads.
I think the best is you get familiar with MySensors first, and you can follow @dbemowsk suggestions for that, to make breakboard versions of sensors and learn the basics with NRF24 radios.
For battery powered sensors the best is to keep using radio modules (and not wifi, way too power hungry), i2c sensors for temperature/humidity like si7021/htu21/bme280 (they can run at much lower voltage and use way less current than DS18, DH11/22 etc) and to use PCBs available on openhardware.io to avoid all the wires and have something more compact. It will require the use of a soldering iron, but a decent one is not expensive and if you're never done it before, learning to solder is pretty easy.
For PCBs you can have a look at EasyPCB which is very convenient to start experimenting when you are fed up with the wires. Lot of people including myself learnt a lot using it, and you will easily get some help if you have a problem using it:
Else for more compact sensors I made NModule and a bunch of shields for building many sensors but it's still a bit fresh and missing examples + a bit harder to solder because of the SMD version of the NRF24 radio I am using:
But first, start as suggested with breadboard/jumpers version to experiment, here: https://www.mysensors.org/build
Depending on soldering skills, there is also the sensebender platform, where minimal soldering is required