HowTo: pxlBlck - build pxlDigit_clock with the pxlDigit PCB

I got the idea for the pxlDigit_PCB while building the pxlDigit (article here: have come.

There, the pxlDigit is constructed from individual WS2812 LED segments. To do this, the LEDs must first be glued into the 3D printed housing and then soldered together in the housing. This step in particular is not so easy due to the lack of space. :/

That's why I have the pxlDigit_PCB designed. The LEDs, the ESP8285 and the rest of the electronics can be installed on it. This allows you to first build, test and program the entire board and then insert it into the 3D printed housing of the pxlDigit or the pxlDigit_clock.

Thanks to the integrated USB-C connection, the pxlDigit can also be supplied with power directly and the firmware can be programmed if necessary.

In addition, the following (optional) components can be installed on the PCB:

  • BME280 Climate Sensor
  • TSL2591 Brightness sensor
  • MPR121 Touch sensor for up to 12 touch electrodes

For the pxlDigit PCB to work properly, it should be installed in the 3D printed housing. In this way, the light from the LEDs is better distributed and the individual digits can be easily combined to form a larger display. For example, you can use the digits to build a follower counter, a score display or even a clock.

Four digits are required to build the clock, which are then mounted on a 3D printed base. This allows the current hours and minutes to be displayed.

Of course, there are other ways to use the pxlDigit_PCB as a display. The pxlDigit_clock shown in the following article is a first example 🙂

The structure of the "pxlBlck_digitClock" clock is described in the following article.

Safety instructions

I know the following notes are always kind of annoying and seem unnecessary. Unfortunately, many people who knew "better" have lost eyes, fingers or other things due to carelessness or injured themselves. Data loss is almost negligible in comparison, but even these can be really annoying. Therefore, please take five minutes to read the safety instructions. Because even the coolest project is not worth injury or other trouble.

Affiliate links/advertising links

The links to online shops listed here are so-called affiliate links. If you click on such an affiliate link and make a purchase via this link, will receive a commission from the relevant online shop or provider. The price does not change for you. If you make your purchases via these links, you support in being able to offer other useful projects in the future. 🙂 


For the assembly you have to master SMD soldering tasks. The following articles contain tips for this.

Required tools:

1xSoldering ironBuy at Amazon
1xUSB soldering ironBuy at Amazon
1xThird handBuy at Amazon
1xSoldering tip cleanerBuy at Amazon
1xHot glue gunBuy at Amazon
1xSLA 3D printerBuy at Amazon
1xM2 internal tapBuy at Amazon
1xM3 internal tapBuy at Amazon
1xM8 internal tapBuy at Amazon
1xM8 external tapBuy at Amazon
1xTorx screwdriverBuy at Amazon

Required material:

1xM2x6 grub screwBuy at Amazon
6xM2x6 countersunk head screwBuy at Amazon
3xM3x6 grub screwBuy at Amazon
1xM3x50 countersunk head screw Buy at Amazon
6xM2 thread insert Buy at Amazon
3xM3 thread insert Buy at Amazon
3xCylinder magnet 5x2mm Buy at Amazon
1xCylinder magnet 10x5mm
1x623 Ball bearing Buy at Amazon
2x608 Ball bearing Buy at Amazon
1xJST SH connection cable Buy at Amazon
1xELEGOO ABS-Like 3D Printer Resin Buy at Amazon
1xKeber Buy at Amazon
1x10x2mm aluminum tube Buy at Amazon
1xSolder Buy at Amazon
1xUSB power supply unit Buy at Amazon
1xUSB-C cable Buy at Amazon

The components required to assemble the pxlDigit PCB can be found in the following file.

If there are more recent versions of the pxlDigit board, you can find the available versions in the Git repository at:

The structure of the pxlDigit board

In the past I often inserted single pictures here to show which components have to be soldered where on the PCB.

An even better way to get an overview of which components belong where on the PCB is shown in the following paragraph. Thanks to the work of OpenScope Project you can now generate very helpful HTML files in which you can directly see which components have to be installed where on the PCB.

You can see the overview for the pxlDigit_PCB here: pxlDigit_PCB

The current file can also be found in the GIT repository under the following link:
(Please note that you have to download the HTML file to view it. Directly from the GIT repository this is not possible).

PCB ManufacturingAll infos you need for the production of the PCBs can be found here:

The materials required to set up the pxlDigit_clock

The required parts are briefly described in the following section.

The STL files required for 3D printing the housing parts can be found in the GIT repository under the following link.

How you can download files from a GIT repository is described in the following article.

You will then need the following parts for the assembly.

  • 3x assembled "slave" pxlDigit PCB
  • 1x assembled "master" pxlDigit PCB
  • 4x 3D printed housing
  • 3D printed base
  • 28x 3D printed diffuser made from transparent filament
  • 8x M3x8 cylinder head screw
  • USB breakout board
  • Wifi patch antenna with UFL connection
  • 3x 25cm cable 0.2mm² in (e.g.) red
  • 3x 25cm cable 0.2mm² in (e.g.) black
  • 3x 25cm cable 0.2mm² in (e.g.) green
  • 15cm cable 0.2mm² in (e.g.) red
  • 15cm cable 0.2mm² in (e.g.) black

Below you can see a few close-ups of the required parts.

Preparing the pxlDigit circuit boards for installation

First, you should connect the prepared circuit boards with the necessary connections and cables.

For this you need the four assembled pxlDigit boards. (3x slave version, 1x master version)

One board should be equipped with a USB-C connection, ESP and the electronics required for programming. The three remaining boards only need to be fitted with the LEDs or the necessary components.

You will also need the prepared cables.

  • 3x 25cm cable 0.2mm² in (e.g.) red
  • 3x 25cm cable 0.2mm² in (e.g.) black
  • 3x 25cm cable 0.2mm² in (e.g.) green
  • 15cm cable 0.2mm² in (e.g.) red
  • 15cm cable 0.2mm² in (e.g.) black

Then tin the connection pads on the pxlDigit PCB...

... with a little solder.

You should also prepare the cables by stripping the cable ends...

... and tinned with a little solder.

Then you can connect the cables as shown...

... solder with the pxlDigit PCB.

Repeat this for all "slave" PCBs (PCBs on which only the LEDs are fitted).

The PCB which is fitted with the LEDs and the electronics required for operation (ESP & Co) (master version) should then be soldered to the remaining two wires.

These two cables are only connected to the contacts

  • GND
  • 5V


Prepare the housing parts

You should now prepare the housing parts so that you can install the prepared PCBs in the housing parts.


For this you need

  • 4x 3D printed circuit board holders
  • the 3D printed base
  • 8x M3x8 cylinder head screws

You should first machine one of the circuit board holders a little. This will allow the USB-C connection and the connection cables to fit through the opening shown.

The finished circuit board holder could look like this.

Now you should insert two M3x8 cylinder head screws through the base as shown.

To make this easier, you can use the circuit board holder as a shelf.

Then screw the base to the circuit board holder as shown.

Other view.

Other view.

Repeat this step for all four circuit board holders.

Other view.

Install the prepared circuit boards in the housing

Now you can install the circuit boards in the brackets.

You will need the prepared pxlDigit PCBs and the prepared holder.

Attach the first (slave) PCB to the digit on the outside right and thread the cables through the openings in the housing as shown.

Other view.

Other view.

The data line which is connected to the LIN pin on the pxlDigit PCB (in this example the pink line) should then be threaded through the opening of the next PCB as shown.

Other view.

Then you can insert the PCB into the housing as shown.

Now repeat the previous steps for the next pxlDigit PCB.

Other view.

After you have threaded the wires through the openings as before, you can solder the data line of the previous PCB to the LOUT pin of the current PCB.

Other view.

Repeat this until you have all slave PCBs and the master PCB in position.

Of course, only the LOUT pin of the master PCB is connected to the data line of the previous PCB.

Other view.

Before you insert the master PCB into the holder, you should now connect the WiFi antenna.

To do this, guide the antenna connection cable through the opening in the bracket.

The UFL connection of the antenna should then...

... are connected to the UFL socket on the master PCB.

You can then attach the antenna as shown ...

... glue into the base.

Now you can already put all PCBs into the case.

At this point I recommend to test the setup already. You can already install the firmware and test that all LEDs are controlled correctly.

So that the PCBs are securely fixed in the holder...

... you can fix them with a drop of hot glue if necessary.

The current structure should now look something like this.

At this point you can combine the power supply lines as shown.

Then thread all the wires to the side of the master PCB.

To connect these lines to the USB Breakout, you should first connect the contacts

  • GND
  • VBUS

tin with a little solder.

Then you can connect the power supply lines as shown....

... solder to the USB breakout board.

Make sure that no short circuits occur to the neighboring contacts.

You can then use the USB Breakout Board...

... with a little hot glue...

... glue into the base as shown.

Other view.

Other view.

Other view.

At this point you should also do a small function test. The pxlDigit_clock should now be able to be supplied with power via the USB port of the breakout board.

Insert the diffuser

The light from the LEDs in the individual segments only really works well when it is evenly distributed. This is achieved very well by inserting diffusers into the housing.

For this you need the prepared pxlDigit_clock and 28 3D printed diffuser parts.

The insertion works very easily if you let the base of the case protrude over a table edge as shown.

Then you can insert the diffusers as shown. If they are too loose in the housing, you can also glue them with a small drop of glue in the housing.

Once you have all the diffusers in place, your setup should look like this.

Other view.

Other view.

In operation, thanks to the diffuser should then result in a uniform light distribution.

Program firmware

I am currently working on a simple Arduino library to control the pxlDigits. Until this is finished you can also use the pxlBlck firmware use. This already supports the LED matrix form of the pxlDigit and also offers useful functions for automation and control via WiFi or the serial interface. General info about the pxlBlck plugin can also be found here:

Information about the installation of the pxlBlck plugin can be found here:

Configure pxlBlck plugin

After installing the firmware you have to configure the plugin correctly. You can also find information about this in the article pxlBlck - Install and configure the pxlBlck plugin.

For additional orientation, you can also use the settings from the screenshot shown here.

pxlBlck Usecases

Articles are listed under the tag "pxlBlckUsecase" in which you can find examples of use. It also explains how you can configure your pxlBlck accordingly.

Animations, icons and commands

More information about the display of animations, icons and the possible commands with which you can configure your pxlBlck can also be found in the following articles.

Have fun with the project

I hope everything worked as described for you. If not or you have questions or suggestions please let me know in the comments. I will then add this to the article if necessary.
Ideas for new projects are always welcome. 🙂

PS Many of these projects - especially the hardware projects - cost a lot of time and money. Of course I do this because I enjoy it, but if you think it's cool that I share the information with you, I would be happy about a small donation to the coffee fund. 🙂

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