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!
Download the firmware for MinimOSD: MW_OSD.ino.hex
MicroMinim OSD Fonts
In order to upload the fonts to Microminim OSD, the easiest method is by using the MW_OSD project.
- 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
- 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.
Upload PolyPhemus.ino.hex onto MicroMinimOSD.
Preparation for RealACC Module
Upload the rx5808-pro-diversityGc9n.ino.hex.
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.
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 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.
We apply solder, and we gather the regulator and the caps.
The legs of the regulator are lifted from the PCB of the diversity module.
Now if you look closer I also scratched two more pads on the diversity module PCB (ground) to solder the caps.
Now we apply solder on these pads.
Tandalum Cap to VIN and GROUND.
Ceramic to Vout and GROUND, soldering the positive and negative wires, the negative is the soldered on the back of the regulator.
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.
Now separate this line, cut it in half , and connect to the OSD, see pic below.
And looks like this.
Cut the VCC pin from the RealAcc Module!!!
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.