Slack two button traffic light

An ESP8266-based Slack status indicator that can read and write a users status using the Slack API. While the concept of the project was concieved independently, it turns out other folks had the same idea before us! As such, the code is based off of the prior work of some clever and generous people who beat us to the punch.

Motivation

Working in a shared work space has a ton of benefits! However, there are some drawbacks; for example, if someone needs to focus on an important task, it can be difficult for their coworkers to know that they shouldn't start up a conversation. Having a visual indicator of a teammates availability, be it a post-it note on the back of a chair, putting on headphones, or something else, can be a quick and easy way to communicate the message. We thought that using a traffic light was perfect fit, since it's fairly intuitive to know when someone is available, busy, or should not be disturbed.

The traffic light

Here's what the traffic toy light looks like:

It costs about $2 USD and is available on a variety of sites. It has a PCB with an integrated IC which runs off of 3 coin cells (~4.7v); it has 2 button switches, a small speaker, and three white SMD LEDs (3.4v drop). Out of the box, the two buttons activate different modes of music and animations using the three LEDs.

Dimensions

• Height: 13.5 cm(5.31 in)
• Width: 4.2 cm (1.65 in)
• Depth: 4.2 cm (1.65 in)

To open up the traffic light toy, we need to remove 4 small Phillips head screws on the back, which are circled in red in the first image above.

With a few modifications, we can just barely fit a header-less D1 Mini ESP8266 board inside of the main body, and plug a USB cable into it. We will need to remove the small speaker, the battery contacts, and trim away a few plastic bits. It is serendipitous that the holes in plastic case behind the speaker will also serve as ventilation to keep the ESP8266 from getting too hot. We will also cut several traces on the PCB (severing a connection) using a hobby knife. Here’s where we need to cut:

Once we cut the wires and PCB traces, we can remove the speakers and the battery contacts. This is what it will look like after this is done:

Now we can start to wire up the ESP8266 D1 Mini. I began by wiring up the LEDs one by one, soldering directly to the junction between the tinned SMD pad on the PCB and the positive terminal of the LED; I used flux, a lower iron temperature, and minimal solder to avoid melting the LED). I opted to include a ~300 Ohm current-limiting resistor between Gnd on the toy (silkscreen on traffic light PCB says V-) and the Gnd pin on the D1 Mini, which also somewhat reduces the maximum brightness.

The code

This project is setup to use PlatformIO for builds and dependency management. Once you have installed PlatformIO, you can import this GitHub repository as a project. Once imported, you can build the project (download all dependencies & compile the code) with the following command:

platformio run

To upload it to a connected device, run:

platformio run --target upload

Setting up Slack

For this device to be able to access and modify your Slack status, presence, and DnD settings, we need to create a secret key that it can use to prove to the Slack API that it has permission to do so. We can follow a guide adapted from these instructions here:

• Create a new Slack App by clicking here
• Name your app whatever you want, such as "My traffic light app", then set the "Development Slack Workspace" to whichever workspace that you want the traffic light to update your status on
• Look on the lefthand side menu for "OAuth & Permissions"
• Scroll down to the section that says "Scopes", then under "User Token Scopes", click the "Add an OAuth Scope"
• Add the following scopes to have full functionality:

Enpoint	scope
setPresence	users:write
setCustomStatus	users.profile:write
getCurrentStatus	users.profile:read
setDnD	dnd:write
getDnD	dnd:read

• Once you've set these scopes, scroll up to the top of the page and click "Install app to workspace"
• Click "Allow" on the next page
• You will now have an OAuth Access Token up the top of the page, this is referred to as the SLACK_ACCESS_TOKEN in the ArduinoSlack library