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Project Notes

#441 Pollen8

Pollen8 is a freeform wire sculpture with LEDs driven by a light-sensitive 555/4017 counter circuit.

Build

Here’s a quick demo..

clip

Notes

“Pollen8” is an exploration of contrasts and patterns in a freeform wire circuit.

I was interest in playing with a design that avoided the harsh angularity of most electronic circuits, instead using graceful lines that attempt to mimic a more organic structure.

The second goal was to achieve a chameleon-like LED display, where the visual effect depends on the perspective of the viewer: random from some angles, but clearly sequenced from others.

I created this for the Hackaday Circuit Sculpture Contest.

The Main Frame

The skeleton is made with 0.9mm and 0.55mm copper wire. The idea started as a very rough sketch in a notebook, and improvised in 3D by eye.

build_bare_structure

The Beating Heart

At first I was thinking of embedding a microprocessor in the project, but eventually decided to keep it old school with a classic 555 timer and CD4017 decade counter combo.

I was thinking along the lines of crafting and electronic “stamen” for the plant. Building this itself became a pleasurable little side-project.

build_timer_unit

build_counter_unit

I liked the look of the “counter unit” so much, I went off on a little tangent for testing purposes. You can probably tell I was thinking it looked like some kind of sci-fi planetary sensing outpost..

counter_tower_tengent

Base

The base is made from some copper PCB stock and 3 cork coasters. It includes a CR2032 coin cell holder, switch and some external power connector pins.

build_base_1

Middle cork coaster has a cut-out for the wiring:

build_base_2

build_base_3

The finished base:

build_base_4

Circuit Construction

A very simple variation of the classic CD4017 counter with a 555 astable clock source. A light-dependent resistor provides some frequency variation depending on available light. The LDR ranges from around 1kΩ when in light to 10kΩ when in darkness, corresponding to a clock frequency range of perhaps 6.5Hz to 34Hz.

The two CD4017 counters are wired in parallel - mainly for symmetry in the final design. Up to 5 LEDs are chained from each counter output (not all pins are actually used in my final build).

Breadboard

Schematic

Pollen8_bb_build

Parts

The main electronic components:

Item Description
U1 555 Timer
U2,3 CD4017 decade counter
C1 10µF electolytic capacitor
R1 2.2kΩ
R2 10kΩ LDR
  ~ 25 yellow 0805 LEDs
  ~ 35 red 0805 LEDs
  lots of 0805 220Ω resistors - one for each LED

Wire stock:

  • 0.9mm copper wire - main structural elements
  • 0.55mm copper wire - secondary structural elements
  • 0.2mm magnet wire - LED and power connections

Putting it all Together

The final step in construction was to assmble the individual LEDs with their current-limiting resistor. these are grounded on the wire frame and connected to the CD4017 outputs with magnet wire. This proved to be an extremely finnecky process to the point that I was cursing myself for deciding on such a construction. The main problem is that soldering one connection can easily de-solder another if you are not careful!

build_led_detail

I tried a range of processes and eventually settled on first soldering the LEDs to the resistors, then adding the magnet wire, and finally attaching to the frame.

build_led_1

Half the LEDs were attached prior to inserting the central timer/counter unit. The rest were attached afterwards.

build_led_2

A close-up of the final construction from the front:

build_front_close

And from the rear:

build_rear_close

Demonstration

The circuit works nicely on a 3.3V coin cell, but can also take power from the two pins at the rear. It’s quite efficient (seems to draw < 5mA at peak), but I’ve been conservative with the LED current-limiting resistors - they are not driven very hard.

When viewed directly from the front, a distinct “runway lights” pattern is apparent in the LEDs. This is produced with yellow LEDs that are angled forward.

demo_front

When viewed from other angles, the LED display is more chaotic. This is mainly produced by LEDs angled outwards.

demo_side

Credits and References

About LEAP#441 LEDCMOS/TTL555 TimerCraft
Project Source on GitHub Return to the LEAP Catalog

This page is a web-friendly rendering of my project notes shared in the LEAP GitHub repository.

LEAP is my personal collection of electronics projects, usually involving an Arduino or other microprocessor in one way or another. Some are full-blown projects, while many are trivial breadboard experiments, intended to learn and explore something interesting (IMHO!).

The projects are usually inspired by things found wild on the net, or ideas from the sources such as:

Feel free to borrow liberally, and if you spot any issues do let me know. See the individual projects for credits where due. There are even now a few projects contributed by others - send your own over in a pull request if you would also like to add to this collection.