IR Wiring (Receiver)

[fuzzball27]

Now that I have my IR transmitter working with the NXT, I've been working with my IR Receiver (TSOP 1138). I've gotten the receiver working with my Arduino Uno by attaching the ground pin (to ground), the power pin to 3.3V power, and the out pin to an analog input.
Now I've hooked up the receiver to the NXT. The Receiver is made for a range of power levels up to 5V, so I have hooked up the power pin of the receiver to the green 4.3V wire on the NXT. I hooked the ground pin to the red ground wire, and the out pin to the white analog wire. So far I just get a reading of 0.
Any advice?

[philoo]

Maybe you don't see the pulses because they are too short? the analog input is sampled only every 3 ms. Perhaps it would be better to enter directly on digital I/O pin.

[fuzzball27]

hmm...how would I do that?

[mattallen37]

If you just want On/Off indication, you should be able to use an analog input. Remember though that the TSOP 1138 requires a 38 kHz carrier frequency. Another thing to think about is the fact that the TSOP may just float it's output with either a 0 or 1 signal. The NXT has a built in 10k pullup on the analog input pin.

You won't be able to do serial communication directly on the port without bit-banging. If you want to do UART communication with IR, I suggest you use the HT IR Link. The RCX mode is basically just IR UART (might be a single mode only allowing for 2400 baud, but you could still use it).

Are you looking to do just basic On vs. Off, or do you want to send serial streams?

If you are using the Arduino, you could use a GPIO for On/Off, or RS-485 or I2C for serial (any of these would be a wired connection).

What are you trying to accomplish with this project?

[fuzzball27]

My goal is to: (1) Gain a basic knowledge of IR communications using the resources at hand. (As you can see then, I have no idea what your post means, but thanks for the help.) and (2) To use the newly attained basic knowledge for basic NXT to NXT communication.

I understand that I can use BT for NXT-NXT communication; the reason I'm using IR is because it's for a school project.

[fuzzball27]

Are you looking to do just basic On vs. Off, or do you want to send serial streams?

Basic On/Off

[mattallen37]

If you just want On/Off, then use an IR LED (to transmit), and a lego light sensor in inactive mode (to receive). Phototransistors (the sensor that the light sensor uses) are usually very responsive to IR light.

The TSOP 1138 is far more than what you want for something like On/Off.

[fuzzball27]

Oh wow! Thanks, I wish I knew that when I started!