Is there X-BAND Sensor Directionality Absorption Material?
josep01972
Posts: 4
Hi All,
I have been searching for a while and have see this question answered a few times, but not to my needs: How do I make Parallax's X-Band sensor one-directional? I am trying to use the sensor for a pest deterrent application using an attiny85. For my setup, a window overlooks the area where I want to keep out neighborhood cats. The idea is for the detecting device to see the movement from inside the window and then send a message to the sprinkler system to turn on for a bit in the area to scare off the cats. There is an arduino hooked up to the sprinkler system listening for on/off commands that would come from the detector. Because the detector is inside of the house, I cannot detect outside movement using PIR (I tried through the window, no luck). So I decided to try the X-Band sensor.
I have every other aspect of the project working except the sensor itself. As others have pointed out, the sensor detects movement in a radius, so movement behind and to the sides of the sensor is also detected. I tried to fiddle with the sensitivity so that the back and sides would not detect movement unless it was very close to the sensor (actually the sensor is inside of a black project enclosure box), but because the sensor has to detect movement through the window, by the time the sensor is calibrated so that movement from behind is not seen, movement from the front and through the window is not detected either. Obviously, I would like the sensor to work like PIR or sonic where you detect movement in only on direction. I have tired using aluminium foil and a cut out pringles can inside the small project box to block out movement on back and side to no avail. I have seen others use a big soup can (posted somewhere in this forum), but that solution is not practical for my aesthetic needs.
During my research on this, I found a poster saying there exists material that can absorb the radar energy. This seems ideal for my situation. I think it would be great if Parallax would offer a version of the X-Band product that is truly one directional. Maybe even offering as a add-on radar absorbing material for DIY'ers to create any directionality they want. In the mean time, can someone point me in the right direction for the absorption material? Is there really such a thing? Can I make the material myself?
Thanks a lot for any help!
Jose
I have been searching for a while and have see this question answered a few times, but not to my needs: How do I make Parallax's X-Band sensor one-directional? I am trying to use the sensor for a pest deterrent application using an attiny85. For my setup, a window overlooks the area where I want to keep out neighborhood cats. The idea is for the detecting device to see the movement from inside the window and then send a message to the sprinkler system to turn on for a bit in the area to scare off the cats. There is an arduino hooked up to the sprinkler system listening for on/off commands that would come from the detector. Because the detector is inside of the house, I cannot detect outside movement using PIR (I tried through the window, no luck). So I decided to try the X-Band sensor.
I have every other aspect of the project working except the sensor itself. As others have pointed out, the sensor detects movement in a radius, so movement behind and to the sides of the sensor is also detected. I tried to fiddle with the sensitivity so that the back and sides would not detect movement unless it was very close to the sensor (actually the sensor is inside of a black project enclosure box), but because the sensor has to detect movement through the window, by the time the sensor is calibrated so that movement from behind is not seen, movement from the front and through the window is not detected either. Obviously, I would like the sensor to work like PIR or sonic where you detect movement in only on direction. I have tired using aluminium foil and a cut out pringles can inside the small project box to block out movement on back and side to no avail. I have seen others use a big soup can (posted somewhere in this forum), but that solution is not practical for my aesthetic needs.
During my research on this, I found a poster saying there exists material that can absorb the radar energy. This seems ideal for my situation. I think it would be great if Parallax would offer a version of the X-Band product that is truly one directional. Maybe even offering as a add-on radar absorbing material for DIY'ers to create any directionality they want. In the mean time, can someone point me in the right direction for the absorption material? Is there really such a thing? Can I make the material myself?
Thanks a lot for any help!
Jose
Comments
-Phil
We can take regular bath tub silicon calk and mix it with regular cornstarch, and it makes a more scuptable clay-like consistency, and it dries in 20 minutes instead of 20 hours. I have also used grout and mortar to color match the fill in the border between the tiles and the wall etc.
So perhaps you could mix silicone with carbon and get the effect you want. I don't know about the geometry of the wave guide/absorber. If carbon is the absorber, though, this might be a place to start.
As I understand it (which is not much) the shape of the wave guide play a big part in direction and sensativiy for a given frequency.
Please post if you make any progress.
-Phil
Thanks for the replies. As far as the horn antenna, I googled them and maybe I am missing something, but how do I detract form the back of the sensor with them. Do I place the antenna behind it?
Thanks,
Jose
Jose