I created my project prototype with Arduino Micro and Adafruit Bluetooth low energy device.

Now I need to develop the prototype to production (like a small USB device). I just need Rx, Tx, 3V pin from Arduino Micro.

I started design with ATmega32U4, USB and BLE by using Fritzing IDE. I am confused with Arduino Micro parts like reset, bootloader and other pins. Is there any problem if I leave the unwanted pins from Arduino unconnected, for my project? Will it work correctly like a Arduino micro?

This is my first PCB design. Please help me to design a final PCB with the unwanted pins left unconnected.

  • Can you be more specific about what the problem is? Also, do you plan on sending the board out to be manufactured in one of those popular board fabrication shops online, or do you intend to build it yourself?
    – Ricardo
    Dec 24, 2015 at 11:05
  • Thanx. @Ricardo. Problem.is it need all part in arduino micro for my product production because I wana make my usb device is smallest as possible. And also I dont know where I connect 3.3 volt from regulator in atmega32u4. Please hrlp through schematic diagram. I try to design my self and send board ptoduction through fritzing Dec 25, 2015 at 16:14
  • How about using a RFduino SMT Module (www.rfduino.com) or something similiar?! Jan 29, 2016 at 10:00

1 Answer 1


I have started to look at the Arduino Uno schematics, which are free on the website. To make an Arduino is very simple, just need the chip, crystal, a few capacitors and that's it.

Try to copy the same schematics then add the Bluetooth to the RX and TX pins, but be careful about the 3.3V as you don't want to fry your Bluetooth module :)

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