pondering TP guts and such in Notebook file

diff --git a/Notebook b/Notebook
index 6565442d822508112922db9b7a5fad775888bdde..ab111a417377d4b9b71b0b6bd13b307e8112c89e 100644 (file)
--- a/Notebook
+++ b/Notebook
@@ -86,3 +86,60 @@
        + create PCB footprint for the GPS module 
        + create PCB footprint for the GPS antenna
 
+
+2009.10.09
+- flew lots of stuff last weekend at O'fest.  100g accel worked ok in G-Spot,
+  broke beeper presumably on landing with tangled chute.  board seems ok
+  otherwise, need to verify that baro sensor is still ok.
+
+- put out sample requests for gps passive patches from 3 vendors
+
+- when adding GPS, let's plan for passive patch loaded on the back of the 
+  board, plus a U.FL connector loaded on the top of the board with DC bias feed
+  to support external active antennas.  This probably means passive patch
+  direct to gps chip, then a dc blocking cap, a chip inductor for dc bias
+  injection, and the connector.  A suitable connector is:
+
+       WM5587CT-ND     Molex 73412-0110        0.70 in single quantity
+
+  Keith found gps active antennas with cable to U.FL connectors and Molex sells
+  cables with U.FL to bare leads, so this should cover the bases.
+
+- TelePyro doesn't need a CPU.  How about an SPI to I2C converter chip with
+  GPIO lines and an I2C ADC chip?
+
+  The Silabs CP2120 has 8 gpio lines but is only available in QFN20.  The NXP
+  part I discovered earlier, the SC18IS600, has 4 full gpio lines and 2 lame-o
+  pins, but is available in a hand-solderable version.  Add in a Maxim ADC, 
+  and something like this emerges:
+
+       DigiKey 568-3232-5-ND   NXP SC18IS600IPW,112    2.25
+       DigiKey MAX11603EEE+-ND Maxim MAX11603EEE+      4.00
+       Mouser  595-CD4508BM    TI CD4508BM             1.70
+
+  The 4508 has separate reset inputs and latch controls for each 4-bit latch.
+  The reset forces all outputs low, and the reset is an active-high input.
+
+  The NXP part has an active-low reset input, with 10-30k internal pullup.
+
+  The ADC has no distinct reset input.
+
+  A suitable SOT-23-5 reset controller is the MCP1319MT-29LE... it has a master
+  reset input we can ignore, and both active high and active low reset outputs.
+
+       DigiKey MCP1319MT-29LE/OTCT-ND                  0.70
+
+  This plus 8 copies of the pyro circuit on TM (FET and 4 resistors) and we're
+  good to go.  
+
+  Wonder if there are resistor networks it'd be worth trying to use to ease 
+  component placement?  Yes... these are 8 x 0402, more or less:
+
+       100 ohm         741X163101JPCT-ND               0.16
+       10k             741X163103JPCT-ND               0.16
+       27k             Y1273CT-ND                      0.18
+       100k            Y1104CT-ND                      0.18
+
+- another way to think about all this is that I could panelize a set of boards
+  all done in 2 layers, then treat that as a sub-panel I put N copies down of
+  to fill up a 33each.com max panel size.