The latest Raspberry Pi Zero W comes with wifi and bluetooth built-in at $10. Which is great because it makes it perfect o IoT projects. But if you had previously bought a bunch of Raspberry Pi Zero or want to keep the new Raspberry Pi Zero projects low cost, you probably will go with the option of adding WiFi easily and cleanly to your existing or new Raspberry Pi Zero boards; without adding much bulk to the compact board.
To add wifi you need to get the micro sized USB dongles that has supported chipsets to avoid the hassles of installing custom driver. There are plenty of options on eBay with prices varying from $2 to $5. The generic ones comes with just the marking of 802.11n marking on the dongle and usually looks like the following. A lot of listings mentions if the dongle is supported by Raspberry Pi or not.
I purchased couple of these on eBay few years back for my very early Raspberry Pi v1 boards and these work perfectly. These are advertised to have 150Mbps max speed. The size of the circuit board inside these dongles makes it very suitable to add wifi to Raspberry pi Zero boards without adding any bulk to the board. Here is how the board looks if you take it out of the plastic casing.
It is quite simple to disassemble these dongles. First you need to slide out the metal part. Then you will need to bend the square plastic frame a bit to slide out circuit board out of the plastic housing. And here is how the plastic casing looks when disassembled:
The following diagram shows how to connect the exposed USB connection pads on the USB dongle to the populated 5v, GND, D+, D- pads on the reverse side of the Raspberry Pi Zero board.
I soldered 4 pieces of very thin wires to the USB dongle’s USB connection pads first and sticked one layer of Kapton tape to make sure the parts on this side of the board does not make any contact on the parts on the Raspberry Pi Zero board when I am going to stick this board near the logo area of the Raspberry Pi Zero board using double sided tape.
Then I positioned the board on the appropriately on the Raspberry Pi Zero board and the double sided tape held it on position.
I ran the four wires between the two USB connectors on the Raspberry Pi Zero board to the other side of the board tightly to be soldered to the populated pads.
Then I soldered the wires tightly by cutting off excess to the populated pads on the Raspberry Pi Zero board following the diagram mentioned earlier in this post. Here is how it looks after everything is soldered.
I am quite happy with the final result as it looks quite clean and does not add any bulk to the nice sized Raspberry Pi Zero board; which allows you to use any available Raspberry Pi Zero case or maybe you can also download and 3D print case designs from thingiverse and enclose the board with camera etc. without any hassle of fitting everything in nicely. This installation also does not block any of the header pins.