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Old May 29, 2012, 03:19 AM
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FPV Tonka build log (not a Summit)

Inspired by the huge FPV Tonka Summit thread here on RCgroups, I also started to build an FPV Tonka. The most of you guys are using a Traxxas Summit for this, because it is an excellent crawler. But I donít have a Summit, and I found it too expensive to buy one for this project. So Iím building a Tonka on another model then the Summit, and thatís why I started this new thread. To show other interested guys (those how also want to start an FPV car project) that it is also possible with another RC car.
I know that the Summit have some nice features, like it is waterproof, remote locking the differentials and remote changing the high-low transmission. Those are options that will be not available on my FPV car. But I think that I donít really need those options for FPV.

I donít have an electric RC car, only a 1:10 nitro MonsterTruck. But I didnít want to build the Tonka on a nitro car, because it generates too much sound/noise. So I bought an electric 1:10 car. (Reely Detonator) And I have an Align Trex 450 and a Gaui 500x Multicopter. Both uses 2200Mah 3S lipoís, and I donít have any 2S lipoís. I wanted to use my 3S lipoís also for this FPV car. Iím going to connect them parallel, so I will get about 4400mah. But for that, I bought a motor and ESC that can run on 3S. (Turnigy TrackStar 100A Car ESC and Turnigy TrackStar 17.5T 1870KV)
I guess that this setup (on a 3S lipo) will be less efficient then a 2S lipo setup. But if I think that I can have a normal runtime with this setup.

I bought a 1mm aluminum plate. This material is simple to bend, and created holes in it. But when bending this with some supported folds, it really can be a strong structure. With this material I created some mount points on the RC car.


By the Tonka car, I removed the bottom plate. Created some holes in the Tonka frame. The Tonka body is really a nice fit!!
When I put the Tonka body on the RC car, the RC car gets really low to the ground. The suspension of the car werenít able to carry that weight.


But fortunately by this RC car, I can add some shocks. So I added four shocks to the RC car. Putted on the rear shocks a little bit stiffer springs. And then he can carry that weight really well!! The current weight of the Tonka and the RC car (without GoPro) is about 5kg now.


I also put a servo on the steering wheel of the Tonka. I used there a connecting screw (or sex bolt, I donít know the exact English translation), and put turned that with the thread side on the servo (with a little bit glue). And that was a really nice fit!

The next step is to build a pan/tilt system for the GoPro.
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Old May 29, 2012, 03:45 AM
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Nicely done! Tonka body looks like it is a perfect fit! Keep us updated on the progress
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Old May 30, 2012, 01:52 AM
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In the Spektrum DX6i I configured Dual Rate settings. For normal/slow driving I set D/R to 60% for the throttle (elevator). And put the steering (aileron) to 100%. So I don’t can drive at full speed, but have full servo movement for the steering. And in the other D/R mode (for fast driving). I set D/R for steering (aileron) to 65%, and the throttle (elevator) to 100%. So I can drive on full speed, but with reduced steering. With this method I can drive smooth on high speeds, and it can be handy when driving FPV.

I did take the Tonka for a ride. To test how it drives with the extra weight. And luckily it drives really nice! With this motor setup, he is really strong. And the Turnigy Trackstar 100A ESC is a nice device. It is configurable with punch control, so he will not make a wheelie when I go full throttle.
Only the internal BEC of the Turnigy Trackstar doesn’t work very well on a 3S lipo. My steering servo uses too much amperes. When I’m using more than 2amp, then the receiver stops responding. So I’m using an external BEC, to supply voltage to the servos. And with the external BEC, I don’t have any problems.
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Old May 30, 2012, 02:37 AM
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YR RIDE COLD BLOOD'D. you got me drool'n on this build. keep us posted w/details & pics.
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Old Jun 03, 2012, 05:06 AM
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I finished the mounts for the mirrors. Last week I ordered blind spot mirrors from internet, but they are a little bit oversized. Iím gonna use them for now. But I ordered on Ebay some smaller blind spot mirrors, so that it looks nicer by the Tonka. Until I receive the other mirrors, IĎm gonna use these mirrors temporality.
For the mounts I also used 1mm aluminum plate. And drilled a hole of 14mm in it, and that fits nicely around the Tonka top.
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Old Jun 03, 2012, 01:22 PM
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I copied the pan/tilt system from the idea of the Tonka from replayreb. I created a large aluminum base. With this I have a nice base to attach the pan/tilt system. For the pan system I used an HTX900 servo. And did the 180degrees mod with it (added two 2.2kΩ resistors on the pot meter), so it can move 180 degrees around. From aluminum I created a piece to attach the pan servo, so that the servo canít move around.


On the HTX900 servo I put a circle servo horn. On this horn I attached the aluminum pan mount. I will attach it with four screws to the aluminum mount. And the screw heads are sliding on a metal spacer, to get a stable pan mount point.


For the tilt system, I placed a servo on the back of the GoPro holder.


I had not many clearance for the GoPro camera. Because it hits almost the roof top. But eventually (after many measurement and also trial and error) I fitted the pan/tilt system under the roof top.

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Old Jun 03, 2012, 01:29 PM
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Below the rear bed I placed the RC receiver and the OSD board. On the rear bed I placed the video transmitter.
On the rear of the Tonka I created a small mount for the 433mhz antenna. A coaxial cable is connected from the antenna mount to the Rangelink receiver.


In the motor hood compartment i placed the 5A BEC, OSD gps module, OSD current sensor and two lipo's.


The components that I'm using are:
Rangelink UHF LRS
Tiny OSD 2
5A BEC
5.8Ghz 500mw Video transmitter
GoPro Hero 2

I'm almost ready, only need an 2.5mm jack plug for the live feed of the GoPro camera. And then I'm ready for some drive testing.
I'm curious what for distance i get with the 5.8ghz video transmitter. If it is too disappointed, then I’m gonna use a 1.3ghz video transmitter.
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Old Jun 03, 2012, 07:20 PM
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Coming along nicely! Looking forward to seeing your first video.
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Old Jun 05, 2012, 04:39 AM
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Roosendaal, Netherlands
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Pretty cool build! Im working on my own summit based tonka.

The gopro pan/tilt looks exceptionally nice, hope mine will work out like that, too.
Ill definitely use your pan section pictures as an example to make my own.
I want to do the tilt part slightly different though, I want the cam to sit back a little further then yours.
The implication would be the TV-out plug getting in the way of the armature, luckily ive got a CNC machine.
Im going to cut out a hook shaped arm so the armature "approaches" the cam from behind,
making the actual hinge out of some old motor ball bearing and an M3 bolt with some spacers.
To actuate it, ill use a ball link set from a helicopter. Zero play so hopefully zero shake.

One thing that caught my eye though, are you really going to mount your GPS receiver under the metal hood?
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Old Jun 06, 2012, 05:42 AM
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Quote:
Originally Posted by Freakazoid View Post
...
One thing that caught my eye though, are you really going to mount your GPS receiver under the metal hood?
YeahÖ youíre right. I placed the GPS receiver under the metal hood. I didnít have a change to try my setup now. I hope that he will receive some GPS satellites through the metal hood. If not, then I have to move the GPS module to the rear bed. But the idea was to get the GPS module far away of the RC receiver and the video transmitter, for any signal interference.

I hope that it doesnít rain this weekend. Then Iím gonna test my Tonka.
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Old Jun 10, 2012, 11:54 PM
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I did yesterday my first FPV outdoor test with the Tonka. It is really fun to do! With the test I got a 500mW 5.8 GHz video transmitter mounted on the rear bed (I know, the antenna should be higher. But I wanted to test the Tonka )
But the distance of the video signal was disappointing. Something around 250 meters in plain sight. And when an object was between the VTx and the RTx, then the signal was almost gone. So thatís why I soon gonna test a 1.3GHz video transmitter. So that hopefully the video uplink goes through some objects.

As I mentioned earlier, I configured Dual Rate settings on my Spektrum DX6i. Thatís working really fine! For normal driving the max speed is around 10km/p (sounds slow, but when driving FPV. Then it is really fast enough) And if I flip the Dual Rate switch, then I can drive max 20km/p with limited steering. The top speed is then 20km/p, I experience that's really fast when I drive FPV.

I'm using two 2200mAh 3S lipo's connected parallel to power everything in the Tonka. I ain't disappointed of the runtime of this setup. After 30 minutes driving, only 2000mAh was used. So I think that I can safely drive for around 45 to 60 minutes. Depends on surface and how fast I'm driving.

Here is the movie of my first outdoor FPV test drive:
2012-06-10 Tonka first FPV outdoor Test (5 min 27 sec)
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Old Jun 11, 2012, 02:13 PM
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After my first test run, I wasnít totally satisfied about the position of the camera. Because the visibility of Ken isnít really good in the movie. So thatís why I gonna change the position of the pan/tilt system a little bit backwards.

Iím also busy with a extra antenna mount for the 1.3GHz antenna. And so I keep working on this project.
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