Fork me on GitHub

Project Notes

#018 FretBoard

FretBoard is a multi-project build status indicator, using a WS2811-based LED Strip to display the status of each project.

Full details of the project are available at



  • parse build status from the net using Ethernet shield
  • driving the LED Array with basic build status indication
  • added LED effects (glow) using timer driver
  • added visual indicator when the build status is refreshed and builds-in-progress
  • the physical build - housing this in a suitable case for display
  • wrap up the doco


The Build Status Web Response

We get build status from a web server that supports a simple HTTP 1.0 CSV response. This is probably a proxy to the actual build server. See the fretboard web repository for an example of a proxy that can handle Circle CI JSON API and CruiseControl XmlStatusReport response formats.

The response looks like this:

$ curl -i -0 --raw

HTTP/1.1 200 OK
Connection: close
Content-Type: text/csv;charset=utf-8
Content-Length: 288
X-Content-Type-Options: nosniff
Server: WEBrick/1.3.1 (Ruby/2.0.0/2014-11-13)
Date: Sun, 01 Feb 2015 09:04:18 GMT
Via: 1.1 vegur


Each line of the CSV response includes three elements:

  • project name
  • build activity (CheckingModifications,Building,Sleeping,Unknown)
  • build status (Success,Unknown,Failure)

A couple of features make this easy to deal with:

  • HTTP 1.0 means the Arduino doesn’t need to deal with chunked-encoding.
  • The CSV format is easy to parse either natively from EthernetClient or with the assistance of a library like TextFinder
  • project build status are provided in alphabetical order, hence the Arduino doesn’t need to worry about ordering of results

Parsing the Web Request

I’m using TextFinder to parse the web response. Note that the GitHub repository version of TextFinder is an enhanced version of the original library available from the Arduino Playground.

Other libraries that could be used are amcewen/HttpClient and interactive-matter/HTTPClient.


The LED strip requires 5V and with all 24 LEDs on, current should max out at 1.44A (0.3W * 24 / 5V).

For testing, I’m powering the LED Array from a 5V 2A adapter and the Arduino from USB.

For the final build, I’ll be powering the Arduino from the same 5V adapter powering the LEDs (direct to the 5V pin on the Arduino). There is lots of advice on how to do this e.g. here

  • along with strong caveats since the 5V pin bypasses the onboard regulator, and it is essential to ensure no other power source is simulatneously provided to the Arduino. However, the 5V adapter I am using is regulated, and under test it has worked fine to power the Arduino and LED array together.


The Breadboard

The Schematic

The Build


Not much to the electronics. Core parts:

  • Arduino Uno
  • Arduino Ethernet shield
  • WS2811-based LED Strip
  • 1000µF capacitor for power supply smoothing
  • 1kΩ resistor for current-limiting the LED data line

And then connectors etc depending on the physical housing.

LED Strip Data

WS2811-based LED Strip ships in a strip of 50 LEDs (cut down to 24 for this project). The basic details:

  • Certification: EMC,FCC,LVD,RoHS
  • Brand Name: olym-led
  • Features: ws2811
  • Model Number: ol-rgb-0.3w
  • Voltage: 5V
  • LED Power: 0.3W
  • Waterproof IP Grade: IP68
  • Led Lifespan: Over 50000 hours
  • Light Color: RGB FULL Color


Project Source on GitHub Project Gallery Return to the LEAP Catalog

This page is a web-friendly rendering of my project notes shared in the LEAP GitHub repository.

LEAP is just my personal collection of projects. Two main themes have emerged in recent years, sometimes combined:

  • electronics - usually involving an Arduino or other microprocessor in one way or another. Some are full-blown projects, while many are trivial breadboard experiments, intended to learn and explore something interesting
  • scale modelling - I caught the bug after deciding to build a Harrier during covid to demonstrate an electronic jet engine simulation. Let the fun begin..
To be honest, I haven't quite figured out if these two interests belong in the same GitHub repo or not. But for now - they are all here!

Projects are often inspired by things found wild on the net, or ideas from the many great electronics and scale modelling podcasts and YouTube channels. Feel free to borrow liberally, and if you spot any issues do let me know (or send a PR!). See the individual projects for credits where due.