Building a PC-based robot

[Olsson]

Hello!

First of i better introduce myself. My name is Christian, I'm eighteen and live in Sweden... Um so you understand why my English isn't that great.. ;) Amway just got the two latest Robot issues and I'm about to make a PC-based robot much like the articles in the mag. So I'm wondering if there are other ppl here who have done a PC-based robot?

I'm going to have pretty much hardware (sensors, tilt-camera, Wi-fi, bluetooth and much more) I like my robot to be capable of doing many different things. It might weight a bit so good motors and batteries will be necessary. Any idea of what parts I should use? The ones used in the botmag articles seems fine but if I could use anything better or more powerful that would of course be it as long as the prize isn't too high.

[Kevin Berry]

Christian, welcome. I am NOT the guy to help you, but I get credit for saying "thanks for posting" first.

I'm sure the REAL roboteers will jump in soon.

Kevin

[Olsson]

Thanks Kevin :)

[wrighthobbies]

Christain,
There is a lot of information on using PCs for robotics. Laptops and mini-ITX systems are commonly used. One thing you will find is that a lot of people building PC based robots also use microcontrollers to help manage the I/O. The data from sensors and control output can be a challenge to manage directly from a PC. By putting a microcontroller in the middle, you can use a serial port to interface to the PC and delegate tasks to the microcontroller.

You should also take a look at www.trossenrobotics.com. They have a whole system for PC-based robotics plus just about everything else you may need.

Good luck with your project!

[wrighthobbies]

Here is an example of a PC based robot that has lots of sensors and uses microcontrollers to help pull it all together.

http://robotics.ee.calpoly.edu/dokuwiki/doku.php?id=spybot:start

Inside the bot, you can see a pair of DevBoard-M32s that CalPoly used. The microcontrollers talked to each other and the PC using I2C.

http://robotics.ee.calpoly.edu/dokuwiki/lib/exe/fetch.php?media=spybot:microcontrollers.jpg

[Olsson]

Thanks wrighthobbies, that was very helpful. :D

I have done a lot of thinking and reading on that trossen robotic shop and in my Robot magazines. But I'm not sure exactly what hardware I'm going to use. I thought about using the exact same motors and servos as the one used by Matt and Peter in the PC based Robots article in Robot issue 4 and 5, just to avoid eventually problems and.. they are kinda cheap too! So what do you think? Bet i can get a lot of help from the experienced roboteers here on the forums and I don't think i can manage without it! :D So.. this is going to be a big project for me and the robot are going to be pretty heavy i think (with all the hardware I want for it) so any comment on the hardware? I don't want to buy something that doesn't work in the long run. Any more help would be awesome!;)

The hardware that i might be using:

4-Servo Phidget USB Servo Controller -$67.50
http://www.trossenrobotics.com/store/p/3188-Servo-4-Motor-Controller.aspx

AC wall adapter 6V Power Supply - $14.40
http://www.trossenrobotics.com/store/p/3442-Power-Supply-USA.aspx

BaneBots 45A Peak Motor Controller - $57.00$ x 2
http://www.trossenrobotics.com/store/p/4267-BaneBots-Motor-Controller-45A-peak-.aspx

25:1, 36mm Planetary Gearmotor, RS-545 Motor - $38.95 x4
No Load RPM: 624 rpm
http://www.trossenrobotics.com/store/p/4238-25-1-36mm-Planetary-Gearmotor-RS-545-Motor.aspx

(Not sure about batteries.. In the first article the Gel Cell Zeus was used but with only 7.2AH. In the later article a Werker with 12 Ah was used, almost like the one below i think.)

Hoveround 12 volt 12 Ah SLA Battery - $35.95 x 3
http://www.lowcostbatteries.com/Scooter-Batteries/Hoveround/12volt-12Ah_p/12volt-12ah.htm

or..

Gel Cell (12V 7.2AH) Zeus - $18.00 x 3
http://www.trossenrobotics.com/store/p/3448-Gel-Cell-12V-7-2AH-Zeus.aspx

More things will eventually be needed. But that's it for know.
Anyway.. I do have a couple of questions, so i list them so that they can be more easily answered. (It's mostly about the upper mentioned hardware.)

1. So i might use three batteries, one for the electronics, one for the PC and one more for lights and other accessories. What do you think? Any suggestion about some other lead-acid batteries that might be better to use?

2. The robot will weight, do you think four RS-545 Motor with 624 rpm no load will handle that in a good speed? I would love to use even better and faster motors as they don't seem to cost too much more really. :D And what about the sound, will they sound very loud?

3. For good steering in for example small places, would four or three wheels be better too choose? Like two wheels with motors and one behind in the middle so that the robot could spin instead of steering like a car. Not sure on this though.. Four wheels would of course handle more weight.

I think that will do for now.. Hope at least something can be answered. It's not that I'm compete new new to all this, but almost so it would be great if someone with experience could help a little bit. Thanks!

[HakBot]

I built an interface that allows you to connect your r/c radio to a PC. It will allow you to control your r/c vehicle from the PC. www.endurance-rc.com/pctx.html

A lot of my projects use a camera and do vision processing on a remote pc.

[Kevin Berry]

Having said I'm not the guy to help you, here I go anyway :-)

I think you have WAY overestimated the amount of battery you need. Those Banebots pull 0.8A unloaded, so even under a medium(ish) load you're looking at maybe 2A x 4, so you've got 4 or 5 hours of run time. Unless you really need that you could go with just one and recharge every hour or so. Not sure what a PC draws, IIRC its like 150 watts or so.

I like SLA's for first bots, they are inexpensive and easy and chargers are cheap. If you really get into a weight issue, and have the money, you can move immediately to NiMH or Li-Poly and be state of the art. But it does cost a bit!

Except in combat applications, or life threatening situations, I don't see a need to have seperate batteries for different functions.

[TheDuck]

If you are staying connected to the computer you might even draw off the 5V (up to around 500mA) of USB power until you figure out exactly what your power needs are. However, the thing would be light as a feather at that point giving you a false sense of security on your weight calculations. Still, if you expect to be over-engineering your motors and momentum doesn't become a significant factor it might do until you are more comfortable with your power source.

[leynyabejo]

hi before anything else i like to intoduce my self... im leyny 17 years old from philippines taking up the course of computer engineering. now im third year college he.... our thesis is all abput robotics so that i searching about robotics... and im not good in doing some program.... ohm... by the way i lyk to share my topic to all of robots that accept any command... i want to know whta materials i need and please sent me some tips to do some programs i need to work my project....
thank you and god bless to all of you......:) :)

[HarryBotter]

It would likely be best to just start looking for information with Google. Why not start with a search on "robot materials" and see where that takes you?

If you then have any specific questions perhaps someone on the forum may be able to help.

Harry

[airman00]

Goto my blog http://erobots.blogspot.com
It has all the info.

[airman00]

Goto my blog http://erobots.blogspot.com
It has all the info.

[D0n]

I pulled the joystick apart on my wheelchair controller, and rigged it up with a couple servos to obtain rc control with the stock (everest and jennings) controller. happy to offer help on that if that's where you want to go.

....next step is using phigits kit for sensors and automation. I'll be connecting those to a macbook and operating from an imac desktop......