# Solder the Header pins on the Pi Zero W

You will need header pins to access the GPIO on the Pi.  GPIO is needed in order to connect to the Pi via the MicroUSB cable.  [Details on what the GPIO pins do](https://www.raspberrypi.org/documentation/usage/gpio/)


1. Read the helpful guide on soldering: [Soldering is Easy Guide](https://mightyohm.com/files/soldercomic/FullSolderComic_EN.pdf)
1. No really, read the comic [Soldering is Easy Guide](https://mightyohm.com/files/soldercomic/FullSolderComic_EN.pdf). The teaching staff will make fun of you if you don't read it before you try doing it for real.
1. Apparently reading is hard because some people still haven't looked at the comic.  Go to [Adafruit's guide on soldering](https://learn.adafruit.com/adafruit-guide-excellent-soldering/tools) which includes videos.
1. Mount the raspberry Pi zero into a Panavise or other mechanism to hold it steady.  If none of those are available, you can use tape to stick it to a piece of cardboard, then stick that to the table.  Be aware the tape will melt or burn if it comes into contact with the soldering iron.
1. Get the dual row pins: 2x20. The pins are available in the stock room of V207 if they weren't included in your kit.
1. Drop them in from the top of the PCB and hold them in place. The short ends go into the PCB.  Wrap a piece of electrical tape from one edge of the PCB across the center of the tall pins, to the other edge.  This should temporarily secure them to the PCB.   Flip the board over.  The pins should just be sticking a little bit out the bottom of the board.
1. Heat and apply solder to the pins on the end (away from the tape).  Check that the solder joints are cool and strong, then remove the tape.  Finish the rest of the soldering.
1. Inspect the soldering joints under the microscope to make sure that there are not holes or anything else that might result in a flaky connection. If you see "spiky things" sticking out, that means you didn't heat the pin and solder enough.
1. If any of the connections look questionable, remove the solder on that joint and do it again.   **Unreliable solder joints will cause your system to be flaky which will drive you crazy later in the semester!**
