Introduction 
Interface Card
Software
Wireless
Credits
 
 
 

 

Wireless
Transmitting antenna

The design and positioning of the antenna is as crucial as the module performance it self in achieving a good wireless system range. The following will assist the designer in maximizing system performance:

  • The RF ground pin should be connected to a ground plane against which the antenna radiates

·    The PCB layout around the antenna track it self should be such as to give a 50 ohm impedance

  • The antenna it self should be kept as far away from source of electrical interference as physical possible

·       The specified power supply decoupling capacitors should be placed close to the module as possible and have direct connections to the relevant pins

·         The antenna "hot end" should be kept clear of any objects, especially any metal as this can severly restrict the efficiency of the antenna to receive power

·         The best range will be achieved with either a straight piece of wire rad or PCB track at 1/4 wave length (15.5cm at 433.92 MHZ)

Increased range may be achieved if the 1/4 of the wave antenna is placed perpendicular to and in the middle of a solid earth plane measuring at least 16 cm radius in this case, the antenna should be connected to the module using 50 ohm coaxial cable and the PCB track layout tips given above should be observed.

RF-RX module

The form of input signal, the input signal is RF signal received by the receiving antenna :

  • Power supply

  • Supply voltage: 2.7 to 5.25V typically 3V 

  • Supply current: "receive mode" 12mA

  • The form of output signal

  • The output is binary with:-

  • Data high = 0.7*VCC →VCC V

  • Data low = 0→0.3*VCC V

  • Operating temperature:

  • -20 to +70 Degc.