RS232 Interface Module.

[pdablue]

Hi,

When using a Compact Flash Serial Port adapter or a battery powered
Bluetooth module like the Firefly, you will need to convert the RS232
signals back to TTL/CMOS levels when interfacing to your embedded
hardware designs.

Small, low cost RS232 Interface modules are available on the Internet
from companies like Kronos Robotics and SparkFun Electronics. I am
using a module called the "Easy 232" from Kronos Robotics, see the
pictures below.

The "Easy 232" module has a 9-pin D-Shell connector, an RS-232 Interface
IC, some Capacitors, some jumper pins and some square header pins spaced
100 mils apart that can be plugged into a breadboard.

You will need a +5 Volt regulator to power the "Easy 232" module. I use
a 7805 voltage regulator to power the "Easy 232" module when it is plugged
up to either the Bluetooth Firefly module or the Compact Flash Serial Port
adapter cable. To power the +5 Volt regulator I use 8 AA batteries in a
plastic battery holder which connects to a 9-volt style battery connector
cable. The 9-volt battery connector cable is soldered to the 7805 regulator.
The 7805 is also solder to 2 jumper clip cables that are used to connect to
the square header pins on the "Easy 232" module to power the RS-232
Interface IC on the module.

Kronos Robotics sells the "Easy 232" Interface module in a kit form that you
assemble yourself. You can order the kits with Straight or Right-Angle 9-pin
D-Shell connectors.

Using Basic4PPC to program your PDA and a simple RS-232, cable or
wireless connection makes it easy to send commands to and receive
data from your embedded hardware designs.