This instructable will be about building an FPV car that got the following functions:

3axis gimbal stabilized camera
5.8GHz FPV live video
NAZA M v2 powered

http://youtu.be/y6GRpKTVfhk

On the video you can see how the Zenmuse gimbal is turning outwards in turns. That's because the NAZA controller does not getting any signals from the Rx. That makes it "think" that the quadcopter gets turned by chance.

See The NAZA chapter for a walkaround.

Step 1: THE CAR ITSELF

The car itself is a Team C TC02 EVO 2WD competition buggy.

I decided for this chassis, as i liked the idea of the angled front suspension of 2WD buggys, and they got a lot of room in the chassis because of the back-mounted motor.

It uses two sets of front tires to eliminate all forms of shake due to tire vibration.

Motorwise it uses a 540 class Tamyia motor i got from an f201 kit, and a standard ESC.

All devices are powered in parallel by a 4 cell LiPo battery.

I use small o-rings on all suspension links to make them virtually free of any tolerance.

The wooden part to mount the Zenmuse gimbal i is strapped to the rear shocks-dome and is cut 45° to make room for the z axis motor of the gimbal.

Step 2: THE GIMBAL

I use the Zenmuse H3-3D gimbal, that has a lot of functions that make it nice for FPV

an FPV mode, that means that the camera starts to follow every turn in a 30° range
it powers and feeds the video from the GoPro so you have no cables at all
as you have to use it with a NAZA you can use the rudder signal to turn the gimbal

In the FPV mode, it stays stabilzed until you reach a 30° angle from the original position. After that it follows the motion, which makes sense.

It uses a software to setup, that runs on OSX.

Step 3: NAZA-M V2

NAZA M is a flight controller for quadcopter (up to octacopter) that can follow GPS waypoints.

It get's the four channels of the Rx and converts the signals into four ESC signals for the four motors of the quadcopter. During that conversion it adds and subtracts a lot of information to counteract to unwanted movements of your aircraft. While doing that it assumes that the controller sits in an aircraft that can tilt and turn around its own axis in a three dimensional room.

Obviously things run a bit different in a car.

Besides beeing in a 2 dimensional room (the street) instead of a 3 dimensional, a car has certain mechanics of motion while turning, with a dedicated radius, depending on the angle of the wheels.

The good news is, that the NAZA controller runs standalone, without the need of any startup or other servo signals to run properly. It's even better then that: the NAZA controller advances some of the rudder signal to the Zenmuse gimbal, which means the gimbal turns "into" the turn instead of trying to counteract and turning outwards in turns.

I made split servo cable, that feeds the NAZA rudder input and the steering servo of the car.

The NAZA controller comes with a GPS unit that's best mounted away from any motors.

I strapped all DJI boxes together and placed then on the only level surface the car has.

DJI says to make sure they get enough air to stay cool, so far they stayed cool even when strapped together.

Step 4: FPV VIDEO

I used an ImmersionRC 5.8GHz 25MW Rx/Tx combination.
Setup is pretty easy.

It comes with all wires, already soldered to their connectors, with one end open to solder them into your setup.

As the Zenmuse gimbal also comes with a set of pre soldered wires, it's easy to connect.
Just shorten the cables as you like, and connect/solder the video and mass lines together.

Step 5: REVIEW MIRROR

The review mirror is made of a small plastic mirror i found in an LED solar-lamp.

It's looking cool, but the size of it, plus the resolution of the FVP video, makes it a gimmik though.

Step 6: GPS WAYPOINTS

Will be another Instructable.

With an arduino, it's no problem to convert the ESC signals that the controller outputs into a LEFT/RIGHT steering servo signal and a FRWD/RWSE servo signal for the ESC of the car.

The problems could occur when the controller wants to bank the quadcopter to the left for example and the car doesn't because banking to the left is re-mapped to servo left.

All it does is it just steers to the left and without any forward motion, nothing will happen.

That could confuse the controller.