Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: TennisBalls on July 19, 2011, 04:02:18 AM

Title: Automated/manual bluetootch control for webcam tracked mini rolling ball robot
Post by: TennisBalls on July 19, 2011, 04:02:18 AM
Hello everyone and thank you for the amazing community.
With your help I will try not only tosolve my problems, but to collect infomration that will make others and they will use this topic as some sort a tutorial.
Some of the questions I will ask, are probably already solved somewhere in the forum, but I still need somewhere to start from.

So what I will be asking and what info I need I will try to say in the following lines:

I decided to build a robot-ball.  I will try to use a tennis ball at all cost, and only if I cannot put all the electronics inside I will move to bigger ball.This is for cat toy or just for fun.
I would like to make a robot rolling ball bol using 2 micro (or mini) servos that will move the weight (center of gravity away from the geometrical center of the ball inside the ball itself and also will move the weight up "forward back sideways in the spherical part of the ball inside so that the ball will be able to move around on the floor in all directions.

FIRST LETS START WITH THE MECHANICS (something I thought about the basic mechanic design that will move the ball around.
SO we have 2 servos. I put them side bu side and I put "wheels"directly on the two servos. So that the weels are parallel.
You know how a tank moves around? by stopping or reversing the tracks on its side. Good. My idea is basically the same. I have 2 parralel motors, and by stopping or reversing one of them I will be able to move the ball around (but thats more the software type of thing I will leave for later)
So we have the 2 servos, now we need a OWER SOURCE-batter-I will probably use some kinda NiMH or LIION or LIPO cells from cellphone or something else. I will see what will be heavier-the battery or the 2 servos and will put in lower.

NOW THE POST PROBLEMATIC PART HAS COME: THE CONTROL.

How do I control the robot. I have 2 option. I forgot to mention that I am experienced modeller. I can immediately find some tiny 2.4 GHZ Rx (receiver) that is used to control ordinary models. But it will be hard to controll it from the PC.
SO lets see if there is CHEAPER and also easier option.
BLUETOOTH> ok sound easy but I have no idea how to make it.
I know I need bluetooth on the PC side- ok good. I will buy a cheap USB dongle for 1 or 2 US dollars and there we go.
I am not asking all those questions before i spent hours reading
I know that I need some sort a bluetooth module on the "ball"side that will control the servos.
So here comes the ëpic"question. can I use cheap USB bluetooth dongle to connect the tennis ball robot to my PC bluetooh, and then use some kind a servo controller (PWM encoder or something) that will decode signals from bluetooth dongle in the tennis ball and drive the servos?

Or I have to use some special ready made or half-ready made bluetooth transceiver in the ball?


OK enough with the bluetooth control from PC. MOre softare questions and others will be talked over later.

THe third "part"of the topic (I already searched info for that too) is to control the ball by TRACKING it with the most ismple and cheap option available- a WebCam!
I already found some info on the net about ready amde sfotware such as roborealm. (I cannot afford to pay such high price for that software, but when I am rady to use it I will use 30 day trial)

So the BASIC IDEA
make a tennis ball robot with bluetooth receiver. Computer tracks tennis ball with webcam, and then moves it around the room eventualy around obstacles and cat/baby or other pet plays with it.

I suggest that we start the discussion with the bluetooth thingies, since I am still trying to figure it how can I control the robot from PC....

And again-I would like to thank all of you who will take part in this discussion and lets keep the topic clean so that only useful posts and info is visible.  :)
Title: Re: Automated/manual bluetootch control for webcam tracked mini rolling ball robot
Post by: TennisBalls on July 19, 2011, 04:06:15 AM
I forgot to tell you that I am currently reading some of the must read tutorials for beginners :)