Project (2022-03 Plugfest): Retail Demo

[mmccool]

Retail demo using the following devices:

• RGB Light
• Temp sensor
• Door switch

Scenario: get notified via a change in light color when a freezer door is left open or is warm. Using Node-RED integration, discovery, etc.

Note:

1. Will start with simple implementations, then swap in more complicated (e.g. commerical) devices
2. Need to showcase purpose of standards: easy integration, swapping out devices

[mmccool]

So, as it happens, the Shelly Door/Window 2 is ALSO a temperature sensor, but it can only go down to -10C. One interesting point this raises though is how I can reference individual interactions of a Thing and swap in as replacements entire new Things. This relates to how we handle Thing components, modularity, etc.

I'm also going to see if I can get one of the industrial temp sensors I found, such as the NCD Temp/Humidity sensor.

Even though they are expensive, they will have a wider temperature range, will be sturdier, will have better security, etc. and would be more appropriate in an actual retail deployment. BTW: ideally freezers would be smart devices with built-in IoT interfaces. I obviously can't buy a freezer but we should look into whether one exists with such an interface. A freezer obviously has a temperature sensor already since it has a thermostat (temperature control system).

[mmccool]

Recently I have been looking as well into ESPHome devices which can support both MQTT and HTTP. I have several of these working now and MAY be able to add an extension to get them to self-describe with WoT TDs. Will demo in testing call.

[mmccool]

For freezers, BTW, after looking into various options for temperature sensing it seems it is not recommended to put the devices directly inside the freezer. The battery life will be severely reduced and condensation may also be a problem. A better option is to use an RTD sensor, which is basically a resistor on the end of a wire. Then the sensor can be placed inside the freezer and the device on the outside. Also the NCD device can have a number of devices that communicate over LPWAN (900MHz radio) to a hub, which can then communicate using a number of protocols, including MQTT.

Anyway, I have ordered an RTD temp sensor and a separate LPWAN-to-MQTT client for testing. There was no HTTP option (the other option was a USB device which would have required programming to convert into HTTP, but I could just do that from MQTT, so...).