Originally Posted by hebertjj
Well, I've been lurking on this thread since it started and gone thru all the previous XPS Tx thread and I'm finally ready to post.
1st, as a member of the human race I'd like to apologise to JIm for all the knuckleheads who keep pestering him with various versions of "is it here yet?" I think the next person that pulls that ought to be required to wash your car or mow your lawn before receiving anything from XPS again.
2nd, I LOL at Tony's suggestion of just requiring 4 AA. That would shut up the all the people worrying about what kind of battery to get. Good grief !!! Even 4 AA's would get you 20 hrs of operation; with auto shut down that ought to get me thru the summer. ( I'm still probably going with a cheap LiFe or LiPo pack.)
3rd, What does "16X over sampling" mean? Is the ADC sampling at 16x200hz or 3200hz (5 ms frame is 200hz, right?) ?
4th, What's the latest version to the TX box look like? Is it still the same as shown in the old thread?
5th, What's the 900mhz version about? If you're not supporting FPV, doesn't 2.4 ghz have more than enough range.
1 - No worries.
2 - 4 AA batteries would work as the dropout from the regulator is only .15v at full current. The stock display from ArtTech is a 5v display. We have a 3.3v option, but it does not fit correctly. So, for now, we will use the 5v version. This was the reason for requiring 6v, otherwise a single cell Lipo would be fine with the 3.3v display.
3 - 16x over sampling means that there are 16 samples (12 bits each) taken of each input channel. The samples are taken consecutively, so that each channel is scanned and the result stored in a buffer. After 256 scans (16 x 16 = 256) the data in the buffer is averaged. This eliminates 'bobble' from an input pot due to EMI/EFI or voltage changes in the system.
4 - Same box design.
5 - Our 900MHz DivBee module has a theoretical range of 43 miles. The theoretical range of our 2.4GHz DivBee module is about 7 miles, so quite a bit less than our 900MHz version. Real world and theoretical are two different things, with the installation and environment determining the actual range. 900MHz propagates better through metal and carbon fiber, and does not have an issue with water like 2.4GHz does.