What are header pins and why do I need to solder them you ask?
Many kits you buy only come without the header pins on as it is easier to ship them this way. You need to solder the header pins on once you get the kit. Header pins allow the board to connect to other things like power, ground or sensors.
We bought a level shifter recently and needed to solder on the header pins. Before we get to that, here are some different header pins you may encounter.
Left to right in the photo above are Double Row Female Headers, Female Headers, Extra Long Female Headers, Male Headers, Right Angle Male Headers. The most common one you may solder is probably male headers.
I haven’t yet had a use for the double row headers. Many microcontrollers come with female headers already on them. Extra long female headers could be for soldering onto a shield that is then put onto the female header pins of a microcontroller. The male headers snap apart easily with a pair of pliers. Right angle headers can be useful if you want the bottom of a board to be flat and not have pins sticking out of it.
Soldering Header Pins
Here is the level shifter and male header pins I needed to solder. The easiest way to to this is with a breadboard.
Here I have put the header pins onto a mini breadboard.
Here the lever shifter is on the pins, waiting to be soldered.
First we soldered one pin in opposite corners to make sure the board stays flat on the pins.
* Now if you have a cheap soldering iron or are just inexperienced, keep soldering diagonally. Solder one pin on one side and then one on the other until done. The reason for this is to let the heat dissipate from the plastic around the header pins so you don’t melt it.
We soldered one row at a time but have a temperature controlled soldering station and some experience.
Now we have soldered one entire row of pins.
Here is a closeup of the soldered pins. I could use a little more solder on the pad of pin A4 but it should be fine.
Now we have soldered the other row. Gently pull what you have been soldering out of the breadboard.
Here is the level shifter all soldered and ready for a project. Need some extra header pins for your next project ? These 1×40 40pin 2.54mm Male Pin Header Strips fit on breadboards and are perfect for your next project.
* Thanks to @pocketmt for the tip.