Tines WiFi button meets TP-Link Kasa Smart Plug

I've been using Tines more in $dayjob and for tinkering with some personal projects; so when Tines reached asking if I wanted to have a play with a new device they were experimenting, I was intrigued to learn more!

What arrived was a nifty ESP32, RGB LED shield and touch sensor all housed in a plastic case with a translucent 3d printed top rocking the Tines logo. Plugging in the USB port fired up an AP that could be connected to to configure the Wireless settings, and define a Tines webhook URL. There's also a capacitive button on top which acts as a button and triggers a webhook, as well as lights up the LEDs in the Tines purple. So we have a physical button that can initiate any Tines story we want. What could we use this for?

TP-Link Kasa Smart Plug

I have a few TP-Link Kasa Smart Plugs around the house for remotely controlling random things including my 3d printer: it's a safety feature should I ever need to cut the power if anything were to happen mid print. Maybe we could hook the button up to that? (Octoprint - a dedicated 3D printer controller - actually has a plugin for this already)

I initially completely overlooked the below referenced Cloud libraries, and instead found myself patching together various posts on the Cloud API.

A Python library to remotely control TP-Link smart home devices using their cloud service - no need to be on the same network as your devices

Using this, I was able to review the Python library and build out a story.

Step 1. Login to TP-Link Cloud

Logging in is pretty trivial, we send a POST request to https://wap.tplinkcloud.com with a JSON payload. Specifically, it must contain our TP-Link Username (we can store as a Tines Resource), our TP-Link Password (we can store as a Tines credential) and we have to provide a UUID (we can use the STORY_RUN_GUID() function).

If this is successful we'll receive a token we can use for subsequent requests.

Step 2. Get Device Status

Next up we can get the device status. Firstly we need to know the DeviceId, so a POST request to https://wap.tplinkcloud.com?token=<TOKEN> with a JSON payload of {"method": "getDeviceList"} returns a list of devices including the type, friendly name and assorted IDs.

With the deviceId of the plug in question, we can then get the status. This again requires a POST request to https://wap.tplinkcloud.com?token=<TOKEN>, with a JSON payload containing the passthrough method, and params of deviceId and some requestData.

The equivalent curl:

curl --request POST "https://eu-wap.tplinkcloud.com/?token=YOUR_TOKEN_HERE HTTP/1.1" \
  --data '{"method":"passthrough", "params": {"deviceId": "YOUR_DEVICEID_HERE", "requestData": "{\"system\":{\"set_relay_state\":{\"state\":1}}}" }}' \
  --header "Content-Type: application/json"

The request data is escaped, and the API expects it in this format, so you'll need to do some jiggery-pokery to get the format right; we can achieve this with the JSON() formula.

The response will be a nested JSON payload inside the JSON response; you can use JSON_PARSE() to parse this out.

3. Flipping the plug relay_state

Included in the response will be the relay_state which determines if the plug is currently on or not. We can simply then flip the state.

A simple trigger provides an if/else statement depending on the state.

To change the state, we need to send another POST request to the TP-Link Cloud with another JSON requestData payload: {"system":{"set_relay_state":{"state":0}}}. 0=off, 1=on.

And with that, a tap of the Tines button will call our Tines story, hit the TP-Link Cloud API and switch on/off our Kasa Smart Plug.