2 - thinking more about a bluetooth TeleDongle variant. the basic idea is to
3 use a cc2540 soc to provide usb and/or bluetooth interfaces, and a cc1101
4 transceiver on one SPI port for our RF modes. Thus the code runs on the
5 bluetooth part unlike all our other designs.
7 swrr072 is a USB dongle design that shows use of a Johanson integrated balun
8 that's 0.68 at q100 with a pcb trace antenna on 2.4ghz .. pcb is 4 layers
9 and 1.616 x 0.632" .. looks like I could take the RF end of the design as is
10 for the 2.4gzh end. Maybe make the board wider to fit some hammond box?
12 using a Hammond 1591XXMTBU or 1591XXLTBU, could put the 2.4ghz antenna on
13 one of the long sides, and UHF SMA and USB+power switch on opposite small
14 sides? Can I find a suitable lipo to mount on the non-2.4ghz side?
17 http://cgi.ebay.com/3-7V-330mAh-lithium-battery-Polymer-Ipod-Mp3-GPS-/220713108705?pt=US_Batteries&hash=item336386c4e1
20 http://cgi.ebay.com/3-7V-765mAh-lithium-battery-Polymer-Ipod-Mp3-GPS-/220713108713?pt=US_Batteries&hash=item336386c4e9
23 http://cgi.ebay.com/LiPo-Lithium-Polymer-Battery-3-7V-450mAh-MP3-MP4-GPS-/300427570775?pt=US_Batteries&hash=item45f2e0ee57
25 52 x 34 x 4mm 600mAh *good choice?* $2.30 plus shipping
26 http://cgi.ebay.com/Lithium-Polymer-Battery-3-7V-600mAh-MP3-MP4-GPS-NAT-/290433981343?pt=US_Batteries&hash=item439f36db9f
29 - after much online discussion, the new plan is to use a cc1111 and a Rayson
30 BTM-182 bluetooth module .. the latter should be budgeted at about $15 each
31 in quantity 100 .. uses async serial, less dev effort, no regulatory issues
34 - Raysom BTM-182 peak current draw is 58mA, Roving Networks RN-42 peaks at 50mA
36 Raysom gave us a quote of $10 per delivered at q100
38 RovingNetworks replied to our quote request but we don't have a number yet
40 Rough estimate of cogs puts us at retail price of $150
43 - Pondering how much to clip off the SMA end of the PCB to ensure the SMA
44 flange fits inside the box.
46 Our connector needs 3.81 mm "above" the PCB which for TeleBT actually
47 means between the PCB bottom surface and the base of the box. The box
48 boss height is specified as 4mm, so that fits in a purely vertical sense,
49 but I'm worried about the box wall to base radius, and the fact that the
50 box walls aren't exactly vertical.
52 Hammond doesn't specify the radius between the wall and base of the 1551K
53 box. Given other things they do specify, it might be that 1 mm is a
54 conservative guess. The specification for the inside dimensions of the lip
55 around the lid is 10 mils smaller than the max PCB dimensions, and it *looks*
56 like that inside edge might be about where the wall radius ends. The drawing
57 shows the lid inside as 6.73mm less than box outside dimension, which seems
58 reasonably consistent with my estimate of a 2mm wall thickness, about 1mm
59 for the lid lip, and some mold tolerances. So, let's use the box lid lip
60 inside dimensions as a proxy for the box base inside dimensions until proven
63 So we need to peel 5 mils off to account for the box radius. The flange
64 itself is 40 mils. And I'm nervous about the guesstimates so I'll add
65 another 5 mils of margin. So we need to take 50 mils off the SMA end of
68 As a sanity check, on TeleDongle the closes screw hole is 78 mils from the
69 SMA edge of the PCB, which is 50 mils less than a maximum-size PCB would
70 have. If anything, the TeleDongle SMA ends up inside the wall a bit more
71 that necessary, such that tightening the SMA nut deflects the wall inward.
72 So, 50 mils might indeed be a good choice for TeleBT. We'll give it a try!