Chronodecahedron

https://esphome.io/ powered physical time-tracking dodecahedron.

Licensing

AGPL-3.0 or later applies to the code and configuration configuration.yaml
CC-BY-NC-4.0 applies to the 3D-model, description and other support material

Project is WIP, but close to completion

Documentation is lacking at some points, but this is personally not a high priority. The design is mostly settled, but might get some minor touchups. Software might need some improvements, especially for keeping a usage history on the ESP. Right now, this needs to be done manually.

What is this?

This device is a physical time-tracking device to easily track how long you work on what.

It consists of a 3d-printed dodecahedron (12 sided platonic solid) and uses an accelerometer to detect which side faces up.

By using esphome as a platform, it is then able to expose the detected side as a sensor over MQTT or other protocols.

Check out the model on a360.co. The STL and f3z are available in this repo.

Use-Cases

Tracking time for projects (E.g. freelancers that switch between projects)
Use as scene-selector in home automation setups

Feel free to open PRs to extend this list :)

What do I need?

Tools

Soldering Iron
Desoldering tools
- Pump, wick or whatever you are able to use
3D Printer

Parts

Name	Pcs	Note
Prints
Printed `hull.stl`	1	Use your preferred color+material
Printed `base.stl`	1
Mechanical
M3 threaded inserts	2	Optional, depending on tolerances
M3x8 screws	2	Can be shorter
M2 threaded inserts	2	Recommended
M2x8 screws	2
Double-sided tape
Electrical
Lolin32 Lite	1
GY-521 (MPU-6050 Accelerometer)	1
Resistor 200kΩ THT	2	Other large sizes fine, too(50kΩ-500kΩ)
Li-Ion battery (with protection)	1
Jumper wire		`GND`/`INT` conection
6x2.54mm pin header	1	Direct connection of the GY-521
Solder

Assembly

0) Sourcing

Source the parts on your own
Print the parts with whatever material you prefer

1) Threaded Inserts

Melt the two M3 inserts into the holes of the printed hull.stl
Melt the two M2 inserts into the two blind holes of the printed base.stl

2) Electronics

(Optional: Desolder the JST-PH header for the battery)
Desolder the LED on the GY-521 (white component next to the x-axis silkscreen)

Before	After

Stick both resistors with one lead through GPIO33 and make a solder connection
Solder the other lead of one of the 100kΩ resistors to the +-pad of the battery connector
Stick the other lead of the second resistor through GND, but don't connect it yet

Put a piece of jumper wire (~6cm) through GND, now solder both the resistor and wire to GND
Solder another short piece of jumper wire (~2cm) on INTof the GY-521
Break away one of the pins of the pin header (you will have one single pin and a row of 5)
Solder the single pin on VCC of the GY-521, the remaining row on the pins SCL to ADO

Solder the other end of the long jumper wire to GND of the GY-521 (shown here without Board on the other side)

Solder the GY-521 into 3V to GPIO17 of the Lolin32 Lite (This will leave GPIO22 and GPIO16 unconnected)
- Make sure that it's relatively parallel to the Lolin32 Lite
Solder the other end of the short jumper wire to GPIO13 of the Lolin32 Lite
Cut the pins on the back of the lolin32 flush

(If you removed the JST-PH jack: Solder the battery to the pads))

3) Firmware

Modify the yml-files in the esphome directory to your needs (especially secrets.yml)
Connect the Lolin32
Run esphome run chrono.yml in that directory
Check that it works as expected (Side detection, battery level, battery charging)
- The battery level might require fine-tuning. Measure the actual battery voltage level and compare it to the raw reported one.

4) Assembly

Use the M2 screws to attach the Lolin32 to the base.stl

Use the double-sided tape to attach the Li-Ion battery to the inside of the hull.stl

Close the base.stl and the hull.stl and connect them with the M3 screws.

`chronodecahedron-watcher`

./src contains a small python script that connects to MQTT and dumps the state of the cube in a csv-like fashion (separator is - space), for easier processing in spreadsheets.

It can also be configured as a service on NixOS devices by:

Adding this repository as a flake input, e.g.:

    chronodecahedron = {
      url = "github:CRTified/Chronodecahedron";
	  # We only use basic library functions and packages, following your nixpkgs should be safe:
      inputs.nixpkgs.follows = "nixpkgs"; 
    };

Importing chronodecahedron.nixosModule as a module
Configuring the service under services.chronodecahedron-watcher, e.g.:

  services.chronodecahedron-watcher = {
    # Make it depend on mosquitto
    enable = config.services.mosquitto.enable;
    user = "chronos";
    group = "chronos";
	
    mqttServer = "localhost";
    mqttPort = 1883;
	
    mqttCredentialsFile = "/var/keys/mqttAuth";

    device = "timecube";
    logFile = "/root/chronodecahedron.csv";
  };

Note that credentials bypass the nix store and are stored in /var/keys/mqttAuth. This file needs the following entries adapted to your need:

CHRONO_MQTT_USER=$mqttuser
CHRONO_MQTT_PASS=$mqttpass