|Number of pixels||144|
|Grayscales / Colors||512|
|Illuminant||SMD LEDs (size 0404)|
|Power input||? mW|
|Contact person||Arne Rossius|
TicTacLights Nano Colour is the RGB version of TicTacLights Nano, which also fits into a mini TicTac box. Just like the monochrome version, it uses a lithium polymer battery, alternatively it can be powered from USB. The LEDs are square and only 1 x 1 mm large.
This project uses the BlinkenPlus firmware on an ATmega162 controller.
The hardware is split onto two stacked PCBs, the main board and the power/data board. The main board (4 layers with blind vias) contains the LEDs, the microcontroller, the shift register ICs and the associated transistors and passives. It also contains the Micro-USB connector for mechanical reasons. The power/data board (2 layers) contains the USB to UART bridge IC, a switching converter (to generate the 5 V supply required for the RGB LEDs when using battery power) and battery charger IC as well as the MicroSD card slot. The two boards are connected through a 1.5 mm high fine-pitch connector.
Hardware revisions 1.0 and 1.1 (all kits sold before 2021) often have an issue at power-on, all LEDs remain dark. This is caused by the shift registers outputting "low" on all pins at power-on. This causes all MOSFETs to conduct, which puts all 18 pull-down resistors of 220 Ω each across the supply in parallel. The boost converter for the 5 V supply isn't able to start up with this much load, the output voltage stops rising when it reaches around 2 V -- not enough for the microcontroller.
This problem can be solved by increasing the pull-down resistors (R7~R11) to 470 Ω. A suitable type is e.g. Yageo YC164-JR-07470RL (available in single quantities from Reichelt with order code "BCN16 470" -- ignore their picture, it is wrong).
In Rev. 1.2, R7~R11 were increased to 470 Ω. PCBs and solder paste stencils remain unchanged.
- Schematic (PNG)
Only the solder paste stencils changed for Rev. 1.1.
- Stencils for main board (Gerber)
- Stencils for power/data board (Gerber)
- Schematic (PNG)
- PCB layout for main board (Gerber/Excellon)
- PCB layout for power/data board (Gerber/Excellon)
- Construction kit instructions Rev. 1.1
This project uses the BlinkenPlus firmware.