27980 Datasheet 27980 | P1-P3

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©Parallax, Inc. • 433.92 MHz RF Transmitter and Receiver (#27980, #27981) • v1.0 1/06 Page 1 of 8

Parallax 433.92 MHz RF Transmitter (#27980)

Parallax 433.92 MHz RF Receiver (#27981)

General Description

The Parallax 433.92 MHz RF Transmitter allows users to easily send serial data, robot control, or other

information wirelessly. When paired with the matched RF Receiver, reliable wireless communication is as

effortless as sending serial data. The power-down (PDN) pin may be used to place the module into a low

power state (active low), or left floating (it is tied high internally).

Features

 High-speed data transfer rates (1200 ~ 19.2k Baud depending on controller used)

 SIP header allows for ease of use with breadboards

 Compatible with all BASIC Stamp

modules (including BS1 and Javelin Stamp) and SX chips

 As easy to use as simple SEROUT/SERIN PBASIC instructions

 Power-down mode for conservative energy usage (longer battery life)

 Line-of-sight range of 500 feet (or greater depending on conditions)

Application Ideas

 Remote Controlled Boe-Bot

robot

 Wireless data acquisition

 Remote sensors and triggers

Device Information

Theory of Operation

Short for Radio Frequency, RF refers to the frequencies that fall within the electromagnetic spectrum

associated with radio wave propagation. When applied to an antenna, RF current creates

electromagnetic fields that propagate the applied signal through space. Any RF field has a wavelength

that is inversely proportional to the frequency. This means that the frequency of an RF signal is inversely

proportional to the wavelength of the field. The Parallax RF modules utilize a frequency of 433.92 MHz,

this works out to be a wavelength of approximately 0.69 meters (2.26 feet, or 7.3e-17 lightyears).

433.92 MHz falls into the Ultra High Frequency (UHF) designation, which is defined as the frequencies

from 300 MHz ~ 3 GHz. UHF has free-space wavelengths of 1 m ~ 100 mm (3.28 ~ 0.33 feet or

1.05e-16 ~ 1.05e-17 lightyears).

©Parallax, Inc. • 433.92 MHz RF Transmitter and Receiver (#27980, #27981) • v1.0 1/06 Page 2 of 8

Pin Definitions and Ratings

Transmitter (#27980)

Pin Name Function

1 PDN Power Down - active low, pulled high internally so may be left floating

2 DATA Data Output

3 5v Power – connect to +5v DC (such as Vdd)

4 GND Ground → 0 v (such as Vss)

Transmitter Supply Current:

At Logic High Input: 5.1 mA

At Logic Low Input: 1.8 mA

Low Power mode (PDN): 5

µA

Receiver (#27981)

Pin Name Function

1 RSSI Received Signal Strength Indicator

2 PDN Power Down - active low, pulled high internally so may be left floating

3 DATA Data Input

4 5v Power – connect to +5v DC (such as Vdd)

5 GND Ground → 0 v (such as Vss)

Receiver Supply Current:

During Operation (

High or Low

): 5.2 mA

Low Power mode (PDN): 28

µA

PDN

Pulling the power down (PDN) line low will place the transmitter/receiver into a low-current state. The

module will not be able to transmit/receive a signal in this state.

RSSI (receiver only)

Received Signal Strength Indicator. This line will supply an analog voltage that is proportional to the

strength of the received signal.

Calibration

When initiating communication between the RF modules, a sync pulse should be sent to re-establish the

radio connection between the modules. Sending several characters can accomplish this, however

sending a pulse (which maintains a high state during the synchronization) is more efficient:

√ For BS1s the following code line sends an appropriate sync pulse:

PULSOUT 1, 300

√ For BS2s the following code line sends an appropriate sync pulse:

PULSOUT 8, 1200

√ For Javelin Stamp modules the following code line sends an appropriate sync pulse:

CPU.pulseOut(300, CPU.pin8);

(Note: this line assumes that I/O pin 8 is connected to the DATA line on the transmitter)

Connection Diagrams

Transmitter (#27980) Receiver (#27981)

P1-P3 P4-P6 P7-P8

27980

Mfr. #:

Buy 27980

Manufacturer:

Parallax

Description:

LS-1700 316 S.S., PTFE, N.C., 20 VA

Lifecycle:

New from this manufacturer.

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Products related to this Datasheet

27980