version of the acquisition chip, and costs less. That would support one
pressure sensor and one load cell. Then make it possible to add on other
acquisition boards somehow.
+
+2020.10.20
+- sticking with the ADS131A04 and routing the extra two inputs to the header
+ means that supporting 2 burn wires for the strand burner daughter card is
+ dead simple. it also means that adding a second load cell and pressure
+ sensor if required on a daughter card would also be dead simple.
+
+- for strand burner, I need a daughter card that provides a high-side switch
+ for pyro power (since I need a common ground through the system), and has
+ resistors for 2 ADC inputs hooked to burn wires. Bring this all out through
+ a 5-pin connector to the outside that hooks to the strand burner end. We'd
+ also use the existing pressure sensor channel, but not use the load cell.
+
+ So, firmware wants to log all 4 analog inputs all the time. For a test
+ stand run, only the pressure sensor and load cell are relevant. For strand
+ burner, pressure sensor and the two burn wires are relevant.
+
+- for Jamie / Estes, I need a daughter card that adds at least 4 thermistor
+ inputs, and support for their Sony camera trigger thing.
+
+- 40 pin header and mating female connector for daughter cards w/q1 pricing
+
+ header Sullins PRPC020DAAN-RC DK S2011EC-20-ND 0.90
+ mating Sullins PPPC202LFBN-RC DK S7123-ND 2.38
+
+- high-side switch for strand burner daughter card. This is an 8-SO part
+ good to 28V and 21A, 50 mOhm on resistance. Should be trivial to make
+ work on a 2-layer PCB
+
+ ST's VN7050ASTR, DK 497-15993-1-ND, 1.58
+
+ Means we need multiple header pins carrying pyro voltage to get enough
+ current, since the header spec is 3A per pin. 2-4 pins each for v_pyro
+ on the pin 1 end, and gnd on the other end should do.
+
+- for strand burner daughter, use CUI TB003-500-P06BE 6-position 5mm pitch
+ screw terminal strip, supports 14-26 AWG wire, 10A per pin continuous,
+ DK 102-6165-ND, $1.01 q1
+
+2020.11.15
+- thinking about connectoring again. for the base TeleStatic, we need to
+ have DC power in for battery charging, pyro output, pressure sensor, and
+ load cell.
+
+ For battery charging, use the same powerpole and 3d-printed part we use on
+ TeleFireEight.
+
+ For pyro output, let's try a panel-mount single 3-wire AC socket:
+
+ Schurter 4300.0701, DK 486-1082-ND, $1.48 q1, needs a complex routed
+ opening, has lugs for soldering wires. Sides squeeze to remove if
+ if needs to be replaced. Should be easy enough to CNC mill opening.
+
+ For the pressure sensor, a 3-conductor 1/4" audio plug seems like a great
+ plan, use metal-shell Switchcraft parts. Couple that with shielded twisted
+ pair cable.
+
+ For the load cell, we need 4 conductors plus ground, so a 5-pin XLR is an
+ economical possibility.
+
+ male chassis IO-XLR5-M-BK-JL DK 1937-1135-ND 4.65
+ female cable IO-XLR5-F-BK DK 1937-1035-ND 5.25
+
+ Gary's load cells use Amphenol PC04E-10-6P, which is $64/ea from Newark!
+ Could offer to deliver him a cable with one of those on one end and what
+ we want on our end?
+
+ Cable that's 2 twisted pairs, shielded with drain wire, would suffice for
+ the load cell and could be used ignoring one pair for the pressure sensor
+ if desired. Here's one with grey PVC jacket and foil shield:
+ Alpha M4473 SL005 DK M4473SL005-ND 51.79/100ft
+
+2021.02.09
+- Grainger carries Rust-Oleum "Industrial Choice Spray Paint in Gloss OSHA
+ Safety Purple for Masonry, Metal, Plastic, Wood", Item #6KP15, $6.60 per
+ 12oz can. The idea of test stand electronics being purple with orange
+ logo decals vs TeleFireEight being orange with purple decals might make
+ sense?
+
+2022.05.22
+- looking at firmware for v4 board.
+
+ ads131 has driver for ADS131A0X, not quite working?
+ bdale-ui work on teststand ui
+
+ - created new branch telestatic-v4 from master
+ - merged bdale-ui, resolving conflict in altoslib/AltosCSV.java
+ - merged ads131, resolving conflict in src/kernel/ao_data.h
+
+- improper gain setting or higher than expected mV/V on load cell can easily
+ drive INA125 output above the 5V allowed by ADC input. adding a 5.1V, 500mW
+ zener between INA125 and ADC to clamp that and protect the ADC
+
+
+2022.09.17
+- and now, for something completely different...
+
+ What if I re-think TeleStatic to use an ESP32-S3 chip with integrated WiFi
+ radio? Imagine a board in an ammo box with an SMA female and a cheap WiFi
+ whip on top of the box. Looks over the air like an access point with web
+ server. Take any client device (laptop, tablet, phone) with a web browser
+ and use it to talk to the box, check status, initiate a burn, etc. If we
+ include an SD card, then data is stored on board and can be downloaded via
+ WiFi, or pulled out and parsed later.
+
+ One really big win with this approach is that ALL the software involved in
+ operation lives on the board. Only post-processing tools might want to live
+ on a separate computer. And, frankly, if we make "raw" data avaialble in
+ CSV form and have on-board plotting with pdf output .. we'd be about done?
+
+ The onboard 12-bit ADC seems pretty lame, but I've been planning an off-SOC
+ SPI attache ADC anyway, so who cares? The pyro circuit, LED outputs,
+
+ The ESP32-S3 is under $3 each at Q1 in stock at DK, a 56 lead QFN'ish thing.
+
+2022.09.19
+- sadly, the ESP32 series requires a pile of binary firmware blobs to make
+ the wifi and BT stuff work, and because those execute on the same processor
+ and must be linked to the firmware, it just isn't legally possible to write
+ GPL'ed code for this processor series. Sigh.
+
+ So, Keith suggests I use an available SAMD21 part with 256k flash and 32k RAM
+ and an external standalone wifi peripheral, like the uBlox NINA-W131-03B.
+ You talk to it with an AT command set, so we don't have to deal with a binary
+ firmware blob. Amusingly, this seems to have an ESP32 inside!
+
+- bought a NINA eval board to play with .. should be able to hook it to one of
+ my existing proto boards?
+
+2022.11.10
+- looks like I have 25 pieces of STM32L151VCT6A, which might be well used for
+ an initial TeleStatic board run? 256k flash, 32k RAM
+
+
projects / hw / quantimotor / blobdiff