William Wong
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ED Online ID #13441 |
September 8, 2006
Unlike many of the other wireless kits I have examined, The MS Series Encoder/Decoder from Linx Technologies does not have a microcontroller to program. Instead, its transmitters (encoders) and receivers (decoders) can be used in a standalone mode or in conjunction with a microcontroller that you add. The LR series operate in the 260-470MHz band using amplitude modulation (AM). They can operate at distances up to 3000 feet.
Linx’s wireless chips have a serial. The serial interface is designed to work with a separate microcontroller or with chips like the MS Series encoder/decoders. These mate with the LR series RF devices. They can convert parallel data to serial and provide addressing for unique identification of a device. The combination is targeted at applications such as keyless entry systems, home and industrial automation, and remote status and monitoring.
The two boards included with the system are identical in layout (see Figure 1) but not in components. The master module contains a USB to serial chip that allows the board to interface with a PC and the provided demo software (see Figure 2).
Both boards have a large prototype area, status LEDs and a 9V battery for mobile use. The master has a wireless transceiver chip while the slave has a transmitter. The latter also populates the pushbuttons switch area.
Getting the demo software up and running is a relatively trivial exercise. There is not much to do after you check out the basic system until you start adding your own hardware to the prototype area or start building an application to interface via the USB port.
The wireless interface is very simple but it lacks the higher level protocol and handshaking found in 802.11 and 802.15.4. The transmission speed is limited to 28.8Kbuad as well as the distance between the boards. The other baud rates supported are 2400, 9600 and 19200 baud. The LR series of chips from Linx is limited to the two lower baud rates.
If you don’t need the speed, reliability or flexibility of things like 802.11 or 802.15.4 then definitely take a look at Linx’s solutions. They are simple, easy to use and have be incorporated into products for many years.
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