EZ-WifiBroadcast. First set up and initial testing

Rusty Sun, 07/22/2018 - 19:18

So as promised here is my first take at EZ-WifiBroadcast. As described in a recent blog post EZ-WifiBroadcast. Affordable HD FPV? , EZ-WifiBroadcast is a DIY solution to have high definition FPV video for a relatively affordable investment of money and some of your time.

EZ-WifiBroadcast - Collection of parts.

What is the parts list? It is not too bad really, this is what I am starting out with.

  • Raspberry Pi Zero (air side tx) ($5)
  • Raspberry Pi Camera (~$20)
  • Raspberry Pi 3B (ground side rx) ($35)
  • 2x TP-LINK TL-WN722N v1, one for each Raspberry Pi (version is important, only v1s work at this time) (2 x $20ea)
  • 2X adjustable voltage regulators to supply 5.2V to the Raspberries anf WiFi dongles (2 x ~$2ea)
  • Ground Station monitor that has HDMI input, and HDMI cable. (I have a RMRC Black Pearl that I am going to use)
  • Misc wire and connectors, depending on how you decide to wire everything up

EZ-WifiBroadcast collection of parts

As you can see, the collection of parts is not too bad, and not really expensive either, So far I am in for around $100 , minus the monitor. I will 3D print a case for the air side Raspberry Pi Zero and WiFi card, but likely use a premade case for the ground side equipment, for now. So lets get to it.

Preparing the WiFi dongles for EZ-WifiBroadcast

The ground side, receiver side, really doesn't need any prep.I am just going to plug the WiFi Dongle into one of the USB ports on the Raspberry Pi 3B, and that's it.

The air side, transmit side, requires a little work, but it's not too bad. In an effort to save weight and space, I am going to de-case the dongle. For the TL-WN722N  it is pretty easy, there is a seam along the outside of the case, just use a flat tool to wedge in there, such as a flat blade screwdriver, flat pry tool, or just a household butter knife, even a slim coin should work. Once the case is popped off the circuit board will just come out. make sure you save all the parts in case you want to re-case it for use elsewhere later.

For a permanant install I would remove the USB plug and just wire directly to the circuit board but, if testing goes well, I plan on using this dongle as a second receiver on the ground side for diversity, and use a higher power card for the transmitter. So to preserve that capability I will leave the USB port on, but still wire directly to the board.

Powering the modules for EZ-WifiBroadcast

Power for both the Raspberry Pi Zero and the WiFi dongle (the transmit side of the system) will come from one of the adjustable voltage regulators. The regulators are capable of 3 - 40V input and 1.35 - 35V output, and at least 3A rated. Minimum input voltage is 1.5V over your required output. This will vary depending on what you get for voltage regulators, just be sure they are capable of a minimun of 5.2V and 3A output and have a convient voltage input level. As this transmitter is destined for an aircraft with a minimum of a 3S Lipo battery (~ 9.9V min) I should be ok.

Wireing it up is pretty simple, Solder the input wires with a connector of your choice, I am using JST connectors as they are popular for powering accessories in RC aircraft. Once you have power to the voltage regulator, and before wiring to the other components, adjust it to give an outpuit of 5.2 volts. Once the output is set correctly wire a positive and negative wire to each board. See picture for where to solder the connections. Once you have the power wired up it's time to wire up the data connection, again , follow the pictures.

EZ-WifiBroadcast TX side wired up