Both MinimOSD and Micro MinimOSD suffers from irritating technical problem. In some setups, they stops overlaying data during hard maneuvers or even right after arming. Problem is very simple: chip MAX7456 is extremely sensitive in terms of supply voltage quality. Working motors and/or servos, can introduce enough power supply noise to occasionally force MAX7456 to reset.
Luckily, solution is simple: separate LC power filter or big enough capacitor connected in parallel to 5V pads of MinimOSD.
Almost any big enough electrolytic capacitor will do (> 100uF, the bigger the better) but best results can be archived with low ESR > 500uF capacitor.
In my case symptoms were not very strong, usually only very fast flips caused MAX7456 to reset, but I’ve decided to go big: 1000uF low ESR capacitor.
Micro MinimOSD has 5V pads on a side and they are the best place to attach capacitor.
As you can see below, capacitor is bigger than MinimOSD itself and I had to think a little how to place it inside my Reptile X4R 220 frame.
Results are great: no more MinimOSD problems. OSD stays on all the time, no matter how hard I use the stics.
Last week I’ve been finally able to put my new mini quad into the air. It’s based on Reptile XR4 220 frame. Looks like I’ve succeeded with my build this time, since there were no major problems. Few minor, yes, but no major.
My Reptile X4R 220 mini quad has following specification:
Motors: EMAX RS2205 2300KV
ESC: FVT LettleBee 20A
Propellers: DAL 5040
Flight controller: SPRacingF3 clone running INAV with asynchronous gyroscope and accelerometer. I’ve already written few words about async gyro updates here
Radio RC link: ***FrSky X4R-SB***
Camera: Runcam Swift
VTX: TS5823S 200mW
Micro MinimOSD with MW-OSD 1.5
Here is short, uncut, video from maiden flight:
The only problem I’ve encountered, was with OSD. It stops overlaying data on aggressive maneuvers for a second and then OSD comes back again. Probably it’s because of voltage drop/noise. MAX7456 is extremely voltage quality sensitive. I will try to fix that with additional capacitor on 5V line this weekend.
When camera and minimOSD are connected to video transmitter, minimOSD is not overlaying OSD data. If camera is disconnected, OSD data is transmitted. After connecting camera, only camera image is transmitted.
Check if camera and minimOSD are using the same display system. Usually monitor/goggles and video transmitter does not care very much about used display system. Transmitter just transmits, and monitor/goggles very often can detect if signal is PAL or NTSC. But if camera is sending PAL signal, minimOSD has be overlaying imag using PAL subroutine. If it will try to use NTSC mode, it will fail. In case on MW OSD software (Scarab OSD), OSD display system is configured in GUI. Set it to the same system as camera.
Building a quadcopter without nice power distribution board always leads to the same result: state of total cable entanglement. It looks ugly, makes maintenance hard and adds unneeded weight. I will not show how my ZMR250 quad looked after I added FPV and OSD into it. Almost all space between top and bottom plate was taken by cables. Nightmare. So, after spending less than $9 I’ve become an owner of Eachine PCB Power Distribution Board w/ OSD Socket Support NAZE32 CC3D OSD For QAV250 Quadcopter from Banggood. This board did not have very good reviews, but offered three things I wanted: sockets for micro MinimOSD, integrated signal lines and low price. So, I gave it a try.
Few months ago I’ve wrote about my first handmade Depron airplane. It was cool design. Super simple, with KFm-2 airfoil, durable and easy to fly. But it had few serious flaws:
motor mounted in front of fuselage is great for flight characteristics, but propellers breaks all the time. Even with prop savers,
big fuselage is not the same as fuselage with a lot of space inside.
That’s why, I have build a second Depron airplane. This time with pusher propeller mounted on a tower behind wing. Wing is almost the same design as in my first airplane. It is still an KFm-2 (Kline-Folgeman, modified) airfoil, 150mm chord, 12mm thick. But is a little shorter: 1200mm instead of 1250mm. The main difference is inside wing. Instead of carbon fiber spars I’ve used two carbon fiber 6mm pipes. That gives plenty of stiffness. Wing almost does not bend in flight, even during hard maneuvers. And generates more than enough lift to give nice, slow flying experience without danger of heavy stall. You really have to want to stall it. And event when it stalls, it recovers nicely: drops a nose, dives for a second or two, and you have lift again. No need to work with rudder, just let it dive and gain speed and then level. Continue reading RedCruiser – DIY Depron airplane for FPV
While playing with newly arrived Micro MinimOSD and attempting to flash it with latest MW OSD software, I’ve discovered that offical tutorial, as well as many other are missing one tiny detail that makes whole process much harder than expected. In theory, MinimOSD just Arduino Pro Mini with additional hardware. So, in theory, you plug in your FTDI USB adapter and upload a sketch. But if you never worked with Arduino Pro Mini (like me, it was always Uno, Pro Micro, or barebone Atmega328) you might not know one detail. Yesterday it took me more than 30 minutes to figure out firmware upload is not working, while it should. So, another tutorial will be written.
To flash MW OSD to Micro MinimOSD we will need:
Micro MinimOSD with soldered pins, but isn’t this obvious?