Wireless link for homebuilt robots?

Depends on required bandwidth and range.

HTH .

Many people use Zigbee and wireless Ethernet (i.e. 802.11b/g/n).

-Wayne

Oops, I forgot to mention the Sparkfun bluesmirf based on Bluetooth.

-Wayne

The one I've been working has a 486 SBC on it, with a PCMCIA slot. So I use 802.11B

Thanks for the info so far.

How about some links to wireless hardware/software so we can implement them in hobbyist robots?

Thanks

Here's a good one! :)

Lol !

Den

Most hobbyist robots are still one-offs. Thus, there is very little standardization inside of them. The most common communication down in hobbyist robots is 5V asynchronous 8N1 signaling a fixed bit rate.

The Bluetooth BlueSmirf stuff from SparkFun has the nice characteristic that if you have a laptop of desktop with bluetooth, you only have to buy one of them. They can run up to 115200bps. There is really a lot of information over at on this open. The basic module costs $50-$65.

For Zigbee, most people are use the XBee and XBee-Pro proudcts. Each module costs between $20-$40. Digikey sells them. These are 3.3V modules that you connect to using two rows of 2mm sockets. You will need to purchase one module for each end of the communication. If you run on 5V, you need to worry about voltage level conversion.

Both the Zigbee and Bluetooth stuff are relatively low speed. The people who are pumping video over their connections are mostly using Wi-Fi (i.e. 802.11b/g/n). I'll point you at three solutions:

1) I have used the Linksys WRTLS54GS wireless router for about $100. It takes about 9 watts and has a full up Linux running on it. It has 5 Ethernet ports and a Wi-Fi port. It also has a USB port and two UART ports, although the UART ports require some surgery to access. I do not recommend this option right now because this router is hard to find, and even fewer people are willing to help you through the process of installing an open version of Linux on it. 2) Many people are using the 2 Watt BeagleBoard available from DigiKey for $150 (Digikey Part number: 296-23428-ND) This board does *not* have Wi-Fi built in, but you can plug in a Wi-Fi to USB adapter and it works just fine. There is a thriving BeagleBoard Google Groups community. It has a boat load of stuff on the board, include UARTs, USB, memory card reader, etc. Everything runs at 1.8 volts, so level conversion is needed. 3) At the last HomeBrew Robotics Club meeting, somebody showed us his robot using the bullet from Ubiquiti networks . This is a 1 watt device that has an antenna connector on one end and an RJ45 connector on the other for $40. Some sort of ethernet to serial converter is needed as well and those are still up in th $80 range. The bullet also runs Linux and the Ubiquiti web site explains how to access it.

Given that most hobbyists have access to Wi-Fi, that seems like it is going to be the long term winner. The days of power hungry Wi-Fi seem to be fading pretty fast.

Your request for pointers to examples of robots using this stuff is a reasonable one, but alas, most hobbyist robotics folks do not take the time to document their robots very well. I know I'm guilty of that sin.

I hope this helps,

-Wayne

Thanks for the great discussion Wayne.

TMT