Tutorial: OSD Menu for RealACC Diversity Module & Fatshark Goggles Button Support

George Chatzisavvidis is very kind to share with us how he enabled OSD menu for the Fatshark Diversity module and goggles button support, by adding a minimOSD.

Github page and source code by George: https://github.com/gc9n/rx5808-Diversity-RealAcc-Compatible/releases/tag/V2.0. The steps and images are created by George, article is edited by Oscar.

By doing the following mod to your RealACC diversity module, and adding a micro minimOSD, you can enable the following features:

  • Added OSD support for menu
  • Ultra fast Real time RSSI feedback
  • Ultra fast Real time Diversity feedback
  • PAL or NTSC recognition
  • Goggles Battery voltage monitoring
  • Fatshark Buttons Compatibility (before the goggles’ buttons are useless when using diversity modules)
  • Favorites enhancement

Here is a demo video.

Warning: Due to the nature of this project, it’s possible that you can damage your unit, therefore do this mod at your own risk!

Software Instructions

Download the firmware for MinimOSD

MicroMinim OSD Fonts

In order to upload the fonts to Microminim OSD, the easiest method is by using the MW_OSD project.

microminimosd-ftdi

  • Connect the microminim osd to pc
  • Upload the MW_OSD.ino.hex to Microminim OSD
  • Open MW_OSD_GUI.exe
  • Connect to the MicroMinim
  • Font Tools > select the polyphemous_Charset .mcm
  • Upload
  • Done with Fonts

If you are not familiar with this process you can follow this video, and when you get to the part about fonts, you can choose polyphemous_Charset .mcm from the zip file.

PolyPhemus

Upload PolyPhemus.ino.hex onto MicroMinimOSD.

Preparation for RealACC Module

Upload the rx5808-pro-diversityGc9n.ino.hex.

Hardware Instructions

The Goggles FacePlate Mod

We have to power both the MinimOSD + diversity module with a separate power source rather than from the goggles, because the fatsharks internal voltage regulator is rated under 0.5A of current. In my humble opinion everyone that uses diversity module of any brand have to do this mod.

fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-2

fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-4

fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-6

fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-8

fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-9

fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-11

fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-12

fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-15

fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-17

fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-16

I added a L4941BDT-TR LDO (datasheet) 5v 0.5amp voltage regulator into the RealACC diversity module. This regulator is capable of working with input voltage close to 5V. For other regulators, in order to give 5V they have to take at least 7.2V, therefore L4941 is the way to go.

The L4941 Needs 2 capacitors: one ceramic capacitor, and one tantalum type capacitor (the line indicates the POSITIVE).

The ceramic capacitor goes between the output pin of the L4941 and ground (polarity doesn’t matter), while the tantalum electrolytic capacitor goes between the input pin of the L4941 and ground (polarity DOES matter! The little line is the positive so you have to solder it in VIN pin of the L4941)

I found a ceramic capacitor from an old CD ROM drive. I just used the one that fits physically. I scavenged a tantalum electrolytic capacitor from the same CD ROM drive also, I just cross check the letters and found from the internet that it’s rated for 10V (we use it for 2s – 8,4V max)

This mod doesn’t require opening your goggles so it will stay intact.

The Fatshark Goggles have an internal 5V voltage regulator that feeds the Video RX module with limited current. When powering both the RealAcc diversity module and micro minimOSD, the minimOSD simply doesn’t start.

Furthermore most of the current diversity modules on the market draws a very large amount of current which is stressing the internal 5V regulator already. You could put your goggles in danger if you push it even harder with extra 5V devices.

Therefore I wanted to find a different power source for the OSD module, but I don’t want to open the goggles or doing any modification ot them. Then I saw the fan on the faceplate! So I just took power from the balance plug that feeds the little fan. (I used those cables: I used those cables (affiliated link to support George)

Now the power for the module is independent, I can also get goggles battery voltage monitoring!

Voltage Regulator For Module

We scratch off the paint in this area carefully (it’s basically electrical ground) , and we solder the bottom (GND) of 5V regulator on to it.

fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-1

We apply solder, and we gather the regulator and the caps.

fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-voltage-regulator-cap

The legs of the regulator are lifted from the PCB of the diversity module.

fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-voltage-regulator-legs

Now if you look closer I also scratched two more pads on the diversity module PCB (ground) to solder the caps.

fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-voltage-regulator-sold

Now we apply solder on these pads.

fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-regulator-caps-ground

Tandalum Cap to VIN and GROUND.

fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-ceramic-cap

Ceramic to Vout and GROUND, soldering the positive and negative wires, the negative is the soldered on the back of the regulator.

fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-ceramic-cap-tandalum-cap

fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-connection-components

Video In and Video Out

This is the most important part, where you split the video in half and you give it to the OSD and OSD returns the Overlay .

Carefully start scratching the paint on this line.

fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-13

fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-20-1

Now separate this line, cut it in half , and connect to the OSD, see pic below.

fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-20-2

And looks like this.

fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-vin-vout

Cut the VCC pin from the RealAcc Module!!!

Schematics:

Important Note

You have to consider how you are going to connect the FTDI of the Micro MinimOSD (RX TX VCC GND). Ideally, it should be able to be disconnected from RealACC module easily, because if you want to upgrade your firmware in the MinimOSD or in the diversity module, The FTDI connection has to be disconnected. You can see in this pic that i insert female headers into the OSD, in order to remove it from the module easily.

fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-20-3 fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-20-11

fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-20-10 fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-20-9

fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-20-8 fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-20-7

fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-20-6 fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-20-5

fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-20-4 fatshark-fpv-goggles-realacc-osd-support-minimosd-diy-mod-connection

11 thoughts on “Tutorial: OSD Menu for RealACC Diversity Module & Fatshark Goggles Button Support

  1. Balazs

    Hi Oscar!

    How to put this osd mod for my DIY diversity receiver? Not Realacc fatshark module but also DIY diversity module! Wiring B0 B1 and B2 ?? Thank for the help!

    Reply
  2. flawi

    Is there a reason you say that the tantalum cap should be on the input side? All application notes and example schematics from the datasheet indicate the opposite, to use the 22uF tantalum on the output side, and a small ceramic cap on the input?

    Reply
  3. Nikolas

    Since this module : banggood.com/Realacc-RX5808-Lite-Open-Source-5_8G-40CH-Diversity-Receiver-for-Fatshark-Goggles-Plug-and-Play-p-1096128.html?rmmds=search
    already has an osd built in, is it possible to make a physical button to it for navigation (I’m not using a fatshark)

    Reply
  4. Freakshowdevil

    Wiring schematic on minimosd is wrong, gc9n has updated it on github
    github.com/gc9n/rx5808-Diversity-RealAcc-Compatible/blob/master/STEPS/STEP%20THREE%20(connections)/Realacc%20-%20MinimOSD%20mod%20.jpg

    Reply
    1. brkdwn

      Oscar you should really update the schematics with the one from github… It’s really confusing, I soldered and de soldered 2x times already beacause I though I had it wrong ;)

      good day !

      Reply
      1. Oscar Post author

        sorry about that.. the project author did not tell me when he updated the diagram :) updated now!

  5. think.help

    Sorry but I believe this article is lacking information and detail so anyone trying to follow the process is going to be doing a lot of head scratching.

    In order to upload the MW_OSD.ino.hex to Microminim OSD you can’t use the MW_OSD project as the article suggests as its a HEX file so something like XLoader is needed or use the MW_OSD projects MW_OSD.ino file instead.

    From there you will be able to use MW_OSD project to upload and write the font polyphemous_Charset.mcm

    Then once the fonts are done, use something like XLoader to upload PolyPhemus.ino.hex onto MicroMinimOSD and your MicroMinimOSD is now ready for action

    Happy to be corrected – fly safe

    Reply
  6. Robert Hoffmann

    Me bows to Oscar the electronics wizard ..nice job man !

    Now please send your article and plans to: LAForge, TrueD, and Realaac ..and lets see which one brings out a ready to buy commercial model for those not savvy or courageous enough to build this themselves ;-)

    Reply

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