.. 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.
Here’s a quick demo..
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 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.
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|
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
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.
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).
Came together in separately tested modules. First the electret input..
I’ve got some SMD TM1638 so I used a bit of perfboard to make wiring them up a little easier..
Bending the display module to shape..
Rabbit Ears? Why … beacause!
Adding a little more bling to the base..
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)