Published May 4, 2026 © MIT

Transparent Arduino UNO | Flex PCB Build

I designed and built a fully transparent Arduino UNO‑compatible board on a flexible PCB; no copper pours, no hidden layers.

IntermediateFull instructions provided2 days12

Transparent Arduino UNO | Flex PCB Build

Things used in this project

Hardware components

Microchip ATmega328

SparkFun Serial Basic Breakout - CH340C and USB-C

M5Stack ISP USBasp Programmer (Random Color)

Software apps and online services

Arduino IDE

CircuitMaker by Altium Circuit Maker

Hand tools and fabrication machines

Soldering iron (generic)

Solder Wire, Lead Free

Hot Plate, 800 W

Story

This is a fun project where you can literally watch the electrons flow (okay, not really, but you get the idea 😄).

This trensparent board runs standard Arduino sketches, includes a 3x3 NeoPixel array, and is reinforced with a 3D‑printed transparent resin frame to make the flex board rigid. The best part? All design files are open source and free.

👉 Watch the full video tutorial: https://youtu.be/bzEtKa5kXZA

👉 GitHub repo (all files): https://github.com/BEEMB/Transparent-Arduino-UNO

Sipplies list

PCB & Frame

Transparent flex PCB (JLCPCB)
Transparent SLA resin frame (JLC3DP)
PCB Stencil (custom size)

⚡Components

ATmega328 (with bootloader)
CH340 USB-to-Serial
3x3 NeoPixel matrix
NE555 timer IC
Resistors, capacitors, LEDs
Through-hole pin headers

Assembly Tools

Solder paste (Sn63/Pb37)
Fine-point tweezers
Mini hotplate
Soldering iron
Flux & cleaner
Epoxy (for bonding flex to frame)

Programming

Arduino IDE
USB-to-Serial adapter (e.g. FTDI)
ISP programmer (for bootloader)
USB-C or micro USB cable

FastLED library recommended

Design the Schematic & PCB Layout

I started in Altium Develop by creating a schematic based on the classic Arduino UNO.

Key choices:

ATmega328 as the main MCU
CH340 for USB‑to‑Serial communication
3x3 NeoPixel matrix for visual feedback
NE555 timer to drive a fading power LED

1 / 2

Then I converted the schematic into a PCB layout. The board outline matches the original UNO size. The most important rule? No copper pour regions! that would block transparency. I routed all GND and VCC nets as visible traces.

💡 You can explore the full design online via Altium 365 – check this link for access

Order the Transparent Flex PCB & Resin Frame

I uploaded my Gerber files to JLCPCB and selected (Download the GERBER Files from here):

Material: Flex
Substrate type: Transparent
Stencil: Yes (custom size)

1 / 2

A few days later, the iconic blue box arrived with perfectly manufactured transparent flex PCBs. You can literally hold them up to the light and see every trace.

For the rigid frame, I uploaded an STL file to JLC3DP with these settings:

Parameter Selection

Technology SLA (Resin)

Material 8001 Resin

Color Transparent

Finish 01 Oil Spraying

💡 You can get the board ready assembled from JLCPCB, you need the BOM and Pick&Place files to place an Flex PCBA order

Assemble the Circuit

Solder paste & placement : I taped the flex PCB to my desk, aligned the stencil, applied solder paste evenly, then carefully placed all components using fine tweezers. Double‑check the orientation of the MCU and CH340!

1 / 2

Reflow : I placed the board on a mini hotplate and watched the magic happen through a digital microscope. The paste melts, components settle into place, and a transparent board comes to life.

1 / 2

Through‑hole connectors : Soldered manually with a regular iron.

Bonding to the resin frame : The flex PCB is soft, so I glued it to the 3D‑printed transparent resin frame using a thin layer of epoxy. The result is a rigid, crystal‑clear Arduino board.

Program & Test

Burn the bootloader : Using an ISP programmer, I burned the Arduino UNO bootloader onto the ATmega328.

Upload sketches : In Arduino IDE, I selected Board: Arduino UNO and uploaded a simple Blink sketch. The onboard LED started flashing, success!

Then I uploaded a FastLED sketch to control the NeoPixel matrix. Colors cycle smoothly across the 3x3 grid, visible right through the transparent board.

🎉 That’s it, a fully functional, transparent Arduino UNO on a flexible PCB!

📁 Get the Files

All project files are open source on GitHub:

🔗 GitHub repo: https://github.com/BEEMB/Transparent-Arduino-UNO

Schematics

Code

FastLED Pixels test

#include <FastLED.h>

// How many leds in your strip?
#define NUM_LEDS 64 

// For led chips like Neopixels, which have a data line, ground, and power, you just
// need to define DATA_PIN.  For led chipsets that are SPI based (four wires - data, clock,
// ground, and power), like the LPD8806, define both DATA_PIN and CLOCK_PIN
#define DATA_PIN 9
#define CLOCK_PIN 13

// Define the array of leds
CRGB leds[NUM_LEDS];

void setup() { 
	Serial.begin(57600);
	Serial.println("resetting");
	FastLED.addLeds<WS2812,DATA_PIN,RGB>(leds,NUM_LEDS);
	FastLED.setBrightness(84);
}

void fadeall() { for(int i = 0; i < NUM_LEDS; i++) { leds[i].nscale8(250); } }

void loop() { 
	static uint8_t hue = 0;
	Serial.print("x");
	// First slide the led in one direction
	for(int i = 0; i < NUM_LEDS; i++) {
		// Set the i'th led to red 
		leds[i] = CHSV(hue++, 255, 255);
		// Show the leds
		FastLED.show(); 
		// now that we've shown the leds, reset the i'th led to black
		// leds[i] = CRGB::Black;
		fadeall();
		// Wait a little bit before we loop around and do it again
		delay(10);
	}
	Serial.print("x");

	// Now go in the other direction.  
	for(int i = (NUM_LEDS)-1; i >= 0; i--) {
		// Set the i'th led to red 
		leds[i] = CHSV(hue++, 255, 255);
		// Show the leds
		FastLED.show();
		// now that we've shown the leds, reset the i'th led to black
		// leds[i] = CRGB::Black;
		fadeall();
		// Wait a little bit before we loop around and do it again
		delay(10);
	}
}

Credits

DIY GUY Chris

57 projects • 358 followers

I'm having fun while making electronics projects, I am an electrical engineer in love with "Do It Yourself" tasks.

Transparent Arduino UNO | Flex PCB Build

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

Sipplies list

Design the Schematic & PCB Layout

Order the Transparent Flex PCB & Resin Frame

Assemble the Circuit

Program & Test

📁 Get the Files

Custom parts and enclosures

Resin Frame

Schematics

Schematic

Code

FastLED Pixels test

Credits

DIY GUY Chris

Comments

Embed the widget on your own site

Transparent Arduino UNO | Flex PCB Build

Transparent Arduino UNO | Flex PCB Build

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

Sipplies list

Design the Schematic & PCB Layout

Order the Transparent Flex PCB & Resin Frame

Assemble the Circuit

Program & Test

📁 Get the Files

Custom parts and enclosures

Resin Frame

Schematics

Schematic

Code

FastLED Pixels test

Credits

DIY GUY Chris

Comments

Related channels and tags