So, I've acquired a Radio Frequency transmitter that runs with Arduino. The problem? The pins on the transmitter don't match up with the pins on the Arduino (its a Duemilanove).

The pins on the transmitter read: SET, AUX, TXD, RXD, EN, VCC, GND.

I'm a beginner in electronics, but I've done a little searching online. I assume that the TXD needs to be connected to an RX port on the Arduino, and the RXD should connect to a TX port on the Arduino. Also, GND to GND. I believe VCC connects to 5V on the Arduino as well, but I'm not sure. If you know if any of these are right or wrong, please tell me :)

Now, I wasn't really sure about SET, AUX, or EN. I didn't find much on these in relations to Arduinos. Basically, none. Any ideas on where on the Arduino these would wire to?

And, any ideas on how to wire them? I'd assume I'd need a circuit board or a bread board, but like I said, I'm an electronics newbie.

The link the the transmitters is this, by the way: http://www.goodluckbuy.com/apc220-wireless-communication-module-for-arduinousb-converter.html

Any help would be appreciated. I'm also assuming that the program to operate this would be the same for a typical Serial Port communication? That would probably be a question for the programming boards, but if you know, please tell me :)

So, like I said, any help or advice on where to connect these pins or just how to use the device in general would be greatly appreciated.


Yes, you'll need a bread board to test this.

You are right, the RX goes to the TX, the VCC to 5V (although you should check if it runs on 5V or 3,3 to be sure, and the GND together.

EN is probably the enable signal for the radio, which should be high (unless there is a bar over the EN or a slash before it in the board, in which case should be connected to GND.

SET most likely enables you to enter configuration mode on the device...

AUX, I have no idea...

But then again, without reading the manual I'm just assuming on the meaning of these from past experience. :\

ugh, why did you cross post this question?


Thank you… The device didn’t come with a manual so I’m going of… forums really.

And, no, that was a separate board from a while ago… With completely separate questions :slight_smile: The first one was for simply how to use… This one was specifics… That didn’t really relate specifically to the transmitter.

Thanks for your help! :slight_smile:
If anyone else glances at this, I wouldn’t mind any more advice as I’m going off of… like nothing.

the manual comes up as the first google result when you search for the name of the device, a copy of the manual was also posted in the last thread you made about this device, along with another link that goes into a lot more detail about using it, and photos of exactly how to hook it up to an arduino along with source code demonstrating how it's used... so what more are you looking for? You have absolutely everything you need to hook this up already, if there's a specific part that you are having trouble understanding then we may be able to help you better.

There appears to be setup software to configure these modules, for instance setting the on-air baud rate, RF channel, RF power - you'll certainly need to set the channel to be within the ISM band (433.000 to 434.775 at 10mW or less in region 1) It looks like the device by default is in analog TV band at 475MHz...

[edit it looks like the region 1 legal version is the APC220-43 which tunes from 418 to 455 and defaults to 434MHz which is in the ISM band - its still too powerful by default (20mW instead of 10mW). The manual for the APC220-43 is much more informative BTW]