Pretty bird VER.CC 2019


Pretty Bird ver. CC (2019) is an edition of 150 printed circuit boards and associated parts that was commissioned by Creative Capital for their 20th anniversary retreat celebration. Creative Capital covered the cost of materials and I donated my time to realize the project. The printed circuit boards were manufactured by PCBWay in Shenzhen, China according to my specifications.

The functional circuit design is based on my effort to electrically generate the “pretty bird” song made by a Carolina wren using simple and low-cost hardware (and I am pleased to report that the sound comes close under the right lighting conditions, as explained below). The central visual element of the board is a Carolina wren etched in exposed copper that has been electroplated with gold. The wren sits in a green and white forest defined by leaves and circuit traces. When the components are added, this forest effect is enhanced by the physical depth and texture that they create surrounding the bird. Hold the circuit board up to a light to enjoy a watermark effect thanks to the translucency of the raw FR4 board substrate (versus the opacity of surrounding copper and solder mask).

This work of art —a multiple— is complete regardless of whether the owner elects to assemble it, although soldering and electrifying the circuit manifests additional dimensions of the piece. I invite you to solder the circuit regardless of your skill level, so don’t be afraid that you will botch it. It remains a work of art regardless of whether or not your circuit “lives.” Pretty Bird ver. CC is an exploration of the spark of life in machines and biological organisms, both of which have a natural lifespan according to physical wear. The piece is designed to be framed and displayed dead or alive, with or without the components installed. As for framing, I recommend that you use no glass on the front, but glass for the frame backer so you can see both sides of the circuit as well as the watermark. Bamboo is my frame of choice for this piece.

If you have received an unassembled multiple, consider yourself lucky. The process to build this board is an experience in which you will discover (most of) the fundamental building blocks of electrical engineering: resistors, capacitors, transistors, and diodes. The resulting electronic behaviors are caused by analog oscillations, which is to say, the waveforms that create flashing lights and chirping sounds are entirely generated by the discrete hardware and circuit traces that visibly surround the bird. No hidden software or recordings are involved. I hope that you will gain newfound respect for computers and an even greater appreciation for birds.


Pretty Bird CC (2019) comes with the following electronic components (board reference in parentheses):

Quantity 1: 0.47 uF electrolytic capacitor (C6)
Quantity 4: 100 uF electrolytic capacitor (C8, C12, C13) *C3 is unused - leave empty
Quantity 1: 220 uF electrolytic capacitor (C10)
Quantity 1: 47 uF electrolytic capacitor (C9)
Quantity 3: 470 uF electrolytic capacitor (C1, C2, C11)
Quantity 1: 1N4148 general purpose signal diode (D4)
Quantity 7: Green light emitting diode aka “LED” (D1, D2, D3, D6, D7, D8, D9)
Quantity 1: 2x5.5MM power jack (J1)
Quantity 1: 8 ohm speaker (LS1)
Quantity 8: 2N3904 NPN transistor (Q4, Q7, Q9, Q11, Q12, Q13, Q14, Q15)
Quantity 2: 2N3906 PNP transistor (Q3, Q10)
Quantity 2: KSC945Y NPN transistor (Q2, Q6)
Quantity 2: 10 ohm resistor (R1, R12)
Quantity 2: 100 ohm resistor (R4, R10)
Quantity 3: 12K ohm resistor (R20, R23, R26)
Quantity 2: 10K ohm resistor (R16, R22)
Quantity 8: 1K ohm resistor ((R13, R14, R17, R19, R21, R24, R25, R28)
Quantity 2: 20K ohm resistor (R18, R27)
Quantity 1: 220K ohm resistor (R8)
Quantity 1: 470 ohm resistor (R7)
Quantity 1: 47K ohm resistor (R2)
Quantity 1: Light-dependent resistor (R3)
Quantity 1: On/off slide switch (SW1)
Quantity 1: 12 volt DC power supply with minimum 300 mA. You must supply your own.

Extras: I made two small edits to the circuit after the boards were manufactured. These changes are not essential, but they do give a nicer chirp quality in my opinion. Scroll to the end of this page for these instructions.

Many of the electronic parts are small and can be difficult to tell apart. To distinguish between different resistor values, you may need to measure with an ohm meter (also known as a multimeter). This instrument is available at any makerspace or university laboratory, or you can purchase one from a hardware store. The transistors all have a black “TO-92” package, so you will need to read their tiny labels to tell them apart. A magnifying glass might come in handy.

Make sure you respect the polarity of all components! If you do not know what this means, ask someone with experience before you solder. The transistors, LEDs, diode, capacitors, and power jack must be installed in the correct orientation or the circuit will not work.

To solder the board, you will need:

A soldering iron (temperature-controlled is nice, but not necessary)
Solder (lead solder works best, but you need good ventilation)
Wire cutters are helpful.
You may need solder braid in the event that you make a mistake.


When the red power switch is in the “off” position, the green LED lights will blink in a pattern that is generated by a series of analog electronic oscillators. When the switch is flipped to the “on” position, you will hear sounds associated with these same oscillations —reminiscent of a chirping bird. In the upper left corner of the circuit board, there is a light-dependent resistor. I invite you to experiment with the quantity of light “seen” by this sensitive component (for example, block ambient light with your finger, or shine a bright flashlight thereon). The blink rate of the LEDs and the quality of the bird’s chirp will change under different lighting conditions due to changes in the resistance and, consequently, the frequency of oscillations. If you get the lighting conditions right (at the right time in the oscillation pattern), the circuit will make a sound that is reminiscent of a wren’s “pretty bird” song.


Solder an additional 1K resistor in parallel with the resistor at position R19, and
solder an additional 20K resistor in parallel with the resistor at position R23.

(If you must know why: the LEDs that I used during development drew more current than the LEDs that I used in the final board assembly. These hacks compensate for the change.)