Instructables

Starting with robotics (Arduino)

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Picture of Starting with robotics (Arduino)

Starting with robotics can be hard, if you don’t know where and how to start. Best way to start is to make mobile robot. In this step-by-step we will show you, how to make cheap robot with parts available in your local store and household.

Before you start you should make some plans how platform should look like. We did some sketches how robot should look like. Later we made some modifications so everything fit in properly.

I made this robot with my good friend purgec. (http://www.instructables.com/member/purgec/ )
 
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Step 1: Tools and parts

Picture of Tools and parts
Parts:
- board
- breadboard
- arduino (any one you like, we used mega)
- motors
- fasteners
- Velcro fasteners (hook-and-loop)
Tools:
- screws (for making holes in board)
- knife
- tape

Step 2: Markup

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You should start with marking up where everything should be. We did realized, that breadboard is little to big so we modified sketches to fit breadboard on base. Because of that motors must be mounted little bit back then in sketch.

Step 3: Breadboard

Picture of Breadboard
We mounted breadboard with Velcro fasteners. This step is one off the easiest. We used fasteners with glue on back side. We just have to cut them down and stick it to base board and breadboard.
In late steps we realized, that we did that too early because fasteners can got messy from making holes.

Step 4: Motors

Picture of Motors
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We used modified hobby servo motors. How to modify a servo: http://www.instructables.com/id/How-to-modify-a-servo-motor-for-continuous-rotatio/
For mounting servo motors we cut holes in base board. After debate how to do it (drill can destroy this kind of board) we cut holes with two screws, smaller and sharper for making holes and bigger to make holes bigger.
For mounting motors in position we used fasteners. Fasteners were cheap, but where to short so we improvise. After this step robot was nearly finished.

How holes were drilled: (video comming soon)
amiller727 months ago
I'm actually pretty new to the electronics field and to arduino so excuse my lack of knowledge lol but here's what I have so far
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vonPongrac (author)  amiller727 months ago
Those white motors are DC motors with reductor. Those can bedriven with H-Bridge (Arduino Motor Shield). You can also make your own H-Bridge with transistors or integrated circuits, like L293D. For those motors you should use 7 V supply. These motors are from RC car?

That green board, what is it?

I do belive that your 3 batterie pack will not do the job. Arduino got 5 V voltage stabilizer on board. Stabilizer must have 7-12 V for propper action (4 AA batteries will barely do the job). Also, that black box, looks like there is battery inside. What voltage output does it have?

Sory about my last post... It was written in hury and it is a mess.
amiller727 months ago
I have some servos but I tore apart a rc car for its motors and reciever setup and as you can see I'm not currently implementing the arduino but would like to understand how I could also diagrams help me alot lol
amiller727 months ago
How would I do this without the motor shield?
vonPongrac (author)  amiller727 months ago
Remove mechanical blockadge from servo and instead of potentiometer use voltage divider made from 2k2 resistors (like in this ible). Then you just drive servos like regular servos, where value '0' is one direction and valuve '18' is another.
Your design is really simple and nice. However, you might want to put some friction for the wheels for its mobility. Just like a rubber ring of some sort that will fit your wheels.
vonPongrac (author)  arduinodude111 year ago
I cut down rubber gloves for that purpose. The diameter of gloves is just right to make tight fit with the wheels. You can see that from pictures.
I see, I wasn't able to notice at first glance. Thank you sir! That actually gave me an idea for my wheels :)
qquuiinn1 year ago
is that a motor shield? I dont think you need a separate shield just to control servos
vonPongrac (author)  qquuiinn1 year ago
Those servos are modified to constant rotation. there is no electronics or any potentiometer in there. Is basically a DC motor with reductor. To drive DC motor you should use H-bridge (motor shield). If I use digital servos that can rotate constlantly (like the one in LEGO Mindstorm nxt) there will be no need for any H-bridge.
Converting standard RC servos to constant rotation is fairly simple.. requires (a) removal of the position potentiometer, (these are usually 5K is value), and replacing them with a pair of 3.3K (red-red-red) resistors in a "M" (the two resistors in series, with the open ends where the outer ends of the POT were, and the center connection where the wiper was) and (b) filing-down the stop point on the final drive gear.).. Using the arduino servo library, you simply assign 90 as dead stop, and 0 to 89 as one direction, 91 to 180 as the other direction. This way, you only need a 5V supply (OTHER THAN THE +5V from the Arduino! the 5v regulator will not handle it!) for the red wires of the servos, and only needing the signal from the arduino, no H bridge needed. There are plenty of plans for modifying servos here on instructables too.
vonPongrac (author)  Gelfling61 year ago
I heard of that, but never used it. I like my way and it never failed me.
My modification got pros and cons. Cons is using H-bridge (more elements, not very cheap). Pros are that you can connect motor to any voltage up to 12 V (9 V for micro servo, I tested those voltages) and you can control motor speed with PWM.
So in the end modification depends on aplication in which motor will be used. You can check on my instructable LISA. I am using modified servos at 7.2 V for higher tourqe and H-bridge build with relays. But tourqe is still a little low. In future I plan to raise voltage up to 12 V. There is no way this can be done by your modification. But with Arduino platform it would be better to use your modification, becouse you get lost of H-bridge which is not cheap and you get the same result.
vonPongrac (author)  vonPongrac1 year ago
And I do realize that with your modification you can still use servo as servo, with my modification servo become DC motor with reductor.
... and yes, I do realize 2x 3.3K resisters do not add-up to 5K.. negligible extra 1.6K.. you're only reading a center value from the +5 to GND.. (2.5V)..
s005001 year ago
Have a look at my Project =D

http://lbsfilm.tk/arduino-amphibious-vehicle-test-platform-for-all-kinds-of-new-features/
charels881 year ago
That looks almost like my robot Sid, zip-tied continuous rotation servos but no electrical tape holding everything else down. Good Job!
PavelZP1 year ago
Веду свой блог про создание сайта.
deqwer1 year ago
any video for this robot?
vonPongrac (author)  deqwer1 year ago
In step Test is link to video.
eddevine1 year ago
Excellent , thank you this will be a project that I can't wait to start
vonPongrac (author)  eddevine1 year ago
Good luck with your project! Keep me posted.