# Building a Julia-Powered E-Ink Dashboard: A Dev Log

**URL:** <https://discourse.julialang.org/t/building-a-julia-powered-e-ink-dashboard-a-dev-log/130709>\
**Category:** General Usage\
**Tags:** development, raspberry-pi, project, maker\
**Created:** [July 14, 2025, 4:28pm UTC](https://discourse.julialang.org/t/building-a-julia-powered-e-ink-dashboard-a-dev-log/130709 "2025-07-14T16:28:08Z")\
**Posts on this page:** 1\
**Showing post:** 3

<div class="post-metadata">

**Author:** ![TheCedarPrince](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/thecedarprince/32/17323_2.png) [@TheCedarPrince](https://discourse.julialang.org/u/TheCedarPrince)\
**Post date:** [July 14, 2025, 5:25pm UTC](https://discourse.julialang.org/t/building-a-julia-powered-e-ink-dashboard-a-dev-log/130709/3 "2025-07-14T17:25:40Z")

</div>

**Log 02: July 13th, 2025 - Weather Imagineering**

After tinkering further with OpenMeteo, I decided to take a break and determine what data I want exactly. I concluded that basically, this is the information I want from the Weather Forecast API:

**Location**

- `latitude=42.3751`
- `longitude=-71.1056`

**Daily Variables Requested**

- `temperature_2m_max`: Daily maximum temperature at 2 meters
- `temperature_2m_min`: Daily minimum temperature at 2 meters
- `sunset`: Time of sunset
- `sunrise`: Time of sunrise
- `wind_speed_10m_max`: Maximum wind speed at 10 meters
- `wind_gusts_10m_max`: Maximum wind gusts at 10 meters
- `wind_speed_10m_min`: Minimum wind speed at 10 meters
- `wind_gusts_10m_min`: Minimum wind gusts at 10 meters

**Hourly Variables Requested**

- `temperature_2m`: Temperature at 2 meters
- `uv_index`: UV index
- `precipitation_probability`: Probability of precipitation
- `precipitation`: Amount of precipitation
- `relative_humidity_2m`: Relative humidity at 2 meters
- `wind_speed_10m`: Wind speed at 10 meters
- `wind_direction_10m`: Wind direction at 10 meters

**Other Options**

- `timezone=America/New_York`: Output times in the Eastern Time zone (encoded as `%2F`)
- `forecast_days=3`: Request a 3-day forecast
- `timeformat=unixtime`: Timestamps in Unix time format (seconds since epoch)
- `wind_speed_unit=mph`: Wind speeds in miles per hour
- `temperature_unit=fahrenheit`: Temperatures in Fahrenheit
- `precipitation_unit=inch`: Precipitation in inches

**Curl Request Example:**

```sh
curl https://api.open-meteo.com/v1/forecast?latitude=42.3751&longitude=-71.1056&daily=temperature_2m_max,temperature_2m_min,sunset,sunrise,wind_speed_10m_max,wind_gusts_10m_max,wind_speed_10m_min,wind_gusts_10m_min&hourly=temperature_2m,uv_index,precipitation_probability,precipitation,relative_humidity_2m,wind_speed_10m,wind_direction_10m&timezone=America%2FNew_York&forecast_days=3&timeformat=unixtime&wind_speed_unit=mph&temperature_unit=fahrenheit&precipitation_unit=inch

```

And Air Quality API:

**Hourly Variables Requested**

- `us_aqi`: U.S. Air Quality Index (based on EPA standards)

**Other Options**

- `forecast_days=3`: Request a 3-day forecast

**Curl Request Example:**

```sh
curl https://air-quality-api.open-meteo.com/v1/air-quality?latitude=52.52&longitude=13.41&hourly=us_aqi&forecast_days=3

```

* * *

From there, I began tinkering with how to display this data on my display. I sketched out a small draft of this here:

 ![image](https://global.discourse-cdn.com/julialang/original/3X/f/0/f01ade85834028ccb078834b0a202c21c68ddaec.jpeg)

Basically, I am imagining using Makie.jl and a PolarAxis radial chart to display this information (thanks to @asinghvi17 and @sdanisch for the tips here):

> You can make multiple polar axes and use [PolarAxis | Makie](https://docs.makie.org/dev/reference/blocks/polaraxis#Radial-Offset)

In my designing, I found this [example to be beautiful](https://observablehq.com/@analyzer2004/west-coast-weather-from-seattle-to-san-diego) and something I could base my work off of:

 ![image](https://global.discourse-cdn.com/julialang/original/3X/c/3/c389876ddf3e13e295e4d03fbc87a1bc183dccad.jpeg)

I also found [this other example](https://www.informationisbeautifulawards.com/showcase/4231-does-size-matter) which was also hugely inspiring:

 ![image](https://global.discourse-cdn.com/julialang/original/3X/5/b/5b7a8e6dd25c9e3879fd0d08123dfd8215f3ac8f.jpeg)

This will be a task for future TCP.

* * *

Finally, I decided to put some thoughts to code and began drafting a Jinkies.jl framework for how to “chunk” the regions of an e-ink display. As of now, I have two structs called `Display` and another called `Component`. `Display` holds information about the e-ink display and what components are in the display. A `Component` holds plotting information about what goes into the display and where.

I am imagining making `Component`’s more like an interface too so I can make any component that could be rendered to an image using tools like Makie, Luxor, and more.

Currently, I have made a PrettyTables.jl interface to represent an e-ink display’s pixels in a coarser granularity than pixel dimensions. Here’s how things look so far:

```julia-repl
julia> Jinkies.set_display_grid!(100, 120)

E-Ink Display Grid
┌─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┐
│ │ 001 │ 002 │ 003 │ 004 │ 005 │ 006 │ 007 │ 008 │
├─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┤
│ 1 │ ⬤ │ ⬤ │ ⬤ │ ⬤ │ ⬤ │ ⬤ │ ⬤ │ ⬤ │
├─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┤
│ 2 │ ⬤ │ ⬤ │ ⬤ │ ⬤ │ ⬤ │ ⬤ │ ⬤ │ ⬤ │
├─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┤
│ 3 │ ⬤ │ ⬤ │ ⬤ │ ⬤ │ ⬤ │ ⬤ │ ⬤ │ ⬤ │
├─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┤
│ 4 │ ⬤ │ ⬤ │ ⬤ │ ⬤ │ ⬤ │ ⬤ │ ⬤ │ ⬤ │
└─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┘

```

And then for colors, I can do something like this to say where a part of an e-ink display already has a component:

```julia-repl
julia> Jinkies._update_display_grid_colors!(
    [[1,1], [1,2],[2,1],[2,2]]
)

```

 ![image](https://global.discourse-cdn.com/julialang/original/3X/f/1/f1ec59643354a4c73325b40f8b3ce870cc8be5d3.png)

I like the display representation so far, but I need to mess around a bit further with the component and display interplay. Also encoding what information should be stored here and there.

* * *

And that is where we shall leave the dev log for now. Nice day of exploring, hacking, and imagineering! Onwards!

---

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