Introduction: NeoPixel Driver Board

By Bantam Tools
About: Bantam Tools desktop CNC machines provide professional reliability and precision at an affordable price. (Bantam Tools was formerly Other Machine Co.)

Learn how to make your own NeoPixel Driver Board using the precise Bantam Tools Desktop PCB Milling Machine! In less than four minutes, you can mill a driver board that allows you to facilitate driving power to large arrays of NeoPixels. Let’s mill on!

Step 1: Gather Your Tools, Materials, and Files

TOOLS

Bantam Tools Desktop PCB Milling Machine

Computer with Bantam Tools Desktop Milling Machine Software installed

Arduino IDE software

Flat end mill, 1/32"

Alignment bracket

Soldering iron

Voltmeter

Diagonal wire clippers

MATERIALS

PCB blank, FR-1, single-sided

Tape, high-strength, double-sided

Screw terminals, 5mm, 2x1 (8)

Capacitor, 1000uF

Resistor, 470Ω

Screws, M3 (4) Used for mounting

Arduino Uno

Arduino Sketch

FILES

Neopixel-Driver-PCB file

Step 2: Set Up Your Job

Begin by attaching the alignment bracket to the spoilboard. Then connect the Desktop PCB Milling Machine to your computer and open the Bantam Tools Desktop Milling Machine Software. Under Fixturing, select Locate and follow the instructions on the screen. Using the alignment bracket will ensure that your board is perfectly squared in the front left corner. If you haven’t installed the alignment bracket before, follow the steps in this support guide.

With the alignment bracket installed, it’s time to set up your job. We’re going to run through this setup quickly. If you need more guidance on how to load your tool and enter information into the Bantam Tools Desktop Milling Machine Software, refer to the Light-Up PCB Badge project.

  1. Home the mill.
  2. Double-check to make sure it says Bracket under Fixturing.
  3. Under Tool, select the 1/32" Flat End Mill, load it with the bit fan attached, and locate the tool.
  4. In the Material dropdown menu, select Single-Sided FR-1.
  5. Measure and enter dimensions in the X, Y, and Z values under Material.
  6. Put high-strength, double-sided tape on one side of the PCB, and place it onto the spoilboard so it aligns with the right corner of the alignment bracket.

Note: Remember to account for the thickness of the high-strength, double-sided tape (typically ~ 0.006”). Enter this for the Z value under Plan Placement.

Step 3: Import Your File

Download the NeoPixel-Driver-PCB file. In the Bantam Tools software, under Plans, click Open Files and select the NeoPixel-Driver-PCB file. Then, select the 1/32" Flat End Mill. Your mill time will vary depending on the speeds and feeds recipe you use.

For this operation, we used the following recipe for the 1/32" flat end mill:

  • Feed Rate: 60 in/min
  • Plunge Rate: 15 in
  • Spindle Speed: 22,000 RPM
  • Stepover: 49%
  • Pass Depth: 0.010 in

If you’d like to adjust your speeds and feeds to match ours, click File > Tool Library > Add Tool. Name your new tools and then input the speeds and feeds recipe. You can learn more about customizing your Tool Library in our dedicated support guide. Then, click the button next to Parts to Mill so that “bottom” is selected.

Step 4: Start Milling

When you’re done setting up your file, click Start Milling.

Step 5: Solder the Components

Alright, time to grab your components and your soldering iron. It’s easiest to solder the components in the following order:

  1. 470Ω resistor
  2. 1000uF capacitor
  3. 5mm screw terminals, 2x1
  4. 5mm screw terminal, 3x1

The circuit board is split into two sides—power and ground planes—that feed into three terminal blocks, allowing for up to six lines of power injection. These extra points of power injection help mitigate any voltage drops throughout a large array of LEDs that you would see if you were to drive power from just one end. The board also features four mounting holes for M3 screws.

The 1000uF capacitor sits between the power and ground planes to prevent the NeoPixels from being damaged during the initial rush of current when powering on. The 470Ω resistor lies in series with the data line to prevent the first NeoPixel from being damaged due to signal spikes.

Note: This board is intended to be used with 5V microcontrollers. Controllers outputting 3.3V or similar (e.g., Raspberry Pi, Teensy) may require level shifting on the data line.

Step 6: Time to Test

Open the Arduino IDE and then click File > Sketchbook > Library > Adafruit_NeoPixel > strandtest sketch, to download Adafruit’s NeoPixel library. Once you’ve downloaded the library, you can then test your NeoPixel strip. Keep in mind that pin six is the default data pin.

When you’re done, test each screw terminal using a voltmeter. If they all check out, you can now program a custom lightshow!