TicTacLightsEnglish

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project overview
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Tictaclights-operating-crop.jpg
Year 2012
Number of pixels 144
Grayscales / Colors 8 Grayscales
Illuminant SMD LEDs (size 0805)
Power input 300 mW
Contact person Arne Rossius
Project website

The TicTacLights is a very small BlinkenLights|BlinkenLights clone which fits inside a small TicTac box. The first revisions were powered by a CR2032 button cell battery. Battery life is only about 30 minutes. Newer revisions can be powered though a Mini-USB socket (not Micro-USB!) and have connections for a lithium-ion battery on the board (must be charged externally).

This project uses the BlinkenPlus firmware on an ATmega8515 controller. The PCB has pads for a Micro-SD card slot and solder pads for a serial port (RS232-compatible with external level converter, e.g. MAX3232).

The kit sold at 29C3 has a wrong setting for the low fuse byte. The correct setting is 0xFF (all bits not programmed). The fuse bytes can be changed with an AVR programmer and an external 5V supply (remove SD card before applying power!).

Hardware

The hardware is kept very simple because there isn't a lot of space on the PCB. The columns are directly connected to the controller's outputs, so large currents are not possible. Due to the high internal resistance of the button cell battery, the voltage drops quickly, causing the controller and the SD card to operate outside of their specifications (which requires a minimum voltage of 2.7 V).

Rev. 4

On-board USB to UART converter CH340G. Power supply through USB or with lithium-ion battery.

Rev. 3

Powered by USB or lithium-ion battery. Button cell holder removed.

Rev. 2

Can be powered by USB or button cell.

Rev. 1

Alternative Power Supplies

To supply the TicTacLights Rev. 1 from a different power source, one of these additional circuits is required:

Photos

http://arne.blinkenarea.org/TicTacLights/gallery.htm