OSD is a great addition to Multicopter FPV flying. In this article we will look into what an OSD is and the benefit of using it, how we connect OSD to our FPV system, and finally some of the options we have around OSD products and their features.
If you have any questions, please let us know by commenting down below.
What is OSD and the Benefits
OSD stands for On Screen Display. In our drone hobby, an OSD is a little PCB board that overlays flight information onto your FPV video. It allows you to monitor your quadcopter status in real-time while flying FPV.
If you have the appropriate sensors and OSD, you can display flight data on your FPV goggle or monitor, such as battery voltage, how much current your motors and other electronics are drawing, your altitude, GPS coordinates etc.
It makes FPV safer if you know your battery level when you should land, or the distance you have travelled and which way your should should head back.
OSD is not necessary for FPV flying, but as you canimagine it’s tremendously useful. Most people at least get a simple OSD to display LiPo voltage to avoid over-discharging their batteries (as you fly further away voltage alarm is hard to hear).
Types of data can be displayed by OSD
Here are some of the most common types of OSD data that are used in OSD.
Depends on the type of OSD you have, this could be flight time (from the second the multicopter takes off), or powering time (from the second the quad is powered on). Some OSD’s even allow multiple multiple timers.
Nearly all OSD units support voltage reading. This is regarded as the most essential piece of information when flying FPV, so you know when you should land (I usually land when voltage drops down to 3.5V per cell).
With current sensor you will be able to monitor how much current is being drawn from your LiPo battery, and the total mah of battery capacity used.
RSSI is the indication of your radio signal strength, usually displayed as percentage in OSD. The further you fly away the weaker the signal, with this info you know when you should head back.
RSSI is produced by the radio receiver usually in PWM format, so sometimes you need a digital to analogue converter such as a low pass filter.
Some OSD allows you to set up alarms, to alert you when user defined values have been reached, such as the battery voltage level, or RSSI being too low and so on.
Shows the current flight mode of your quadcopter. It’s useful if you switched frequently between lots of flight modes like Loiter, manual or self-level mode, so you don’t get confused what mode you are on. You probably need to be able to connect your OSD to your flight controller’s serial port to get this feature.
By using GPS, not only you get a coordinate of your drone, you also get altitude data (although it’s more accurate with barometer sensor or sonar sensor). Thanks to some clever calculations, you can also get the ground speed of your multicopter, the distance from the point where it launched, and home position (A graphical indication to which direction you should fly to get back, really helps with your orientation if you are lose)
This is a virtual horizon to help the user with roll axis balance.
OSD Connection with Camera / VTX / Flight Controller
There are 3 types of OSD I can categorize:
- Standalone OSD
- FC dependant OSD
- Hybrid type (can be standalone or/and FC connected)
Standalone OSD connects only to the camera and VTX, and doesn’t talk to the flight controller. It might also connect to GPS/other sensors directly if it supports them. A good example would be the Skylark OSD (GPS/Current Sensor) or Super Simple OSD.
FC dependant OSD relies on flight data from the flight controller, usually passed through serial port (RX / TX). On its own the OSD does nothing apart from overlaying text on the screen. The MinimOSD from Hobbyking is a good example (without any mod). One advantage of this type of OSD is, while OSD is getting flight data from the sensors on FC, the sensors can also be used by FC to assist flying. While in standalone OSD system, sensors/GPS connected to OSD cannot be used by flight controller.
Hybrid type OSD can be used as a standalone OSD (but might be limited in functionality). It can also be connected to the flight controller for richer range of flight data. The MinimOSD with KV team Mod is a good example: when used as standalone, you can display RSSI and voltage. But when used with a flight controller with GPS connected, you can display flight mode, GPS data, altitude and so on.
Here are some connection examples.
Simple Connection Example – Standalone OSD
As an example, this is the connection of Hobbyking Super Simple OSD, with FPV camera, video transmitter VTX, and a 3S LiPo battery.
In theory you can monitor a second battery on Bat2 port.
Advanced Connection Example – Hybrid OSD
Note that with this MinimOSD, battery voltage reading and RSSI are measured right on the OSD (although it’s also possible to connect both of these to the FC instead, and pass these info via serial port, both ways work just fine).
Of course you can also connect a GPS module to the Naze32 if you want GPS data like coordinates, home distance, home direction etc displayed on your FPV video.
OSD’s that I have Tried
MinimOSD with KV Team Mod
MinimOSD is my favourite OSD at the moment, and that’s what I am using currently. With the correct firmware installed, it can be used with Naze32, CC3D, Multiwii boards, APM and PixHawk. It’s very powerful as it can display literally any flight information as long as you have the appropriate sensors.
It displays all sorts of flight data with appropriate sensors.
Hobbyking and Banggood also sells MinimOSD, but they are the original version and don’t have the side pins for things like RSSI, voltage reading etc. I basically wouldn’t even bother with them, just get the one with KV Team mod.
With the latest firmware, you can even tune your PID with the OSD menu. Here is a tutorial on how to setup MinimOSD with Naze32.
Same as the standard MinimOSD described above, only difference it’s the tiny size. It doesn’t have the 12V to 5V voltage regulator though. People tend to power this board with 5V anyway due to regulator overheat issues.
It also can display everything with appropriate sensors.
BrainFPV is a flight controller that has built-in OSD system, which can be configure through the FC software client. it’s perfect for those who doesn’t want to mess with wiring, and desire a clean, compact FPV system.
The Skylark OSD can display GPS (coordinates, home distance, altitude, speed), current, battery voltage, timer.
It was my first standalone GPS OSD system. I was using KK2 at the time, and looking for an OSD that can show me “home distance”. Skylark OSD did the job well, and it usually found GPS satellites very quick. The OSD system comes with a GPS as well as a current sensor.
In the end I sold it as I moved to smaller size quadcopters, and I didn’t find GPS data very useful anymore.
Super Simple OSD
Like the name suggests, it’s super simple to connect and setup, and does the job well. it’s one of the very few simple OSD’s that does 2S-4S voltage reading.
Although the accuracy is not as good as the E-OSD (for lipo smaller than 4S)
it can only do battery voltage and timer.
I would recommend this OSD to anyone who want a simple solution, and only running 2S-3S on your multicopter. It’s also “hack-able”, by flashing it with customized firmware, you can display RSSI data with the BAT2 pin.
It can only do battery voltage and timer.
Let’s Get Back to the Bench!
That’s it for now. If you have any experiences with any OSD units please share them in the comments below.