Transmit Power

Hi,

I bought a couple of Wixel’s to experiment with in a remote sensor application. My goal is to be able to scatter them throughout the house and have a central micro controller logging data from all of them. The problem I’ve run into at this point is that they seem to be incredibly short-range. If I move to the door of my office I still get a round trip signal through, but if I step to the side where I don’t have a direct line of sight to the other transceiver, I lose the signal completely. Is there possibly something I’m missing I the set up, or are they strictly short-range (10-20 feet) line of sight devices?

Hello.

I’m sorry you are having trouble getting good performance out of your Wixels. When we were testing them we got them to communicate from 50 feet away, through several walls.

I recommend reading the “Ensuring a Good Radio Signal” section of the Wixel User’s Guide, especially the parts about trying different frequencies and removing objects close to the antenna.

You can use the test_radio_signal_rx and test_radio_signal_tx apps in the Wixel SDK to quantify how good your signal is, which should help you while you are trying to improve it.

–David

Running the tx/rx pair, with the two radios sitting on the desk next to each other I the output is:

 78,   -34,    87
 81,   -35,    94
 77,   -35,    91
 69,   -35,    91
 72,   -35,    93
 74,   -35,    99
 73,   -35,    98
 78,   -35,    97
 78,   -35,    93
 76,   -35,    94
 72,   -35,    94
 67,   -35,    94
 72,   -35,    95
 76,   -35,    97

If I’m reading the documentation correctly, that seems to indicate that the received signal strength is lower than I would expect given that they’re only a couple of inches from each other and the packet-loss is pretty insane at about 30%. It really seems like there’s something going on here. I’m going to download the Windows stuff so I can try changing the channels some and I’ll post some more information here.

After playing with the channel parameter a bit, I’m really not seeing a whole lot of improvement in the packet-loss and/or power levels. Even holding both radios in the air so there’s nothing within 5-6" of them except the USB cable and the other wixel, the numbers are really pretty consistent.