|Subject:||Re: [Paparazzi-devel] Maxstream 9Xtend problems|
|Date:||Mon, 18 Feb 2008 05:49:49 GMT|
The IR sensors are extremely sensitive to RFI - I have found no solution but have had some success with shielding the entire sensor with copper tape and using pass-thru RFI filters on all leads. Note that the thermopile cases are 1.7V, not ground as you may expect, so this makes shielding tricky. Another thing that helps greatly is to wrap the wires several times through ferrite rings. Also, the quality of the antenna plays a major role - I found that bad antennas caused more interference along with inferior modem range. Lastly, even the ground modem will interfere with the sensors if it is at 500mW or higher.
Note that the interference usually results in a static offset in the reading, not just noise. You should check by connecting the Tiny directly to the PC without any modems running to see the difference. You can also configure the airborne modem to "loopback" by connecting TX to RX. Then just send data thru the ground modem and the airborne will send it back. This way you can watch the IR data (thru a direct serial cable) and then simulate modem activity on demand. You can use the Maxstream software to send data to the loopback modem and this will also allow you to test modem range and diagnose your lockup problem.
-- Uttam Chandrashekhar <address@hidden> wrote:
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