Category Archives: How-To

Waterproofing Your Drone; Winter Is Coming

So today 11/16/2016 I get word of rain/snow on Friday 11/18/2016.  This will be the first snow of the season and made me re-double my efforts to get at least one wet capable multirotor up and running.  Last year I had terrible luck and blew out more components then sessions I actually flew.  Water and salt from the roads kills things quick.  There are a few options out there that I know of that work.  (Disclaimer:  You do this at your own risk.  I am not responsible for any damage due to this modification.)

1.) DryDrone – I know nothing about this product but it’s supposed to be tailored directly for use with multirotors.

2.) CorrosionX – Great in a pinch but leaves a nasty residue and attracts dirt and debris.  FliteTest did a great video on using it here.

3.)  Conformal Coating – Silicone is the best.  Not very durable but makes for easier rework if you have to solder through it.

4.)  Clear Nail Polish – Any nail polish will work but a thick coat of this should protect things well.  Not easy to rework anything after it’s on there though.

5.)  Epoxy – The longer set stuff works best but don’t expect to do any work easily on the electronics after it’s on there.

6.)  Liquid Electrical Tape – Works good to keep water out but very messy and doesn’t look very professional.

Now some things to keep in mind.  You want to coat all PCB’s exposed surfaces to give you full protection including ESC’s but do not put any of these things on your motors.  The motors will run even when under water as they are already insulated.  Hot glue does not work as it’s permeable and does absorb moisture and doesn’t provide a water tight seal.

Something else to keep in mind some of these products do not react well to certain plastics and can cause them to deform or start desolving/melting.  It’s always best to test them on something before hand to make sure you don’t have an issue.

Now if you didn’t treat your multirotor prior to getting it wet or maybe you missed a spot and it’s shorting out all is not lost.  Best practice is to:

1.) Unplug Battery

2.) Rinse off any salt or other contaminants with distilled clean water.

3.) Spray WD40 on the electronics

4.) Wait for it to dry out completely 24-48 hours in a warm dry place

5.) Rinse and clean off the WD40 residue with more clean distilled water

6.) Dry it out completely

7.) Power up and see what does and doesn’t work.

This wraps up what I know works and if you would like to add a comment or suggestion feel free to contact me at the links in this blog.

MinimOSD programming through your flight controller

OSD’s have come a long way since where I started with the MinimOSD.  They have added features and streamlined some of the interface but the problem with it was the inability to easily change a setting other than by the limited menu via stick commands or having to hook it up to a serial to USB adapter.  This was a major headache most people did not want to deal with and so OSD’s seemed to be a feature most didn’t want to bother with.

As of BetaFlight 2.4.2 a feature has been added called SerialPassthrough and this allows your flight controller to act as a bridge to anything you have connected to a UART on your flight controller. Ben Timby submitted a pull request after testing it on a modified version of BetaFlight. For those with a Micro MinimOSD or MinimOSD that means you can access and change the setting on the OSD via the USB port on the flight controller.  Now you can’t flash or update the firmware through this feature as that still requires an Arduino or USB Serial programmer but usually that’s a one time thing you do before you install it anyway.

Here’s how to do it (text version below video):


It’s actually very straight forward and simple once you understand what it’s doing.  You have 2 or 3 UART’s typically depending on the board.  UART is short for Universal Asynchronous Receiver/Transmitter (wikipedia) but basically for our use is a serial port with RX and TX pins or pads.  It’s what our flight controller uses to communicate to devices you connect (for example USB, SBUS, SmartPort Telemetry, OSD’s, GPS, etc).  What this new feature enables is it allows your built in USB to Serial adapter that you use on your flight controller to connect to things connected on the UART ports on the board using serial communication. Basically you send a command through the USB com port and it mirrors it on a UART that you specify with the command.

A few caveat’s you must know before doing this:

  1. UART 1 is typically reserved for the USB so if you have connected anything you want to access on that UART this will not work
  2. Depending on your setup you may need to power the device you are trying to connect to access it.  In my case I had to plug the battery in to give voltage to the Micro MinimOSD I had installed.

Here’s how you do it:

  1. Connect your flight controller to the USB on your computer.
  2. Open Cleanflight and connect to the flight controller while noting the com port it’s using.
  3. Goto the Ports tab and verify what UART you’ve connected your device to.
  4. Goto the CLI tab and type the following:  serialpassthrough (port) (baud)  NOTE:  Betaflight labels serial ports starting from 0 not 1 yet most flight controllers label UART’s starting with 1.  So when selecting your serial port you’ll typically take whatever the UART number is and subtract 1 to get the serial port it’s asking for.
    1. Example:  You have your MinimOSD connected to UART2 that you want to connect to you’ll need to type: serialpassthrough 1 11500
  5.  Power up the device you are trying to connect to if it’s not already
  6. You will see what looks like random characters start scrolling under the command you ran if it’s working properly.
  7. Disconnect and close cleanflight but leave all the connections as they are.
  8. Open up your software you use to configure it.  In my case it was MwOSD GUI.
  9. Select the port you noted in cleanflight being used to connect to your flight controller and connect.
  10. You should have read/write access now to the device.
  11. When you’re done all you need to do is reset the flight controller via reset button or unplugging USB and battery.  This will remove the serialpassthrough so you can once again access it via cleanflight.

I have only tested this with Micro MinimOSD and the original MinimOSD but as I understand it it will work with anything connected to the UART that supports programming through the RX/TX pins like GPS.

You can find me on slack in FPVChat if you have any questions under the username drkavnger99.