Let's Make Robots!

WiFi - how can I talk to my bot with it?

I don't know much about networks and communications but most laptops and routers these days are wireless. Can we use this to interface with our bots?

A quick google on WiFi protocol told me that it is technically referred to as the 802.11 protocol.

The Xbee transceivers can also form a wireless network using the 802.15.4 protocol.

Is there some way of connecting a robot via WiFi using an Xbee? Rik has a blog on the subject. Unfortunately the router is too big for what I want and I still didn't understand how to use it.

Update:

WiFi.jpgAs all of you have been offering ideas and showing me products I did not find in my initial search I wonder if the answer hasn't been staring me in the face the whole time.

This is the WiFi / USB adapter I bought for my PC when I got the wireless router. 

It is small, low powered and relatively cheap. I suspect that once the network settings have been entered from the computer it would only need dirvers for communication.

Unfortunatly I have no idea how to implement this idea. Even if I can plug it into the PC to enter the network settings and then plugged it into a robot with say an Arduino or Picaxe brain. How would I then communicate with it?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

And the winner is!

Thanks for all your input. It is apparent to me that if I really want to use the 802.11 protocol that my computer and laptop use then the module found at Sparkfun by Robologist is probably best value for money. It is also very small and should interface well to any microprocessor.

08869-06-L.jpg

For now, the Xbee Pro is nearly half the price and has much better range. I can still communicate with my robots from the PC or laptop using a USB adaptor available for the Xbee modules.

xbee_60mw_250.JPGxbee_usb_explorer_250.jpg

 

 

 

 

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XBee-2.5-Manual.pdf1.49 MB

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This just dawned on me. The whole reason I were trawling nets through the google last summer, was exactly this quest. I needed a low cost wifi solution for a simple output device. You saw my blog, it's my version of W's "Mission Accomplished" banner.

Not!

The solution I ended up with (linksys router, with open version of firmware), is indeed power consuming. And when I tried to cram the whole project in a nice wooden picture frame, it would barely fit.

My point is: low power, miniature wifi hurts. Either your wallet or your pride. 

 


Oh, right. At the time, I found all the solutions that are mentioned again here. Didn't like them for their price. And some of them required learning stuff I was not prepared to research. That's how I stumbled upon letsmakerobots. [insert history here]

These days, I might be willing to learn all that new stuff. Because since then, I've got a great new and exciting hobby (jigsawing). Plus a couple of very clever friends who will most likely help to figure this stuff out. [looking at the evidence now]

I suppose that's why I found letsmakerobots, and stuck around.

Rik

I have no idea how to do what you are asking. I have no idea what people are suggesting. I have no idea if this would help at all. However, no one has thrown this out there so I will. --Again -no idea...

Picaxe's net server thingie

 

 

I forgot all about that. It is exactly what I was looking for. The drawback is like most picaxe stuff it is way overpriced and to be honest it is kinda big although the LCD does win back some points.

 

I also thought of hacking a USB dongle to get wireless on a robot my thoughs of how this is done are as follows.

Take a USB wire extender and split apart the 4 cables. Make the + and - wires connect to 6 volts of batteries and use the signal in and out go to the PC. Use hyperterminal to see what data is transmitted for it to set up and send data. 

Try to find a way to send and receive a packet. Since the dongle is powered by batteries I am assuming I could then unplug it from the PC and still have it connected to the router. At this point you would have to find a way to make a wrapper for the data sent from the dongle to your PC. When you send a "1" it is not sending just a "1". It is part of a packet with send/receive info, time to live data, etc. If you can hack how it creates the wrapper you could have it send data to your PC. If you can hack the wrapper you can also have your PIC take the wrapper off or know which part of the received signal contains the message.

Of course all of this is still theory, but I want to play with this someday. I just need to spare time and I need the spare time when I'm not sick like I have been today. 

Sounds good except that I would use a lowdropout regulator and run the dongle at 5V otherwise your experiment could be short lived. Even if the dongle is ok with 6V the computer and microcontroller will not like the increased voltage of it's output signals.

At this point I think the sparkfun unit is the winner for cost and ease of use.

I would have it on a seperate power supply. USB runs off of 6 volts and if it dips down too low when motors kick on, etc the dongle would lose the connection. Not as easy as the sparkfun method, but cheaper and I'm all about cheap. It is on my list of things I want to do, but it will likely be another few months before I pick it up since I have 2 other projects I want to work on first.

Messing around with one of these bad boys: 

 

 

http://www.coolcomponents.co.uk/catalog/product_info.php?cPath=25&products_id=33

 

 

 

Well was, im finding i can get anything to use to plug it into my breadboard and the pins are too close together for me to solder wires on. Im looking for an alternative right now, xbee is looking good.

 

Im also considering some easy radio modules as ive spotted a board with an atmega 32 and easy easy radio integration. I think maybe thats gonne abe the route i take, for now anyway.  

I like it's shock burst feature as a way of reducing power consumption. Very important for an autonomous robot. The price seemed reasonable too.

The Lantronix modules are possibly one of the easier ways to add wifi to a micro. Basically it's an embedded webserver that translates between your serial micro and wifi. Prices vary of course, but seem to be 100+ USD. Sounds similar to the thing robologist found at sparkfun, but more pricy. Ha.

The "hack a fonera" thing may be the cheapest way (10-20 USD on ebay) to get proper wifi, just not the smallest.

The price puts it out of the competition straight away. Size is important, which is why I'm not considering hacking a router like Rik did.