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Back in the November 2012 issue, I wrote about the Telebot — an
Arduino-based deskbot operated via XBee wireless control. Telebot's main
operations are controlled by a human, but it's not a simple stop-and-go
contraption. Low level functions are handled by the onboard Arduino
microcontroller. The robot can react to touch and distance sensors,
automatically avoiding obstacles for you.
Let's go even further with the Telebot. In addition to controlling the robot
remotely, how about having the Telebot send back video pictures of the
landscape it sees. Wireless security cameras are relatively low cost — some
under $40, including both camera/transmitter and receiver — and easy to
use on a mobile robot. The camera is operated using a battery or other
convenient power supply.
This month, I’ll describe how to add video to any robot — remotely controlled or not. In addition to simply feeding back a picture of whatever is in your bot’s path, I’ll also cover how to overlay
textual data onto the video, so you can get real time
telemetry of your machine’s current status.
My prototype Telebot is shown in Figure 1;
you’re free to adapt the ideas to whatever robot
design you currently have, or plan to develop.
different RF frequency within the 2. 4 GHz band.
You can tell if your camera and XBee are messing each
other up by monitoring the video image when you place
the XBee remote next to the camera. If there’s a problem,
The Basics of
Figure 2 shows a small wireless camera along
with its paired receiver. These setups are available for
under $75 — sometimes less — and are easy to use.
The camera is operated by its own nine volt battery,
while the receiver uses a plug-in power adapter. The
video output of the receiver connects to any
I’m using an NTSC camera and receiver, so any
NTSC-compatible monitor will do. A small 7” LCD
monitor is ideal, since these have a power jack on
them for low voltage (usually 12 volts or less)
operation. Rig up a battery for both the receiver and
monitor, and you can create a fully portable video
The standard frequency band used by wireless
video cameras is 2. 4 GHz, which just so happens to
be the same band used by your XBee radios. There is
a chance that the video camera will interfere with the
XBee, and vice versa.
However, this problem is mitigated by using a
multi-channel wireless camera where you can select a
FIGURE 2. You can add video to your robot
with a low cost camera and receiver pair, like this one.
The camera contains its own transmitter and antenna,
and is designed for battery operation.
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