{
 "_note": "Electrical choices the simulation checks. Edit here, rerun power_sim.py. v01 kit build (ADR-0013): plug-in or through-hole parts only. ADR-0014: one bigger cell; runs continuously on a USB-C phone charger.",
 "power_switch": "pololu_2810",
 "power_switch_part": "Pololu 2810 Mini MOSFET Slide Switch LV between the charger LOAD and everything after it; the shell's slide switch goes between its switch-control terminal and GND (vendor's external-switch wiring)",
 "backfeed": "ideal_diode",
 "backfeed_part": "Adafruit 5830 LM66200 ideal-diode breakout (2.5 A, 40 mΩ) in place of the 1N5817",
 "backfeed_vdrop": 0.05,
 "erm_driver": "PN2222A",
 "erm_base_ohm": 470,
 "rtc_part": "PCF8523 (Adafruit 5189, CR1220 backup cell)",
 "rtc_vcc": 3.3,
 "ring_supply": "boost_5v",
 "ring_level_shift": "first_pixel",
 "icon_diode_vf": [
  0.6,
  0.85
 ],
 "boost_vout_tol": 0.04,
 "ring_data_pulldown_ohm": 10000,
 "mic_data_pulldown_ohm": 100000,
 "ring_brightness_cap": 0.3,
 "ring_fuse_A": 1.1,
 "ring_fuse_part": "Bourns MF-R110 (1.1 A hold / 2.2 A trip)",
 "main_fuse_A": 3.0,
 "main_fuse_part": "Bourns MF-R300 (3.0 A hold / 6.0 A trip) in the battery lead",
 "boost_in_cap_uF": 100,
 "cell_thermistor": "10 kΩ NTC on the cell (Adafruit 372, β 3950) on the charger's THERM pad (cut the THERM jumper)",
 "meeting_target_h": 3.0,
 "cell_mAh": 4000,
 "cell_part": "EREMIT 3.7 V 4000 mAh High Cap. (90 × 60 × 6 mm, 74 g, JST-PH, PCM: >4.25 V, <3 V, >1 C; 2 A continuous)",
 "charger": "bq24074",
 "charger_part": "Adafruit 4755 bq24074 USB/DC/Solar charger: power path, input limit set by its 1 kΩ ILIM resistor, OUT held at 4.4 V while USB is present, battery supplements above the limit",
 "usb_in_limit_A": [
  1.5,
  1.72
 ],
 "sys_on_usb_V": [
  4.3,
  4.5
 ],
 "charge_mA": 1000,
 "usb_source": "any USB-C phone charger: the tail port's 5.1 kΩ CC pull-downs (Adafruit 4090) ask a Type-C source for 5 V at up to 3 A; the device needs 1.5 A",
 "ambient_C": 25,
 "shell_max_C": 45,
 "meeting_floor_h": 2.0,
 "thermal_h_W_per_m2K": [
  11,
  14
 ],
 "thermal_free_area": 0.85,
 "heat_path": "SoC → thermal pad → 14 × 14 × 6 mm aluminium heatsink → two 8 W/mK pads → aluminium tape spreader inside the top shell (≈ 3 K/W from the chip to the shell): the whole shell sheds the heat. No fan: it would be recorded by the mics and needs vents"
}