HowTo: Electronics – nanoPxl V1.1 soldering SMD components

I am currently working on the first preparations for a somewhat larger project. For this I need LEDs which shine a little brighter.

At the same time, I didn't want to forego the comfort of the well-known WS2812 aka Neopixel LEDs.

For those who haven't heard of it yet: These have the great advantage that they can be connected to each other like a kind of shift register. This means that only one GPIO of the microcontroller is used to control up to 512 LEDs. Nevertheless, every single LED can be individually adjusted in terms of its brightness/color.

Unfortunately, the WS2812 LEDs are currently only available as a 5050 SMD version. These can be fed with a maximum of 20mA per color. The brightness isn't bad. But it could be a little low for lighting under direct daylight.

That's why I designed the nanoPxl mentioned here. I took the original idea from kd_technology and then modified it a bit.

The 5730 LEDs used have a forward current of 180mA. So they are correspondingly brighter. 🙂

In the following first a few impressions of the assembled nanoPxl and the instructions for rebuilding.

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.

Affiliate links / advertising links

The links to online stores listed here are so-called affiliate links. If you click on such an affiliate link and store via this link, receives a commission from the online store or provider concerned. The price doesn't change for you. If you do your purchases via these links, you will support in being able to offer further useful projects in the future. 🙂


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

Electronics—My friend the soldering iron
Electronics - soldering THT components by hand
Electronics - soldering SMD components by hand

Required tools:

Required material:

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

PCB production: You can find all the information you need to manufacture PCBs here:

Collect the parts you need

Before you can start building your nanoPxl, you should of course have the required parts together.

You need the parts shown to assemble a nanoPxl.

Of course you only need one circuit board per nanoPxl.

View of (part of) the required components.

  • 1x WS2811 IC
  • 3x 5730 SMD LEDs (each red, green and blue)
  • 6x SL2302 N mosfet
  • 2x 13ohm 1206 SMD resistors
  • 1x 18ohm 1206 SMD resistor
  • 6x 10k 0805 SMD resistors
  • 1x 100nF 0805 SMD capacitor

Front view of the PCB.

Front view of the PCB.

Apply solder paste

Soldering the SMD components always starts with the application of the soldering paste. You can do this with a stencil or manually with a syringe including a suitable tip.

I did this with a syringe as shown here. To do this, apply a small amount of solder paste to each SMD pad.

Place components on the front

The board is populated on both sides. I started with equipping the LED side.

To do this, place the LEDs and resistors in the appropriate position as shown.

Make sure that you put the right LED color in the right position.

As soon as the 0805 10k resistors are in position, you can now also apply the series resistors of the LEDs.

These are the two 13Ohm and the 18Ohm resistors.

Then only the SL2302 N-Mosfets remain.

And that's it with the placement of the components on the first page. Now you can solder the components. You can see this in the following video.

Solder components on the front

The easiest way to solder the applied components is with the help of a hot air gun. Heat the components as shown in the video. I used a temperature of 250°C for this. If in doubt, you should always observe the information in the data sheet for the components.

Your board should then look something like this when soldered.

Another view of the soldered components on the front.

Another view of the soldered components on the front.

Another view of the soldered components on the front.

Another view of the soldered components on the front.

Another view of the soldered components on the front.

Place components on the back

After the front, the rear is now equipped.

To do this, first apply solder paste to the corresponding …

… SMD pads. Be careful not to apply too much solder paste.

Once you've applied the solder paste, you can put on the components to be soldered.

Pay attention to the orientation of the IC. The point in the corner of the IC must be congruent with the position of the point on the PCB.

Close-up view of the applied but not yet soldered components.

Solder components on the back

You can now solder the components on the back in the same way as you did before soldering the components on the front.

View of the soldered components on the back of the nanoPxl.

View of the soldered components on the back of the nanoPxl.

View of the soldered components on the back of the nanoPxl.

Control of the nanoPxl

Since the nanoPxl uses a WS2811 to control the individual LEDs, you can connect and control the nanoPxl in the same way as you are used to from the WS2812 aka Neopixel LEDs. 🙂

Each nanoPxl must be connected to 5V and GND. The data lines are then connected to one another from DOUT to DIN.

In the video you can see eight linked nanoPxl in action.

code samples

A library with which you can control the nanoPxl is, for example, the Neopixel Library from Adafruit. You can find them here:

Sample code that makes the first test easier can be found here:

Have fun with the project

I hope everything worked as described. If not or you have any other questions or suggestions, please let me know in the comments. Also, ideas for new projects are always welcome. 🙂

P.S. 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 appreciate that I share this information with you, I would be happy about a small donation to the coffee box. 🙂

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