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Project Notes

#483 WyLed!

.. when you allow an exploration of a chip (TM1638) to get a little out of hand! The WyLed free-form sculpture reacts to sound and blinks a 4-digit LED display. An ATTiny85 provides a little brain, and the TM1638 handles all input and output.

Build

Here’s a quick demo..

clip

Notes

I checked out the basic operation of the TM1638 in LEAP#481. This project tries to do something a little more interesting with the chip.

One thing led to another … and I ended up with a freeform sculpture that got a little out of hand!

Sound Detector

Sound input is detected with a circuit borrowed from LEAP#482 Electret Sound-level Trigger.

It provides a binary signal based on a preset threshold (adjustable with a pot). This is presented to the TM1638 as a “key” input via a 2N7000 mosfet.

LED Display

A 4-digit LED 7-segment display is used as a pair of “eyes”. For the display unit I have, the pin connections are as follows:

LED Module pin Function TM1638 pin
1 E SEG5/9
2 D SEG4/8
3 dp SEG8/12
4 C SEG3/7
5 G SEG7/11
6 D4 GRID1/24
7 B SEG2/6
8 D3 GRID2/23
9 D2 GRID3/22
10 F SEG6/10
11 A SEG1/5
12 D1 GRID4/21

Note: numbering the digits is pretty arbitrary - just need to follow a convention. In my case:

  • pins on the LED module are labelled D1-D4 from left to right
  • I have mapped these so that GRID1-GRID4 operate from right to left

Programming the ATtiny85

The WyLed.ino has some supporting classes TM1638.h and KeyController.h for interfacing with the TM1638, but does not require any additional libraries.

I used an ATtiny85 for the final build, and programmed it using the Arduino ISP.

See my notes on LEAP#070 for how this is done.

Construction

Breadboard

Schematic

Breadboard Build

Especially for moderately complex freeform builds, validation of a breadboard is a smart first step! Note that I switched the SPI pin connections for the final ATtiny build (more convenient for construction).

WyLed_bb_build

Freeform Build

Came together in separately tested modules. First the electret input..

build01_electrect_module

I’ve got some SMD TM1638 so I used a bit of perfboard to make wiring them up a little easier..

build02_electrect_and_TM1638_modules

Bending the display module to shape..

build03_display_module

Rabbit Ears? Why … beacause!

build04_rabbit_ears

Adding a little more bling to the base..

build05_rabbit_ears_lit

Final build…

Build

Credits and References

  • Titam TM1638 - info from the original manufacturer, Shenzhen Titan Micro Electronics Co., Ltd. (深圳市天微电子股份有限公司)
About LEAP#483 ArduinoATmelLEDTM1638
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.