I have soldered together an Adafruit Motor Shield (Version 2) following these instructions for standard headers (non-stacking headers). The end result looks similar to the image below: Motor Shield

I'm hooking the shield to an Arduino Uno and I want to hook up some sensors to this shield as well. Unfortunately, the standard headers that I've soldered on don't allow me to do this. I see two rows of holes next to the ones I've already soldered, numbered 0-13 on the digital I/O and 0-5 on the analog I/O. Can I solder female headers onto these holes in order to enable them? Are there any pins that I can't/shouldn't use? I've heard a rumor that the motors use up some of the pins, but I can't find any information as to which pins to avoid, specifically.

Any help would be greatly appreciated.


Adafruit is very good at supporting their creations, including the shields. Look for the schematic for the shield on the product page. It will show which pins are in use. You can then use any other pin.

Those second rows right by the headers are connected (check with a multimeter to be sure), and using them as alternatives are what they are there for.

  • \$\begingroup\$ An excellent recommendation. I've found this schematic, but I'm afraid my skill at reading them is a bit limited. I can't really tell which pins are used and which are free just by looking at it. If you can discern them, please let me know. \$\endgroup\$
    – Paul
    Mar 16 '14 at 17:50
  • \$\begingroup\$ @paul digital 9, 10, analog 4, 5, and i2c sda and scl (which can be used by other i2c devices as well because they are a bus). Notice those are the only ones in the schematic that are connected to something else. \$\endgroup\$
    – Passerby
    Mar 16 '14 at 17:57
  • \$\begingroup\$ Thanks! So, I should definitely avoid hooking a header (or anything else) to digital 9,10 and analog 4,5; or else I risk shorting something out. Am I correct to assume so? \$\endgroup\$
    – Paul
    Mar 16 '14 at 18:28
  • \$\begingroup\$ @paul you can solder in a header to them, just don't use them. Analog 4 & 5 are tied to the i2c sda/scl pins, and digital 9 & 10 are for the servo 1 & 2 pwm. Tho If your code doesn't use servo 1 and/or 2, you could use them. \$\endgroup\$
    – Passerby
    Mar 16 '14 at 19:04

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