RB-Ons-02 Problem

Help & Support Robot Parts
1

I have been working with this transmitter/receiver pair to inport sensor data. Basicall, I have a ChipKIT Uno pin 1 hooked to the transmitter and another Uno hooked to the receiver. Below is a description of my problem.

system diagnostic notes:- system fails to communicate when the RF transmitter and receiver are in the circuit

  • system works as designed when RF is bypassed (i.e. TX from transmitter pin 1 hooked directly to RX receiver pin 0)system is sending serial data one way from transmitter to receiver
  • reduced baud rate from 9600 to 1200
  • does not work with RF, does with RF bypassed
  • monitored TX pin 1 with oscilloscope. input is clean. serial packets look good
  • monitored RX pin 0 with oscilloscope. serial packets look good, but lots of extraneousbits popping up randomly. rise and fall of bits are crip. receiver output voltage - 3.5 V high, 0.3 V low
  • removed data input from transmitter, see a rather continuous string of output pulses from receiver- removed power from transmitter and receiver output clean
  • connected transmitter RF output to 10 k resistor to receiver RF input. still see extraneous bits
  • monitored system frequency with portable wide band receiver. did not hear any extraneoussignals other than those produced by transmitter
  • system is powered from USB port on laptop, and is clean

Two questions: Have other had similar problems? What else should I check?

Thanks k

2

Hio Carlos - I understand the Rb-Ons-02 is very basic communications. The extra pulsing output of the transmitter when the data in is at ground is troublesome. The serial on this project is set to send a message every 500 msec. In between, there are a bunch of pulses (unfortunately I cannot tell the number from my oscilloscope) but is probably in excess of a hundred or so. I’m not sure I can clean up that mess in software.

I will look at the Rb-Spa-110 and see where we go. Unfortunately, this project is very cost sensitive.

Thanks for the quick reply Ken

3

Hi Ken,

Rb-Ons-02 is a very simple RF communication pair that does not offer any protocol or data integrity checks. As such, the receiver outputs directly what it receives (or think it does), you will then need to clean the received signal in order to use it more reliably.

If you want a drop in replacement for a wire for doing serial communication, we recommend using XBee modules (RB-Spa-110) which output clean serial data by default.