Building a robot! (wireless)

[Sir Fredrick]

I'm working on a proposal for my senior project (as an undergrad)...I want to build a robot.
I'll probably be coming here with lots of questions, but for now I just need suggestions on the following:
Hardware to allow a PC to communicate with a robot remotely. The range doesn't have to be spectacular, the robot will be in the same room at the PC.
It should be easy to interface with this hardware in a windows 2000 or windows xp environment.
It should not be outrageously expensive.

Any suggestions?

 

[singh]

I was thinking about building a robot a while ago and after doing some research, the best idead I had was to have a cheap laptop onboard the robot. Then the communcation can be done using Wi-Fi. The laptop can be real cheap - like a Pentium I or even a 486.

Here are some Robotics parts related links:

http://www.lynxmotion.com/
http://www.robotstore.com/

 

[Sir Fredrick]

The problem is that even a cheap laptop is pretty expensive. Plus it adds a lot of weight to the robot, and this is something that should be lightweight and small.

 

[Cogman]

You can get PDA's To Be wireless . Really, unless you are planning to program it, I dont think that A laptop is the way to go. You will need some programing skills for a project like this, And you will need access to a radio shake (sp?) to construct the parts. Come to think about it, A laptop might be easier, if you get a used one.

 

[Sir Fredrick]

I am very proficient in C++, so I'm not worried about the programming aspect of it.
If I have to use a PDA then I'll have to learn the proprietary interfaces, spend a couple hundred on the PDA and the wireless card...plus a wireless card for the PC that will control the robot.

Has anyone heard of something called wireless serial?
I'm not sure if that's the exact name, but I know that it connects to the serial port on a PC, and allows the PC to send signals to a robot with a receiver on it, as though the robot were physically attached. I'm pretty sure it handles all the protocol issues, but I don't know anything more about it, including where to get it or how much it costs.

 

[Shalmanese]

If you did get a laptop, you could reduce the wieght by ripping out all the non essential bits. Taking the screen and battery of an ultraportable would at least reduce the weight by half. Even more if you could remove the CD/HD/Floppy. In fact, it might just be easier to get a Via Eden mobo and chuck a CPU in there and a USB wireless modem. It would be cheaper and more configuarble than a laptop.

 

[Sir Fredrick]

It's still going to be too expensive.

 

[Fandu]

I'm in the very process of doing exactly what your doing right now. I'm using an Altera Max7000S CPLD on the robot itself for control and intelligence. My robot is completely self contained, but if you wanted wireless, it would be quite easy to use a PSoC, here's a great example of a wireless PSoC.

 

[Shalmanese]

I dont live in the US but I've seen Via Eden combos (Via mobo with onboard LAN/Video/Audio, 500Mhz Via C3 processor and 128MB of PC133) for less than $250 AUD which would mean around $100 USD by my estimates. I assume the actual robot is going to have its own power source so you could just hook that up to the mobo and chuck on either a old HD or just a floppy and you have the brains of your robot. I assume you dont need anything with an incredible amount of processing power. If you were to do stuff like image processing, you could pull out the C3 and chuck in a P3 1Ghz or so processor. All of it could be done for far less than $200

 

[blahblah99]

Easiest and most expensive way to do it is to get the single board computers (SBC's), a D/A card, a A/D card, and a timer card, and stack them all on top of each other. Run linux on it (store it on the diskonchip) and get the library files from the manufactorer of the SBC to access the cards. From there on, its all programming in C/C++.


A more difficult, but cheaper way to do it is to get a low-speed wireless modem chip build/design an interface to allow your PC to communicate with that chip. On the receiving end of that wireless modem will be a microcontroller to take the serial data and output the signals needed to control the drivers of the motors/solenoids/etc.

 

[Sir Fredrick]

I think this is what I need. If I can figure out how to make a board that allows the transmitter to hook up to the serial port, and then on the other end, a board that will control the robot based on signals received, I'll be good.

Unfortunately at this stage I have no idea how to do that.

 

[Xionide]

dude i got a 486 laptop with a bad battery that is collecting lots of dust and i would be will to get rid of it for cheap.i hate the thing and if someone could get use out of it i would gladly give it up.its the most expensive solitare machine ive ever used but its cheaper then a pda and its got pcmcia so it would probablt be cheaper. it a toshiba t191ocs. if you want it pm me and make an offer. like i said i hate this thing TAKE IT

 

[Moohooya]

There are several wireless serial/parallel port out there. However you'll have to buy something new which will be $$$. An old laptop may be your best bet.

Now in the good old days, people did this kind of stuff using an 8 bit CPU and a few K of memory. If you can get hold of an old 286 for free, that will do you as long as you do not want to use VB, .net or anything else. I'd run a simple DOS based app, written in mostly C with some C++ perhaps.

If you need more ports, consider using a PIC controller.

Laptops do tend to use lots of power. I don't know how you are powering this but if the laptop battery is dead remember that it will now be power by the robots onboad battery.

 

[Sir Fredrick]

Has anyone actually looked at that link?

 

[blahblah99]

Originally posted by: Sir Fredrick
Has anyone actually looked at that link?

no, cause we can't access it. Page not found!

Your best bet would be to use a BASIC Stamp. There's TREMENDOUS support for those modules and robot building.

 

[Sir Fredrick]

That's odd, the link works for me.
Well, what I linked to is a (relatively) cheap RF Transmitter and a Receiver.

Now we're talking, BASIC stamp, this is something that the above mentioned items require.
I don't know anything about BASIC stamps or how to use them. Where is a good place to learn more? Specifically, I need to use one to interface the serial port with the RF transmitter.

 

[blahblah99]

Originally posted by: Sir Fredrick
That's odd, the link works for me.
Well, what I linked to is a (relatively) cheap RF Transmitter and a Receiver.

Now we're talking, BASIC stamp, this is something that the above mentioned items require.
I don't know anything about BASIC stamps or how to use them. Where is a good place to learn more? Specifically, I need to use one to interface the serial port with the RF transmitter.

well the link is working now... odd. Anyways, a Basic stamp is nothing more than a micro-controller in which you can program using the BASIC language, which makes it extremely easy to program. And the size of the module is in the shape of a stamp, hence the name BASIC STAMP. It has built in serial communication and easily interfaces to that wireless transmitter/receiver you linked to.

You would develope your program using their development software and "burn" your code into the basic stamp by using a programmer.

On the sending end, you want to use the BASIC STAMP as an interface between the PC and the wireless transmitter. On the receiving end, you want to use the BS as an interface between the receiver and the robot.

If that's the case, then there is a maxim IC chip called MAX202E that'll interface the serial port to the transmitter. What it does is basically converts the +-12V at the serial port to 0 and 5V so you can send those signals to the transmitter. No need for a basic stamp for this section.

Where you will need the BASIC STAMP is at the receiving end though, as it will receive the 0/5V signals from the receiver, read the data, and send out the appropriate controls for your robot. Ie, you can make the letter 'F' to move your robot forward, 'B' backward, 'L' left, 'R' right. I believe the basic stamp has built in serial port functions, so all you need to program is something like ' Receive "F", 3 ' where 3 is the i/o line that the data line on the receiver is connected to.

Ok, that might be a little technical, but you will need it

If I were you, I'd get one of those Basic Stamp start kits that includes everything you need to start working on your project. Also, DO NOT get the 433Mhz Tx/Rx AM modulated pair because that's the WORSE frequency range to operate on. At the very least, get a 900Mhz AM modulated pair. Even better would be an FM modulated Tx/Rx.

 

[Sir Fredrick]

Thanks for all the good info. I'll look into a 900mhz version of the tx and rx, any suggestions where to get them?
Why is 433mhz so bad anyway? This robot is going to be in the same room as the computer controlling it, so range isn't very important, if that's the issue.

 

[blahblah99]

Because the FCC designated the 400Mhz band and the 900Mhz band as "Junk" bands. All sorts of crap flood these regions. I just had bad experience with the 400Mhz band at my lab. I dunno what runs in that region, but in the 900Mhz region you have wireless lans, cell phones, home phones, etc etc, but at least in a lab environment those signals are limited.

 

[DarkLance]

Kinda off topic... but WARPIG This is a article on using a basic stamp, for a paintgun, but it is pretty good. As look at the links on the left too, some more info. Also, you can buy the stamp at paralax, the site as the TX/RX thingys.... Parallax

 

[MrMikey]

Visit www.linxtechnologies.com . They have many wireless solutions. We used their wireless modules in a robot that we built in college. Depending on how much you know about electronics, they have many different products all the way from wireless modems to little modules that you can put on a printed circuit board that take care of all the RF stuff for you, and you can use it as a serial link with a little microcontroller.