Trouble with RF-Link 4800

Wireless & IoT
1

Hello guys,

I have been trying to wirelessly control my bot from my PC.

I am using:

  1. Matlab to send ‘053’ to the serial port (after setting up the serial connection, fprintf( serlink, ‘%s’, ‘053’) )

2.A sparkfun Shifter Board to convert and invert the signal from PC’s serial port

3.Sparkfun’s RF-Link 4800 TX module to transmit the signal. I am supplying 6V to the shifter board and the TX module combined.

  1. Sparkfun’s RF-Link 4800 RX module on my bot. The data pin is connected to my basic stamp BS2SX.

I use SERIN 10, 2031, [DEC Data] on BS2SX to gather the signal from the RX module. Baudmode is 2031 corresponding to 1200 baudspeed and noninverted signals. Input pin is 10. If Data = 3, then my bot moves forward.

Now, when i simply connect the TX pin of the Shifter board to my Stamp’s Pin 10, i receive the signal- the bot moves forward.

But when I use the Rf-Link, the bot does nothin. I have tried to measure the voltage on the RX modules’ data pin using DMM and i get something (around 1V) when the signal is transmitted, 0V otherwise.

Also I am not using antennas. And the bot is no farther than 1/2 a metre.

This is the problem i am facing, As far as i see, the RX module may be receiving something but may be its corrupt. I have the motor and power cables around the RX module. I have twisted them ofcourse to reduce the noise but may be they are spoiling my party.

I will be extremely happy and glad to receive some help as this problem is driving me nuts for the past two days. Thanks

2

Just for the probable benefit for others: i have succesfully implemented my project.

The problem was i was not using serin command of the basic stamp appropriately.

By sending fprintf(filesrtream, ‘%s’, ‘A’) from matlab, and by using SERIN 10, 2031, [SerData] and checking if SerData = ‘A’ on the stamp worked perfectly.

There was absolutely no problem with the rf modules, infact i am very pleased about their performance. There was no need for any sync bits too ! Just put ‘A’ on one end( serial port) and get ‘A’ on the RX data pin. I didnt use any antennas too. Pretty neat ! Will have to test out the consistency at greater distances.

If anyone is doing similar project and want some help or want to discuss something, i will be more than glad to talk.