ForfraBagfra

Let's Make Robots Robots
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Update: Just a small new video, nothing really. Just my studies, I use the platform for different testing of stuff. Video and slow motion helps :)

While playing around with stuff to use on another project, the 360Bot, I found some old RC cars. What people throw out, you wont believe it :)

Since I have 360 degrees view on the 360Bot (using a stepper motor), I thought it would be fun to make something that is the same both ways, and steers by "breaking" at the very center.

So I took two motors and put one at each end, so it is actually two rears facing each other. Hence the name, it is Danish, meaning something like "front to back".

The steering is done by a servo right in the middle: Loced on one side, twisting the other.

I hooked it up with my Joystick / Easy Radio, and I had a remote car to test, before I perhaps add sensors and 360 view. However, I doubt that it will go any further.. But it was fun, so I thought I'd share it with you :)

Testing what one can do with 4W differential drive, and steering by .. erh..

  • Actuators / output devices: 2 RC cars gearboxes
  • Control method: Easy Radio wireless
  • CPU: picaxe 18x
  • Power source: 7.2V Tamiya-style racing pack
  • Programming language: Picaxe basic
  • Target environment: anywhere
This is a companion discussion topic for the original entry at https://community.robotshop.com/robots/show/forfrabagfra
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Very nice! thats a pretty

Very nice! thats a pretty fast one man:) Love the name btw. And trust me, some people need to be a bit more on the creative side before they declare something trash:) sweet bot fritsl!

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That’s a great idea. I was

That’s a great idea. I was sorta’ thinking about my next 'bot having tank treads, but now I’m reconsidering.

I really like the concept of a “twist in the middle” robot. I’ve always been interested in the way the huge construction loaders twist in the middle to steer.

I’ll have to start looking for the right hardware to do this. In my mind, it seems like it’d HAVE to have differntial axles. Hmm… that may be hard to find.

Thanks,

Duane S

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Nah
Hack up any Tamiya-style R/C car for a REALLY powerful motor, gearbox and diff. Another possibility would be to try it with only one wheel powered. Of course it will have a tendancy to go to one side, but those R/C cars are expensive to be hacking up…!

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this is a very nice

this is a very nice one!!! i love the way it moves!!

What kind of servos do you use? they really fast!!

Could you please explain how are you powering the system? Or, if possible post some (newbie) schematics ?
i´m looking forward to power a system with a Nickel 9.6V batt, 2000 mAh but i am a bit afraid of burning out things…

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There is only one servo, the

There is only one servo, the one in the middle, and as you can read above, it is just a plain servo. Cheap.

Schematics… I dont know electronics, so no, sorry.

It is a Polulu motor driver-board (I think - any would do), and the Picaxe servo controller board that has a chip on it dedicated to control servos. I use this because it is also radio controlled with an Easy Radion module, and the picaxe cannot both wait for serial in and control the servo - so I let the picaxe send messages to the servo controller and the motor driver, and the rest of the time it is waiting for serial in from the easy radio…

The motors are, as you can read, 2 rear ends from 2 different remote controlled cars.

I have added sensors to it now, it is what I call "assisted drive", that is it is remote controlled, but the sensors are on, and if I am too close, it steers around, reverses out of trouble etc.

I think what you want to discover here is the little board dedicated to control / power 2 motors. It also has 5V out, so the battery (7,2V Racing Pack) goes to that, and the motherboard is powered from that.

This is not the one I use, but it is something like this: https://www.robotshop.com/letsmakerobots/node/678 (this one is serial controlled, mine is on/off of 4 pins, and this does not have 5V out as mine… I will find out which one I am using if it matters to you :slight_smile:

 

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You can see it here, it is

You can see it here, it is the red board in the middle:

https://www.robotshop.com/letsmakerobots/files/field_primary_image/IMG_4839.JPG

 

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"I think what you want to

"I think what you want to discover here is the little board dedicated to control / power 2 motors. It also has 5V out, so the battery (7,2V Racing Pack) goes to that, and the motherboard is powered from that."

What i really want to know is, do you connect the battery directly to the motor control board?

I´m starting to like the PIC stuff :slight_smile:

Thank you once more fritsl!

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7.2V Battery to motor
7.2V Battery to motor control board. Motor control board sends 5V to Picaxe board. Picaxe board sends signals to motor control board. Motor control board sends 7.2V power to motors.

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clear enough!! thnks :slight_smile:
clear enough!! thnks :slight_smile:

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Motor driver…
It look’s like a Solabotics L298 compact motor driver kit.

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Solarbotics - thas’s

Solarbotics - thas’s it!

http://www.solarbotics.com/products/k_cmd/

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you give so much

you give so much information,and thats a good thing

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Hi Frits,Is the slow motion

Hi Frits,
Is the slow motion video a product of the camera or post editing?

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Post editing. I REALLY would
Post editing. I REALLY would like a high speed camera!!