Cheap boards like the ESP-12F (ESP8266) allow you to remotely control a device or receive sensor data, like that from a DHT11 temperature-humidity sensor. Instead of paying a lot of money, you can flash your own firmware on a device and make your own custom IoT device.
MQTT is a messaging protocol used to communicate with the device. You can use something like Mosquitto to communicate with your new IoT device. It is lightweight protocol and easy to work with.
You'd use something like an ESP32 – which has Bluetooth – if you want a simple BLE beacon, otherwise if you don't need Bluetooth then an ESP8266 device would likely work better.; If you want to look at related videos, I'd suggest looking at the YouTube channel Andreas Spiess publishes with various devices. He has a few videos on BLE and ESP32 (ex: https://www.youtube.com/watch?v=KNoFdKgvskU) where he goes into detail.
On the one side, you have WiFi and therefore can communicate with servers using different protocols. On the other side, you have spi, i2c and gpio, to talk to sensors, blink LEDs, move motors.
The ESP8266 is wifi. The slightly more expensive ESP32 adds Bluetooth and some extra features. You can use them to run mini web server, MQTT, etc. Think of them like a supercharged Arduino with connectivity built in.
Ahh - so coupled with whatever sensor you have, you can have a wifi broadcast capability at extreme low cost...
So, ostensibly - if you have these all participate in an SSID of e.g. "sensors", then you can place these all over and have a low-cost mechanism to deliver the reads to your (already) existing wifi infra...
So the key, then, is the family of sensor types you want to place on them. The limitations in the case of this object are power and size....
So given that - whats the minimum size battery req'd to run this little guy?
Then What is the power req of the sensors you attach -- then whats the lifespan of that power budget and then servicability to replace it?
I like this... a lot.
I have a bunch of BLE sensor beacons from china which cost ~8 but they are dumb as rocks.
This provides a heck of a lot more functionality than those...
The esp8266 module itself runs at 3.3V but seems happy with a couple of AA batteries. Tried with CR3032 but it can't deliver enough current. After all, it is doing WiFi.
MQTT is a messaging protocol used to communicate with the device. You can use something like Mosquitto to communicate with your new IoT device. It is lightweight protocol and easy to work with.
You'd use something like an ESP32 – which has Bluetooth – if you want a simple BLE beacon, otherwise if you don't need Bluetooth then an ESP8266 device would likely work better.; If you want to look at related videos, I'd suggest looking at the YouTube channel Andreas Spiess publishes with various devices. He has a few videos on BLE and ESP32 (ex: https://www.youtube.com/watch?v=KNoFdKgvskU) where he goes into detail.