1 - switches to use are DK CW102-ND
3 - move switches down box so they aren't spread out into gasket rim area
5 - add another 2-pin header to PA8 (MCO) so we can sample the master clock to
6 calibrate the SOC oscillator, which means moving the RED RF strength LED to
10 - The more I think about this project, the more I want to go back to a board
11 that just does one each load cell and pressure sensor. I just haven't ever
12 actually used anything else.
14 Discussion with Joe Bowen made it clear that if I were to design such a
15 board so that it could take option cards, and/or had just a pile of basic
16 analog inputs and maybe switch outputs available, that doing other stuff
17 could be fun, and we'd "grow the system as we need to". Every time I tried
18 to pin him down on specs, all I got was vagueness.
21 - Maybe the right answer is to move to the ADS131A02 which is the 2-channel
22 version of the acquisition chip, and costs less. That would support one
23 pressure sensor and one load cell. Then make it possible to add on other
24 acquisition boards somehow.
27 - sticking with the ADS131A04 and routing the extra two inputs to the header
28 means that supporting 2 burn wires for the strand burner daughter card is
29 dead simple. it also means that adding a second load cell and pressure
30 sensor if required on a daughter card would also be dead simple.
32 - for strand burner, I need a daughter card that provides a high-side switch
33 for pyro power (since I need a common ground through the system), and has
34 resistors for 2 ADC inputs hooked to burn wires. Bring this all out through
35 a 5-pin connector to the outside that hooks to the strand burner end. We'd
36 also use the existing pressure sensor channel, but not use the load cell.
38 So, firmware wants to log all 4 analog inputs all the time. For a test
39 stand run, only the pressure sensor and load cell are relevant. For strand
40 burner, pressure sensor and the two burn wires are relevant.
42 - for Jamie / Estes, I need a daughter card that adds at least 4 thermistor
43 inputs, and support for their Sony camera trigger thing.
45 - 40 pin header and mating female connector for daughter cards w/q1 pricing
47 header Sullins PRPC020DAAN-RC DK S2011EC-20-ND 0.90
48 mating Sullins PPPC202LFBN-RC DK S7123-ND 2.38
50 - high-side switch for strand burner daughter card. This is an 8-SO part
51 good to 28V and 21A, 50 mOhm on resistance. Should be trivial to make
54 ST's VN7050ASTR, DK 497-15993-1-ND, 1.58
56 Means we need multiple header pins carrying pyro voltage to get enough
57 current, since the header spec is 3A per pin. 2-4 pins each for v_pyro
58 on the pin 1 end, and gnd on the other end should do.
60 - for strand burner daughter, use CUI TB003-500-P06BE 6-position 5mm pitch
61 screw terminal strip, supports 14-26 AWG wire, 10A per pin continuous,
62 DK 102-6165-ND, $1.01 q1
65 - thinking about connectoring again. for the base TeleStatic, we need to
66 have DC power in for battery charging, pyro output, pressure sensor, and
69 For battery charging, use the same powerpole and 3d-printed part we use on
72 For pyro output, let's try a panel-mount single 3-wire AC socket:
74 Schurter 4300.0701, DK 486-1082-ND, $1.48 q1, needs a complex routed
75 opening, has lugs for soldering wires. Sides squeeze to remove if
76 if needs to be replaced. Should be easy enough to CNC mill opening.
78 For the pressure sensor, a 3-conductor 1/4" audio plug seems like a great
79 plan, use metal-shell Switchcraft parts. Couple that with shielded twisted
82 For the load cell, we need 4 conductors plus ground, so a 5-pin XLR is an
83 economical possibility.
85 male chassis IO-XLR5-M-BK-JL DK 1937-1135-ND 4.65
86 female cable IO-XLR5-F-BK DK 1937-1035-ND 5.25
88 Gary's load cells use Amphenol PC04E-10-6P, which is $64/ea from Newark!
89 Could offer to deliver him a cable with one of those on one end and what
92 Cable that's 2 twisted pairs, shielded with drain wire, would suffice for
93 the load cell and could be used ignoring one pair for the pressure sensor
94 if desired. Here's one with grey PVC jacket and foil shield:
95 Alpha M4473 SL005 DK M4473SL005-ND 51.79/100ft