20 Nov

8×8 RGB LED Grids – the build

Here’s the list of the major items for the build

  • WS2812B RGB LEDs strips
  • Fadecandy module
  • 3mm MDF board (laser cut)
  • Frosted Perspex

Here’s the project outcome.., 8 x 8 LED grids connected up as a 2 down 2 across. All LEDs are illumined with the full brightness test pattern from the Fadecandy server web page. You’ll notice that there is a slight impurity in the ‘white’ because of the different performance of the red green and blue LEDs within the WS2812B. In practice multicoloured patterns are shown so this is not noticeable. Frosted Perspex is used to diffuse the light. A future design may secure the Perspex in a channel within the MDF as no amount of hot glue secured these well enough.

Multiple 8 x 8 grid with a ‘white’ RGB LED signal

This is the rear view showing the LEDs zig zagging across the LED mount panel. The MDF panel is on the shoulders of a narrow piece of MDF around the inside of the frame. LEDs in strips of 50 were purchased so an extra strip had groups of 14 unsoldered to make these up. The 64 were then rolled without twists onto an old ribbon cable spool so that is was easy to unroll flat onto the LED panel. Heavier hook up wire was taken to every 16th LED to cure any dimming of the LEDs at the end of the strip.

64 LEDs zig zag and glued to an MDF board

To make the cubes in to which the LEDs shine 3mm MDF was laser cut into narrow slotted strips, 7 horizontal and 7 vertical. The cube size is about 52mm. MDF ‘staples’ were also cut and within the mount panel you can see 10mm diameter holes for the LED and the staple arms to be accepted. Each LED and staple were hot glued.

Laser cut MDF sections to make cubes

A custom loom was made with heavier gauge (16AWG) hook up wire for the ground and +5V – 64 LEDs take about 2 Amps at full brightness. When soldered onto the pins and the crimp folded over this just fits the JST connector. For mobile use power was taken from a 12V car battery with a 5 Amp DC to DC step down buck converter module adjusted for 5V output. One per 8 x 8 grid and again part of a loom – à la spaghetti junction – manageable with only 4.

Using the Fadecandy module and the Processing.org IDE the project was quite code light.

  • Code to write patterns to the LEDs was just a few lines
  • Libraries for images, video and audio are easily available
  • Processing code and Fadecandy’s fcserver could be a computer that we could leave at an installation (e.g. Raspberry Pi)

Sample Processing.org code for this project is available on Github…

12 Nov

8×8 RGB LED Grids

One of our long running projects was to design and build large form factor RGB LED grids for a Processing day involving algorithmic soundscapes with reactive displays.

Unforteuntaly due to lockdown that didn’t happen, but the development and construction of the grids continued and during a break in lockdown, we did a guerilla art installation displaying ‘8 bit’ style fireworks and fire displays between Halloween and Bonfire night.

This video is the result

08 Jan


A while back hackaday posted about Trammel Husdons Charliewatch (An analog watch that uses 72 tiny ‘charlieplexed‘ leds.

We liked the project so thought we’d have a go at building some, plus it was a good excuse to try our hand at small component (0603) SMT solder paste assembly and pizza oven reflow.

Case printed on an Anycubic Photon in FunToDo Industrial Black.

With a few cosmetic tweaks to the PCB (the original used numbers but Roman Numerals seemed a bit more appropriate for an analog watch) and a bunch of PCBs ordered from JLCPCB, we assembled a couple to test and to design a new case around.

Checking the PCB alignment…
Reflow soldering in a Pizza Oven!
Post reflow.
And a shaky video showing one of the hourly animations.

Future updates will include updates on final case designs and materials.

More details on github

20 Nov

UnitSeven is no more :(

The local maker space ‘UnitSeven’ is now closed.

MakeBmth are still meeting and working on projects.

Join the slack channel, mailing list or drop us an email to find out more about what we are working on.

08 Jun

UnitSeven Maker Space

Thanks to Daizy.io there is now a fledgling Maker Space in Poole and MakeBmth will be meeting there every Thursday and helping fit-out the space and working on projects.

The space needs your help and support, so if this is something you think could be useful for the community, please come along and lend your support!

UnitSeven Maker Space is located at Unit 7 Birch Copse, Technology Road, Poole, BH17 7FH

04 Mar

Coffee Machine Water Filter Monitor

Recently we have been working on a Water Monitor for Coffee Machine filters.

The problem: Coffee Machine water filters stop working after x number of liters of water have been filtered. That varies depending on the hardness of the water which can vary over time. It takes time for an engineer to visit each site and test the water quality and assess the effectiveness of the water filter, so filters may be replaced days or weeks after they are no longer effective or could be replaced prematurely if based on usage estimates.

The solution? Measure the difference between the input and output of the water filter and the volume of water that has passed through the water filter. In addition, we can measure the water temperature to try and calculate the Total Dissolved Solids (TDS). We need the water temperature as it is required in the TDS calculations. Send that data to a backend system for processing and presentation allowing proactive management of all deployed water filters.

We based our prototype solution on off the shelf modules and components. At its heart is an ESP32 devkitc with two DFRobot TDS modules, a (modified) flow meter and a DS18B20 temperature sensor. A custom PCB & 3D printed case.


The firmware waits for data from the flow meter and then records input & output TDS values in turn and sends that data via MQTT over TLS for back-end processing and presentation.

Node-RED example dashboard presenting water quality information.

The firmware presents a password protected hotspot for configuring the device wifi connection credentials & ssl certificates as well as presenting current water quality readings.

22 Apr

Drawing machine (vPiP)

We’ve decided to take a break from the Wireless RGB Pixels project and revisit the hanging v plotter.

We are looking at making the various parts of the system independent services that talk over MQTT. This allows us to change the various bits of the system in a modular fashion.

Starting with the communication between the current Python vPiP scripts and the hardware. This will be a c/c++ binary that subscribes to the MQTT broker and listens for messages that it should pass to the hardware. The existing Python scripts will publish the relevant plotter data to the MQTT broker. This allows us to potentially control many drawing machines at the same time. It should also make the task of adding a GUI or app a bit easier. The GUI or app will publish messages to the machines and subscribe to messages that they can act on.

As a side note, if you have been following this project, you may have seen (or experienced) the glitchy stepper motor problem recently. This was due to the duplication of python processes and has been fixed in the existing version. Get the latest code from github.

08 Jan

Wireless RGB Pixels – Prototype PCB (v1.2)

The prototype PCB for the wireless RGB pixel is at v1.2.

Front of v1.2 PCB pinout (top) and back of PCB showing NRF module (bottom)

This version fixes a mistake I made with the power pins (I misread the data sheet) and does away with the RC pin multiplexing simplfying and standardizing the SPI comms with the NRF24L01. This also means there is no serial debug output from the ATtiny.

Initial radio range tests with the test firmware are disappointing. Comms was spotty and random. I experimented with the various power levels and have tried removing some of the PCB material and re-orienting the NRF module at an angle to see if that made any difference but it didn’t appear to.

Cropped PCB material near NRF PCB antenna on left, NRF soldered at an angle on back of PCB on right.

Cheap amplified NRF modules from ebay actually reduced the range compared to a standard PCB antenna version.

It will be interesting to compare the non Arduino-IDE based firmware with the test code in terms of radio range and comms reliability. I will update when available.

26 Aug

Wireless RGB Pixels

Taking a break from the hanging v-plotter we decided to work on a project that has been discussed for a long while now… The RGB Wireless Pixel.

The idea is these are self contained full colour lights that can be placed anywhere within radio range and controlled from a master. That is, we command the lights all together or individually to change colour or brightness. With that we can create a pop-up light show that could potentially be synced to music or react to passers by. It may even be possible to put them into the windows of a large building and create a massive display… all without wires!


Prototype Wireless RGB Pixels.

We currently have a working prototype based on an ATtiny85 microcontroller, an NRF24L01+ radio module that you can find on ebay for ~£1 each, a WS-2811/2812 programmable LED and some extra passive components. The circuit diagram is available on github and there are more details on our wiki.

We are calling this version 1. The idea is to get people to design their own version of the hardware for this and get PCBs (Printed Circuit Boards) manufactured. To that end we have been running kicad tutorials (kicad is an open source PCB design program) which can be supplemented with the excellent ‘Getting to Blinky‘ youtube tutorials by ‘Contextual Electronics’. Check out our meetups page for details of what we will be doing at future meetings.

Wireless RGB Pixel_ping_pong_smt

Example Wireless RGB Pixel PCB deisgn with KiCad to fit inside a ping pong ball.

When everyones PCBs are deisgned and manufactured we will then assemble, program and test them and eventually, design enclosures and at some point, if everything works, put on a few light shows somewhere!

Right now the software for v1 is pretty basic and more or less a proof of concept. I hope the software will improve as people build their own Wireless RGB Pixels and start programming them! The PoC code is also on github.

Future plans for the project  are already being discussed for v2 which will allow the use of sensors in each Wireless RGB Pixel as well as an upgraded micro-controller to allow for these and other features.