Spare arduino as serial/USB adaptor?

I’m going to be using an RF link for a remote sensor. I thought I’d save $15 and attach the transmitter to one board (Diecimila) and the receiver to my old board (NG). Then I could read the values off the NG via USB.

I’m testing this out with just a wired connection and it isn’t working. Here’s the details:

Transmitter is running this program:

byte i = 0;

void setup() {

void loop() {
  Serial.print(i, DEC);
  i = (i + 1) % 10;

Connecting the USB directly to that board, it works fine.

I originally had the receiver reading and then rewriting, but then I realized that hardware-wise this couldn’t be necessary. So the NG is running a “blank” program. The physical part is that both boards are running off of common +5 and gnd, there’s a wire from the transmitter’s TX pin to the receivers RX pin and USB is connected to the receiver.

Another idea is to run SoftwareSerial on the receiver, read from that and then write to hardware serial. But the SoftwareSerial says it will drop any bytes received while not in read() and I don’t want that…

Never mind, I think I have this working. It’s complicated by NG bugs, but I think the deal is the transmitter has to not write in DEC and the receiver DOES have to read and rewrite. In any case, that seems to work…

No, I have a problem after all.

I got the RF units. I know they physically attached OK and aren’t defective because I have seen data come across. Just not reliably and now not at all. I’ve gone through many permutations of code (hardware serial, software serial, different data encoding schemes and timing schemes, etc) Now I have pretty much this exactly layout and code running:

On the receiver I get: Nothing. Not even noise. That has to be impossible. Also, on the transmitter I don’t see the transmit LED light up intermittently as I think I should.

Something that would help ENORMOUSLY is if I could independently verify that the transmitter is transmitting without necessarily having the receiver receiving. Is there some way I can tell this? A radio or a dead simple circuit or something?