Introduction: Brushless Gimbal for Aerial Photography Drones

Every self-respecting drone used for aerial photography needs a gimbal. Good gimbals are very expensive, cheap ones are not smooth. Brussless Gimbals (BLG) to the rescue! In there recent months there has been a flurry of activity around this new way of building camera gimbals. Instead of servo motors, a BLG uses re-wound Brushless RC motors in a direct drive configuration.

The cheapest of all BLGs on the market today (and readily available) is the GoPro BLG and Controller (Martinez v1) from RcTimer. Unfortunately that gimbal comes zero, zilch, nada instructions. Also there were some incorrectly machined parts. Hence building it can be quite a challenge. This Instructable is meant to fill this gap. Also it might give you enough pointers to design and build your own gimbal from scratch.

Testing of finished gimbal:



Timelapse video of the build:

Step 1: The Parts

Here's everything out of the package. There was one bolt missing. Be careful with the bag that contains the grub screws and C rings.  They're really tiny.

Step 2: Build the Camera Cage

It's pretty simple, just bolt the pieces together.

Be sure that the grub screw holes both face forward. A GoPro should friction-fit in the frame pretty securely. Use Loctite on the screws or they might loosen and get lost quickly.

Step 3: Assemble the Outside Frame

Oops, a problem! The side mount bolt hole was not properly beveled, so the bolt does not fit through the hole with enough length to attach to the edge piece.

We drilled a bevel using a larger drill bit. That fixed the problem nicely.

Step 4: Install Pitch Motor and Bearings

Next, assemble the bearings. Careful with the little pieces!

We found a problem with the grub screw hole. It wasn't properly tapped, so we couldn't get the grub screw inserted all the way. After some debugging, we ended up switching the two sides, so the working grub screw was on the motor side.

The grub screw uses a 1.25mm hex wrench. It would be nice if RC Timer included one. They don't, so be sure and have one ready.

Step 5: Yaw Motor

Make sure you have the indentations properly aligned. Dry fit it together to make sure.

One of the tapped holes was a bit malformed, and the 3mm bolt didn't fit through. You can clean it out with a 3mm drill bit, or tap a 3mm bolt through the hole with a hammer a couple of times. As good as new!

Step 6: Build Mounting Arm

-Attach the yaw arm to the frame mount.
-Attach the 3mm nylon risers to the frame mount.
-And then attach the board to the risers.
-And attach to the bottom plate of the anti-vibration unit.

Stick the rubber anti-vibration grommets onto the top and bottom plates. Do this after attaching the bottom plate to the gimbal.

Step 7: Solder the Motor Wires

Soldering is pretty simple. Snip the wires and re-tin them with a generous portion of solder. Tin the motor pads. Put each wire on the corresponding solder pad, and touch the wire with the soldering iron, attaching the wire. If it takes more than a second you're doing it wrong. Note that since this is a three-phase motor, the order of the wires doesn't matter.

Later you can cover the soldered connections with hot glue for physical strength and to insulate the wires.

Step 8: Connect Everything for Testing

This picture shows the correct orientation of the IMU and the correct connection of the pitch and yaw motors. We did this all wrong at first (due to lack of documentation) and the gimbal did a Harlem-Shake instead of image stabilization.

Note that we were doing the power wrong!  Don't use a 5V servo connection, use a 2S-4S battery. Be sure and watch the polarity. It may not be a bad idea to put a battery connector onto the board.

Step 9: Mounting the BLG and First Test

This nifty little sawhorse was sitting around from another project, and it made a perfect test mount.

If everything was set up correctly the BLG should behave like this:

Step 10: Harlem-Shake

This is what happens if the IMU orientation or the motor connections are wrong:









Here's what happens if you plug in the USB and forget to hook up the battery. There's enough power over the USB to power the processor. Not enough to power the motors, but enough to make them twitch.

Step 11: Mount on Your Drone / UAV / Quad / You Name It...

My airframe of choice at the moment is the TBS Discovery. I bought the leg extensions to give me enough clearance for the Gimbal. Without the controller board stack there seems to be just enough clearance. The upper mounting point can be screwed directly to the bottom of the TBS Discovery frame at an existing mounting point. It needed a M3 screw that is just a bit longer. The vibration grommets are too soft for the weight of the GoPro. I filled them with silicon to stiffen them up. Other people have stuffed them with earplugs ;)

Step 12: Software Setup

I got my controller board  to work out of the box without a firmware upgrade. The installed firmware is 0.48, however we could not get that version to talk to the 0.48 GUI. Mark managed to install 0.49 and that version talks to the GUI. But now we need to re-tune the PIDs. Below is the process for upgrading to 0.49:

Drivers

MAC:  You are in luck! It seem like the correct driver is present without any additional action.

Windows: You are entering a world of pain. The auto-detection will install an incorrect driver that is hard to uninstall. Do not plug in the board without having downloaded the correct driver and then disconnect from the internet. These instructions seem to be very thorough and worked perfectly on my Windows 7 PC: http://www.rcgroups.com/forums/showthread.php?t=1872416

Required software

To build the software, you need two things:

- Arduino software environment:  http://arduino.cc/en/Main/Software
- Brushless Gimbal software: https://code.google.com/p/brushless-gimbal/downloads/list

Build and install

Building and downloading the firmware is pretty straightforward:

1) install the Arduino programming environment.
2) load the gimbal software in the Arduino environment
3) ensure your configuration is correct:
    - in Tools / Serial Port, be sure your USB port is selected
    - in Tools / Board, Arduino Pro or Pro Mini (5V, 16MHz) w/ ATMega328 
4) Upload (arrow icon in toolbar)

If everything works, you will get a message regarding memory size and a message that the new firmware has been uploaded.

You should now be able to connect with the 0.49 GUI and start tuning. Note: Com port must be 1-10 of the UI does not work. You can change the com port in the advanced settings using the device manager.


TO BE CONTINUED WITH PID SETTINGS...

Step 13: Connect Controller With RC

To frame the shots even better, the remote can be used to control the pitch and roll of the camera. In most cases only the pitch axis is of interest to tilt the camera down or up. You can either use the same remote and receiver that you use to control your drone, or more interestingly you can hook it up to a secondary system that is controlled by the camera man.

The sensitivity and the mode (absolute or proportional) of the RC input can be configured using the GUI.


Ports

A1 is for pitch axis  (tilt camera up or down)
A2 is for roll axis

Pin Assignment

Bottom pin is ground (out-most on the board)
Middle pin is 5V
Top pin is signal

Step 14: First Flight

First test of stabilization. Ignore the blotchiness, we're using my old GoPro with the super-scratched up lens for the first couple of tests. Once we've got a reasonable lens cover we'll make an pretty video ;)

But this should give you a good idea of what the gimbal does. Each time the quad moved side to side or foward/backward, the quad itself is tilted quite a bit. But the BLG corrects for that and the footage gets a much more "floating" look than if the camera was mounted fixed.

At 1:35 you can see the pitch/tilt down using the remote. At 2:30 you can see how the gimbal resets to level. The motion is very slow and smooth. With the GUI this can be speed up and the max angle can be modified.


Comments

author
chubby8 (author)2016-03-11

I odererd this of ebay for £30, arrived in a couple days built, with frame, motors, gyro/ accelerometer sensor and controller board

received_976301165750602.jpeg
author
BradBuilds (author)2015-10-14

"Note that since this is a three-phase motor, the order of the wires doesn't matter." Is that really true? My old gimbal motor got the wires pulled put, so I can just solder them on in any order right?

author
dronelifestyle (author)2015-07-05

Great read! Just referenced this resource on our 'Tips for Better Drone Photography' article here: http://dronelifestyle.com/expert-tips-drone-photography/

author
gbeltrao (author)2015-06-27

Great instructable! So, where's the link to purchase the gimbal? It comes with everything together (frame, motors, controller, etc.) or gotta buy them separately?

author
stansell (author)2013-06-09

When you bought this, did the circuit board come with it? Or is that a separate piece that you bought?

author
oesti (author)stansell2013-06-10

The controller and the gimbal are two separate items from rctimer. Please note that there are many different choices of vendors. Also people have used controllers from different sources with this gimbal. But rctimer was the cheapest and only ready-to-ship product at the time I ordered.

Gimbal

http://www.rctimer.com/index.php?gOo=goods_details.dwt&goodsid=872&productname=

Controller

http://www.rctimer.com/index.php?gOo=goods_details.dwt&goodsid=884&productname=


author
gbeltrao (author)oesti2015-06-27

Both links are incomplete... dead.

author
annawhite0205 (author)2015-05-31

It is a nice blog about brushless gimbal drone designing. Some new features can also add in these stabilizer for making it much more attractive. To enhance the quality of camera 3-axis gimbal seems effective. You can checkout following website for some ideas for drone

http://kumbacam.com/gimbals/kumbacam-3-axis-smartphone-stabilizer

author
-max- (author)2015-02-18

Are the brushless motors geared down? How do motors which are supposed to rotate fast and inaccurately have the ability to precisely control angle like that? Especially having to overcome magnetic cogging? Is there a small gearbox similar to that inside a servo which allow slower, more precise control for the feedback loop from the accelerometer sensor thing taped at the bottom?

author
mushroom glue (author)-max-2015-05-23

They're not geared; the accuracy is down to feedback. The motors are able to move relatively slowly and smoothly if given the apropriate signals; I belive that most motor controllers hard-switch the signals to the motors, wheras the signals generated by gimbal signals are far smoother, generating a good aproximation of a sine wave (if continuous rotation is required). The lack of brushes etc. allows for this smoother control. The feedback from the accelerometer generates the precision in the system.

The reason the motors are not geared it because the gimbal needs to be able to react fast, which is something ungeared BLDC motors are good at. Outrunners like those shown are also pretty torquey, which helps too.

author
d.martinfree (author)2015-04-10

what is the relationship between eh rctimer and the arduino? I don't see any instructions to put this all together as far as the pins and the arduino and the rctimer relationship.. Sorry for the noob question.

author
ukionz (author)2013-06-09

Noob here, sorry for stupid question. Is the controller board accept signals from receiver so we can change angle (tilt) when flying?
Thanks in advance.

regards
Yu Kion

author
oesti (author)ukionz2013-06-10

Yes you can! I added the instructions of how to do that as step 13 of the instructable.

Ports

A1 is for pitch axis (tilt camera up or down)
A2 is for roll axis

Pin Assignment

Bottom pin is ground (out-most on the board)
Middle pin is 5V
Top pin is signal

P1030333.JPG
author
BrysonHicks (author)oesti2014-03-23

Just started getting into RC so this is a noob question.

The rc transmitter has a ton of switches and dials. How do you choose the one to control the gimbal? Would it have to be a dial instead of a switch?

Im looking at this one: http://www.hobbyking.com/hobbyking/store/__8992__T...
Could you control it with the dials on top? I assume the transmitter labels what dials go with each set up pins on the reiceiver, then you would just plug the A1 port into the correct pins on the recicever. Right?

author
Squidyman (author)BrysonHicks2014-06-05

Usually one would use a head tracker. That connects to the trainer port on the back of your radio. Hobbyking has some affordable head trackers (~$50) :D

author
ryugatana (author)2014-04-07

I'm a little confused about powering the board. Do I just hook up my copters 3s (~12V) Lipo battery straight to the leads on the board? Does the input voltage matter as long as it's up around 11-12V? Thanks in advance.

author
Squidyman (author)ryugatana2014-06-05

Yup, it can handle the voltage. I believe it is 2-6 lipo support.

author
maninvan (author)2013-07-27

Thanks this is a great tutorial. Though I found it after I had put the gimbal together. The biggest problem I had was connecting the board to the motors. I disagree that the order of the wires soldered to the motor doesn't matter. (it doesn't matter is regards to not breaking anything if the wrong order) We spent a long frustrating time connecting the motors, sensors to the correct ports and with proper orientations. If you could include a diagram that showed exactly the order to solder the cable to the motors. Which default orientation to connect to the gimbal motor outs, and which motor out is which (pitch, roll). It would make the process a lot clearer. You can change the motor assignments, in the software, but people really want as plug-n-go solution as possible.

I will give you top marks for the 'gotcha' not working mistakes as that helped a lot.

I have to say, that just for a couple of markings on the setup from RcTimer and diagrams on the Brushless Gimbal site, I could have saved a few hours for other things!

PS: Remember to balance the Camera first in the gimbal ;-)

author
remcogr (author)maninvan2013-10-28

Replying to you directly, maninvan, hoping that you can help me with powering my gimbal. I feel like a newby, but I cannot find where to power the gimbal. I want to connect a 3S 11.1 v 1800 mAh lipo, but cannot find where to connect the power cables. I see an USB connector (but that is for testing and balancing, right?), some pins saying 5V and GND (but 5V is too little for powering the gimbal, right?) and a + and - pins. I tried that, but that doesn't work.Please help. THNX

author
maninvan (author)remcogr2013-10-28

see http://code.google.com/p/brushless-gimbal/wiki/martinezcontroller if you are using the martinez controller. Is the connection that say AKKU 3S meaning LiPo 3S (don't connect the wrong way!)

author
remcogr (author)2013-10-28

Thnx very much for the instructions. I feel like a newby, but I cannot find where to power the gimbal. I want to connect a 3S 11.1 v 1800 mAh lipo, but cannot find where to connect the power cables. I see an USB connector (but that is for testing and balancing, right?), some pins saying 5V and GND (but 5V is too little for powering the gimbal, right?) and a + and - pins. I tried that, but that doesn't work.Please help. THNX

author
fanman7 (author)2013-07-26

Great Instructable. If someone wanted to ramp up the size of this to handle a payload of around 5 pounds for say a DSLR. Would these BLGs be enough or would you need larger ones? Where can these be found besides RCTimer.com ? I'm thinking of making my own, since the ones being sold out there are crazy expensive.

author
TravisNeedham (author)2013-07-17

Can someone tell me how much power the control board takes, and how I am supposed to know? I can't find it on/in a manual anywhere.

author
oesti (author)TravisNeedham2013-07-17

I'm running it off a 3S 500mAh battery. I don't have a number for you but it seems to consume very little. Of course that all depends on the BLG motors and now much work they have to do.

author
oesti (author)2013-07-12

I just upgraded to Brugi 0.49 r161 and had a much better experience than with r77 . This version pretty much works out of the box. I only had to increase the RC min & max angles (to tilt more than 30 degrees) and reduce the RC low pass to 1 second to make the movement faster.

author
rvyas (author)2013-06-11

Oesti, Is there no cheaper way to make it? like if I buy cheap 5010 motor from rctimer and rewind it? is rewinding easy are recommended? Have you been through that?
and can I use wood and cheap acrylic to build the gimbal?
Please help me.
Also can I use open source gimbal board thats available for 40$..?

author
oesti (author)rvyas2013-06-12

There is no doubt that you can make a gimbal from the mentioned materials. The required bearings and the attachment to the motor shaft make it a bit more daunting than other DIY
projects.

Rewinding motors seems to be a very intensive task. I have never tried it but I could see myself breaking the motor in the process. The good news is that you can buy ready made BLG motors for not much more:

http://www.rctimer.com/index.php?gOo=goods_details.dwt&goodsid=871&productname=

author
thegooberman (author)2013-06-07

It says "using rewound brushless motors" can you buy the motors rewound or do you have to rewind them yourself. If you have to rewind them yourself, are you going to include that in the part 2 of this tutorial?

author
oesti (author)thegooberman2013-06-08

A few months ago re-winding yourself was the only option. Now there are several suppliers which carry motors specifically would for BLGs. The RCtimer gimbal used in this instructable comes with two BLG motors. Below is a link to a re-winding tutorial, it's seemed very daunting to me.

http://www.rcgroups.com/forums/showthread.php?t=1823636

author
naeger (author)oesti2013-06-09

The link you gave explains HOW to rewind a motor but not WHY ....

I am new to this. What is this whole "rewinding" about? Why do you have to rewind the motors or buy specially rewound motors in the first place? Why can't you just buy ordinary brushless motors for the gimbals?

author
oesti (author)naeger2013-06-09

Let me google that for you ;)

This thread has a lot of good information about re-winding:

http://www.fpvhub.com/index.php?topic=11021.0

This sums up the purpose of re-winding pretty well:

"The winding are of thinner wire with more turns for a higher resistance which gives more torque for less current in the range required for the gimbal operation"

author
lagri (author)2013-06-09

Thanks for the link, oesti.
it´s incredible... wow, it´s better than the passive steadycams solutions.
I tried to find through Google, motorized steadycams systems, but no luck.

author
billbillt (author)2013-06-09

great!

author
ducktape100 (author)2013-06-08

very cool

author
lagri (author)2013-06-08

Would it be possible to do the same for other larger cameras?
2,5 kg or more?

author
oesti (author)lagri2013-06-08

Yes it seems like the concept can be scaled up. There are some commercial products start to make an appearance:

http://diydrones.com/profiles/blogs/3-axis-brushless-gimbal-system-steadicam-for-pro-users-arducopter

author
mhkabir (author)2013-06-08

You got all the stuff in the package? Mine was missing the countersunk screws :(

author
oesti (author)mhkabir2013-06-08

My set was only missing only screw and three parts that needed corrective action. This seems to be the disadvantage of ordering from China. But for the price, a certain amount of tinkering is acceptable to me. Hope you found matching screws.