HowTo: pxlBlck – Build your own pxlBlck_RingClock

Posted on 18. December 2020 by Fab

The pxlBlck_RingClock is very similar to the pxlBlck_SlotClock. It is also built using a 1 × 60 LED matrix and can display the time according to the same scheme as the pxlBlck_SlotClock.

However, the LED strip of the pxlBlck_RingClock is installed in a ring and not in a disc. This makes the design of the it even more unobtrusive. The microcontroller for control is built into the base of the pxlBlck_RingClock.

You have the choice between a minimalist base in which the ESP8266 is housed as compactly as possible. If, on the other hand, you want a little more stability and maybe even space for an RTC then you can also build the pxlBlck_RingClock with the larger base. If you also install the RTC, you can use the pxlBlck_RingClock without an active WiFi connection.

All information about how to build the pxlBlck_RingClock can be found in the following article.

Inhalte

Safety instructions

I know the following hints are always a bit annoying and seem unnecessary. But unfortunately, many people who knew it "better" from carelessness lost their eyes, fingers or other things or hurt themselves. In comparison, a loss of data is almost not worth mentioning, but even these can be really annoying. Therefore, please take five minutes to read the safety instructions. Even the coolest project is worth no injury or other annoyance. https://www.nerdiy.de/sicherheitshinweise/

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Requirements

For the assembly you have to master soldering tasks. The following articles provide tips on how to do this.

Required tools:

Required material:

In the following list you will find all the parts you need to assemble.

Overview

Here you can see a small overview of what the pxlBlck_RingClock can look like. As usual, the colors of the minute, second, hour hand and the hour marker can be set. The brightness of the hour markers and the hands can be adjusted independently of each other.

Collect the parts you need

So that you can start building your pxlBlck_RingClock, you should first collect all the parts you need.

To build the pxlBlck_RingClock you need the following parts.

WS2812 LED strip 144LEDs/m 60LEDs long
3D printed LED holder
3D printed base (there are different versions)
3x cables approx. 10cm long
1x Wemos D1 Mini
2x self-tapping screws 2×8
1x acyl glass ring inner diameter: 130mm, outer diameter: 141mm, Thickness: 3mm
2x M8x40 cylinder head screw

Another view of the ring parts.

You can find the STL files for printing on your 3D printer in the repository for the pxlBlck_RingClock under the following link.

https://github.com/Nerdiyde/pxlBlck/tree/main/platform/pxlBlck_RingClock

Screw the LED ring to the mini base

There are different versions of the socket. The socket shown here is the smallest of the available sockets. It only houses the ESP8266. (More doesn’t fit in there either). Due to its low weight, the pxlBlck_RingClock stands upright, but also tips over quickly. So you should only use this base if the planned installation site is level. As an alternative socket, there are sockets below, which can also be weighed down with weights. In addition, there is a little more space in one of these sockets. For example, an RTC (real-time clock) can also be integrated into this socket.

To do this, screw the base to the LED holder as shown. You can use the illustrated M2 screws including nuts or self-tapping 2×8 screws.

Another view of the screwed base with the LED holder.

Another view of the screwed base with the LED holder.

Prepare the LED strips

Before you can insert the LED strip into the base, you should solder the connection lines to it.

To do this, remove the insulation at each end 5mm.

Then put …

… the LED strip in front of you so that the arrow points away from you. This is important because the data input of the LED strip is on this side.

Now you should prepare the first contacts with some solder. This makes soldering the cables a little easier later.

Solder the leads, then as shown …

… to the prepared contacts of the LED strip. Cables are soldered to the following contacts.

Another view of the soldered lines.

So that the LED strip can be easily inserted into the LED holder, you should now carefully bend the red line so that all lines lead away from the LED strip in the same direction.

Important: Make sure that you do not stress the contact surface of the SMD strip too much. Otherwise it could happen that the wire including the contact surface tear off.

Close-up of the bent wires.

Insert the LED strip into the LED ring

After you have prepared the LED strip, you can now insert it into the LED holder.

To do this, guide the cables through the LED holder and the screwed-on base as shown.

Then you can start from the lower “6 o’clock position” to insert the LED strip into the LED holder.

The LED strip should be pushed into the LED holder as far as it will go.

Another view of the inserted LED strip.

Another view of the inserted LED strip.

Insert the acrylic glass ring

As a diffuser, you should now insert a suitable LED ring into the LED holder.

Put the diffuser on the LED holder …

… and press it evenly over the entire circumference into the LED holder.

The diffuser should ultimately sit flush in the LED bracket.

View of the structure so far.

Connect the ESP8266 to the LED strip

Your pxlBlck_RingClock should now look pretty much finished. However, the heart – the ESP8266 – for operating the clock is still missing.

For this you need the ESP8266. I do recommend using the Wemos D1 Mini here. The ESP8266 is installed on this.

You can now connect the Wemos D1 Mini to the prepared connection lines of the LED strip.

To do this, the LED strip must be connected according to the following scheme.

ESP8266	LED-Stripe
5V	5V
G	G
D4	DIN

Another view of the connected ESP8266.

Connect LDR to ESP8266

I recommend installing an LDR so that your pxlBlck-RingClock can also automatically adjust the brightness of the LED strip to the ambient brightness. This is a bit fiddly due to the limited space in the base, but ultimately it’s worth it. 🙂

For this you need an LDR and a “normal” (1 / W) 1k resistor.

Also, some heat shrink tubing (not shown in the picture) is very helpful.

Solder the 1k resistor then …

… as shown to the shown contacts on the Wemos D1 MIni.

So the resistor between GND and the input of the ADC is soldered. It functions as a series resistor to the LDR and forms a voltage divider in combination with the LDR.

Close-up of the soldered resistor.

Close-up of the soldered resistor.

You now have to solder the LDR between the contacts of the analog digital converter and 3V3.

For this you should protect at least one of the LDR contacts against short circuits with a shrink tube.

The LDR itself should then protrude approx. 5mm beyond the end of the Wemos D1 Mini board.

Another view of the installed LDR.

Slide the ESP8266 into the mini base

After you have connected the LDR to the Wemos D1 Mini, it can now be pushed into the base. But if you want you can wait and test the function first. To do this, just skip this part and program and test the pxlBlck_RingClock first. However, it is also no problem to take the Wemos D1 Mini out again later.

To slide the Wemos D1 Mini into the base, you should slide it into the base as shown.

Make sure that no SMD components on the Wemos D1 Mini are damaged or torn off.

You should be able to slide in the Wemos D1 Mini without much effort.

The LDR should peek out a bit at the end.

If you want, you can then bend the LDR up a little and “align” it even better with the ambient light.