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journal/stockcropper/SC Electronics Architecture.md
Thaddeus Hughes 608c43a71f init
2025-10-09 20:43:40 -05:00

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  1. MCU

Looks like the ESP32-WROOM-32 will work swimmingly. Pinout is as follows:

Peripheral Pin Assignment GPIO Number Notes/Functions
Analog Input 1 SENSOR_VP 36 ADC1_CH0, input-only
Analog Input 2 SENSOR_CAPP 37 ADC1_CH1, input-only
Analog Input 3 SENSOR_CAPN 38 ADC1_CH2, input-only
Analog Input 4 SENSOR_VN 39 ADC1_CH3, input-only
Digital Output 1 IO25 25 General I/O, output-capable
Digital Output 2 IO26 26 General I/O, output-capable
Digital Output 3 IO27 27 General I/O, output-capable
Digital Output 4 MTCK/IO13 13 General I/O, output-capable
Digital Output 5 MTMS/IO14 14 General I/O, output-capable
Digital Output 6 MTDO/IO15 15 General I/O, output-capable
Digital Input 1 VDET_1 34 General input, input-only
Digital Input 2 VDET_2 35 General input, input-only
I2C SDA IO21 21 I2C data, configurable
I2C SCL IO22 22 I2C clock, configurable
CAN TX IO4 4 TWAI TX, connects to transceiver TXD
CAN RX IO5 5 TWAI RX, connects to transceiver RXD
RTC Crystal XP 32K_XP 32 32.768 kHz crystal for RTC
RTC Crystal XN 32K_XN 33 32.768 kHz crystal for RTC

GPIO0, 2, 12, 16, 17, 18, 19, 23 are available for future expansion.

  1. CAN Bus

    1. Just need a 3.3V CAN Transceiver - SN65HVD231DR
    2. Connector - M12 bulkhead? BoardLock bulkhead?
      1. https://www.digikey.com/en/products/filter/circular-connectors/circular-connector-assemblies/436?s=N4IgjCBcoGwJxVAYygMwIYBsDOBTANCAPZQDaIAzABwUDscMIh1dcEAuoQA4AuUIAZR4AnAJYA7AOYgAvoXi1EIFJAw4CxMpQCscOFUXNdegCxMdeveYowADLe1Vrd2zAjMXMAEzP7MRh62YGBOgWBe7pR24WZhdL5g2toJdr5etoZRtukI8tq0XibJnCC8-EJiUrKEALQ%2B0MpQIgCuGiSQ5MUyciCMDaIAJvw1YEHmZZAg5jwAnly4-OjYKN1AA
      2. T4140012081-000 $13.09
      3. RTS712ND4S03 $15.97
      4. https://www.digikey.com/en/products/filter/circular-connector-assemblies/436?s=N4IgjCBcoGwJxVAYygMwIYBsDOBTANCAPZQDaIAzABwUDscMIhALGGFXLSALqEAOAFyggAygIBOASwB2AcxABfQgFpmiECkgYcBEADdpaLHkIlI5GOwo9%2BQyCEUqATOs0SArrrPkArDwVKIIzQIJIAJsLKYAAMELbCTCACAJ58uMLo2CgBQA
      5. 54-00216 $4.80 (4p male)
      6. 54-00235 $5.05 (4p female)
      7. I think we're gonna end up at M12 connectors for sensors and flying pigtails for motors

  2. Voltage Regulator

    1. Most of the time will be spent sleeping. A low quiescent current, then, is actually more important than live current, perhaps?
    2. TLV1117-33IDCYR would work but emits 4.35W at 500mA - thermals need looked into for this.
    3. TPS629210DRLR is also good. Just need 2 resistors and an inductor as well. Good cost. Probably better.
      1. 4.7 uF input cap
      2. 22 uF output cap
      3. 2.2 uH inductor - BDCD002520122R2MS1 (1008 case)

  3. RTC (use builtin to MCU)

    1. Need ext. osc: CM315D32768DZFT (2-SMD package)

  4. Jack Motor - 1 AI, 2 DO

    1. Motor: RP-785615
    2. Motor connector: AT06-2S
    3. Motor to cable connector: AT04-2P
    4. Cable: 16/2 PVC jacket cable
    5. Cable to Control Box: PG9 Cord Grip + Faston Tabs
    6. Relays (2): A161CS12VDC.64 (25A current, 53.3 mA coil)
    7. Relay driver: 2N7002AK-Q (240 mA max) (TO-236AB, TO-236-3, SC-59, SOT-23-3 package)
    8. Fuse: 20A ATO fuse
    9. Current sensor: ACS37042KLHBLT-030B3 (30A max, -030B5 exists which is a 5v variant)

  5. Fluffer (Accessory) Motor - 1 AI, 2 DO

    1. Motor: TBD
    2. Motor connector: AT06-2S
    3. Motor to cable connector: AT04-2P
    4. Cable: 16/2 PVC jacket cable
    5. Cable to Control Box: PG9 Cord Grip + Faston Tabs (1217861-1)
    6. Relays (2): A161CS12VDC.64 (25A current, 53.3 mA coil)
    7. Relay driver: 2N7002AK-Q (240 mA max)
    8. Fuse: 20A ATO fuse (3522-2 holder)
    9. Current sensor: ACS37042KLHBLT-030B3 (30A max, -030B5 exists which is a 5v variant) (SOT-23W)

  6. Drive Motor - 1 AI, 2 DO

    1. Motor: 80ZYT-12/JW-7 -OR- 80ZYT-12/JW-3B (50A)
    2. Motor connector: 6mm Ring Terminals with Boots
    3. Cable: 12/2 PVC jacket cable
    4. Cable to Control Box: PG9 Cord Grip + Faston Tabs
    5. Relays (2): A31CSP12VDC2 (70A current, 150 mA coil)
    6. Relay driver: 2N7002AK-Q (240 mA max)
    7. Fuse: No fuse, just the fuse/breaker for the main battery
    8. Current sensor: ACS37220LEZATR-100B3 (100A max, -100B5 exists which is a 5v variant) (7-PowerLQFN / 7-QFN)

  7. Jack Limit Switch - 1 DI

    1. Sensor: PBM6-AN-1H (-1A exists also which is a 2m pigtail. -1H is a M12 connector)

  8. Odometry Geartooth Sensor - 1 DI

    1. Sensor: PBM6-AN-1H (-1A exists also which is a 2m pigtail. -1H is a M12 connector)

  9. Solar Charging Circuit

    1. BQ24650 charge controller
    2. N-channel MOSFETs (Q1 high-side, Q2 low-side): 40V-rated, low RDS(on) (e.g., 20mΩ), such as AO3400 or equivalent, for synchronous rectification.
    3. Inductor (L): 10µH, rated for at least 5A saturation current (e.g., Wurth 7447788220) to support switching at 400kHz.
    4. Current sense resistor (R_SR): 10mΩ, 1% tolerance, 5W rating (e.g., WSMS5515L1000FEK) for ~4A maximum charge current (differential voltage of 40mV).
    5. Input capacitors: 10µF ceramic (X7R, 35V) × 3, placed near MOSFETs.
    6. Output capacitors: 4.7µF ceramic (X7R, 25V) × 2, near the battery connection.
    7. Schottky diodes: For reverse protection (e.g., 1N5819) and status indication.
    8. Resistors for voltage setting: Precision 1% types (e.g., R1 = 100kΩ, R2 = 576kΩ for 14.4V regulation).
    9. Optional: LEDs and resistors for charge status (e.g., bulk/absorption indication).

  10. Battery - 1 AI

    1. Battery: TL1212
    2. Battery to cable conn: Female Fastons
    3. Cable: 12/2 PVC jacket cable with fuseholder
    4. Cable to control box: PG9 Cord Grip + Faston Tabs
    5. Voltage divider to sense battery voltage (goes to ESP32) - 1M + 150k resistors

  11. Display

    1. Focus LCDs C162A-FTW-DS23 (-30 to +80C operating range)
    2. This will be driven by an I/O Expander. It could be shared with the buttons.
      1. 8 bit: PCF8574
      2. 16 bit: MCP23017 - pin 7 of each 8-bit bank can only be used as an output which is odd. or PCF8575 which is a little more $. Or best yet TCA9555PWR

  12. Settings Adjust Buttons (4 buttons)

    1. Option (SMD): TL3305BF260QG
    2. Option (THT): TS02-66-43-BK-260-SCR-D

  13. Manual Override Buttons (4 buttons)

    1. Option A: Hardwired, with an enclosed PCB
    2. Option B: Hardwired, with simple waterproof switches
    3. Option C: Remote
Pros of Remote Pros of Hardwire
Can operate from all around the coop Can't lose it
Easiest cable management Easy to repair
No pairing required
Easy interrupt (wake from sleep)
If you need to make it custom, it's easier
No batteries to die