The Arduino Nano was used for this demonstration as it has 5 volt GPIO pins and the lasers are 5 volt as well - so easy to wire up. Also, the lasers consume about 10mw each, which is just under the ...

The Arduino Nano uses a bootloader for handling programming the MCU, ... and has 2 more GPIO: pin 3 and 6 as D23 and D24 instead of another GND and VCC pins.

So this is how Charlieplexing technique can be used to control many LEDs using fewer Arduino pins. You can use this method to control more number of LEDs. For example, if you want to control 20 LEDs, ...

Note that the analogue pins A4 and A5 are reserved for the I 2 C bus, they have 4k7 pull-up resistors, and they are wired to both MCUs. This is also the case for the QSPI_CSn pin which is labelled REC ...

Eleven of the Nano’s IO pins plus 3.3V and ground are broken out to header pins that stick out of the 3D-printed enclosure, and the dongle is powered over the USB cable.

Both the Arduino Nano and Uno can be powered via their integrated USB connectors. This automatically supplies regulated 5V power to the board, allowing you to use any USB-supported power source ...