void setup(){}
void loop(){}

/*
  SEE ALSO
  https://www.expresspcb.com/pcb-cad-software/
  https://logicnet.dk/DiagramDesigner/
  https://www.circuit-diagram.org/
  https://ASCIIFLOW.COM
  https://TEXTIK.COM
*/

/*
           Attiny85 PINS (i2c)
                 ____
       RESET   -|*   |- 3V
       SCL (3) -|    |- (2)
       SDA (4) -|    |- (1)
       GND     -|____|- (0)

                 ____
     RESET PB5 -|*   |- VCC 3V
       ADC PB3 -|    |- PB2 ADC SCK
       ADC PB4 -|    |- PB1 PWM MISO
           GND -|____|- PB0 PWM MOSI AREF
*/

/*
         +----------------------------------------------------------------+
         |  1/PC6/PCINT14/RESET               D19/SCL/ADC5/PCINT13/PC5/28 |
         |  2/PD0/PCINT16/RXD/PD0/DIO00     DIO18/SDA/ADC4/PCINT12/PC4/27 |
         |  3/PD1/TXD/PCINT17/DIO01             DIO17/ADC3/PCINT11/PC3/26 |
         |  4/PD2/INT0/PCINT18/DIO02            DIO16/ADC2/PCINT10/PC2/25 |
         |~ 5/PD3/INT1/PCINT19/0C2B/DIO03       DIO15/ADC1/PCINT09/PC1/24 |
         |  6/PD4/T0/PCINT20/XCK/DIO04           DIO14/ADC0/PCINT8/PC0/23 |
         |  7/VCC                    ATmega328P                    GND/22 |
         |  8/GND       20mA/pin // 100mA/group // 200mA total    AREF/21 |
         |  9/PB6/OSC1/PCINT6/XTAL1                                VCC/20 |
         | 10/PB7/OXC2/PCINT7/XTAL2               DIO13/SCK/PCINT5/PB5/19 |
         |~11/PD5/T1/PCINT21/OC0B/DIO05          DIO12/MISO/PCINT4/PB4/18 |
         |~12/PD6/AIN0/PCINT22/OC0A/DIO06   DIO11/MOSI/PCINT3/OC2A/PB3/17~|
         | 13/PD7/AIN1/PCINT23/DIO07         DIO10/SS'/PCINT2/OC1B/PB2/16~|
         | 14/PB0/CLKO/PCINT0/ICP1/DIO08         DIO09/PCINT1/OC1A/PB1/15~|
         +----------------------------------------------------------------+
*/

/*
         +----------| USB |--------+
         | D13/SCK        MISO/D12 |
         | 3.3V           MOSI/D11~|
         | Vref             SS/D10~|
         | A0                   D9~|
         | A1       NANO        D8 |
         | A2                   D7 |
         | A3                   D6~|
         | A4/SDA               D5~|
         | A5/SCL               D4 |
         | A6              INT1/D3~|
         | A7              INT0/D2 |
         | 5V                  GND |
         | RST                 RST |
         | GND    5V DO  GND   TX1 |
         | Vin    DI SCK RST   RX1 |
         +-------------------------+
*/

/*
         +---|EXT|--------|USB|---+
         |    PWR          A5/SCL |
         |                 A4/SDA |
         |          UNO      AREF |
         |                    GND |
         | IOREF          SCK/D13 |
         | RST             DI/D12 |
         | 3V3             DO/D11~|
         | +5V                D10~|
         | GND                 D9~|
         | GND                 D8 |
         | Vin                 D7 |
         |                     D6~|
         | A0                  D5~|
         | A1                  D4 |
         | A2             INT1/D3 |
         | A3             INT0/D2~|
         | A4/DA  RS CK DI  TX>D1 |
         | A5/CL  GD D0 5V  RX<D0 |
         +------------------------+
*/

/*
         +-------|MICROUSB|-------+
         | J1 3V3/5V              | 
         | 21/TXD1      RAW 6~12V | 
         | 20/RXD1            GND |
         | GND  PRO MICRO   RESET |
         | GND  5mA MAX VCC/500mA |
         | 02/SDA         ADC4/A3 |
         | 03/SCL         ADC5/A2 |
         | 04/ADC08       ADC6/A1 |
         | 05/0C4A/0C3A   ADC7/A0 |
         | 06/ADC10        SCK/15 |
         | 07/AIN0        MISO/14 |
         | 08/ADC11       MOSI/16 |
         | 09/ADC12      ADC13/10 |
         +------------------------+
*/

/*
         +---|EXT|--------|USB|---+
         |    PWR  GD RS          |
         |         DO CK   SCL 21 |
         |         5V DI   SDA 20 |
         |                   AREF |
         |      MEGA2560      GND |
         |                    13~ |
         | IOREF              12~ |
         | RST                11~ |
         | 3v3                10~ |
         | +5V                09~ |
         | GND                08~ |
         | GND                    |
         | VIN                07~ |
         |                    06~ |
         | 54 A00             05~ |
         | 55 A01             04~ |
         | 56 A02             03~ |
         | 57 A03             02~ |
         | 58 A04         TX0 01~ |
         | 59 A05         RX0 00~ |
         | 60 A06                 |
         | 61 A07          TX3 14 |
         |                 RX3 15 |
         | 62 A08          TX2 16 |
         | 63 A09          RX2 17 |
         | 64 A10          TX1 18 |
         | 65 A11          RX1 19 |
         | 66 A12          SDA 20 |
         | 67 A13          SCL 21 |
         | 68 A14                 |
         | 69 A15                 |
         +------------------------+
           G55444  443333  322225
           D20864  208642  08642V
           ::::::  ::::::  ::::::
           G55444  443333  322225
           D31975  319753  19753v
*/

/*
         +--------|USB C|---------+
         |   [O]        [O]   GND |
         | CHGLED     RGBLED  SDA |
         |                    SCL |
         | +BAT OTEMP          CS |
         | -BAT               +5V |
         |        PORTENTA        |
         | AREF               +5V |
         | D15                VIN |
         | D16                3V3 |
         | D17                GND |
         | D18              RESET |
         | D19             TX/D14 |
         | D20             RX/D13 |
         | D21            SCL/D12 |
         |~D00            SDA/D11 |
         |~D01           CIPO/D10 |
         |~D02             CK/D09 |
         |~D03           COPI/D08 |
         |~D04             CS/D07 |
         |~D05                D06~|
         +------------------------+
*/

/*
         +------------+
         | GND  DHT22 |
         | SIG  DHT11 |
         | VCC        |
         +------------+
*/

/*
        +-------------+ 
        | 3V3     BMP |
        | GND    0X76 |
        | SDA         |
        | SCL   2.7mA |
        +-------------+
*/

/*
         +-------------------------+
         | GND              SDCARD |
         | 5V                      |
         | 3V3                     |
         | CS                      |
         | MOSI                    |
         | CLK                     |
         | MISO                    |
         +-------------------------+
*/

/*
         +---------|SDSLOT|--------+
         | +5V    ESP32CAM     3V3 |
         | GND      | O |       16 |
         | 12        CAM        00 |
         | 13                  GND |
         | 15           OUT/3V3/5V |
         | 14               RX0/03 |
         | 02               TX0/01 |
         | 04                  GND |
         |                   LED[] |
         +-------------------------+
*/

/*
         +---------|USBC|----------+
         | A/D0                 5V |
         | A/D1      XIAO      GND |
         | A/D2    ESP32C3     3v3 |
         | A/D3           MOSI/D10 |
         | D4/SDA         MISO/D09 |
         | D5/SCL          SCL/D08 |
         | D6/TX            RX/D07 |
         |   BOOT o       o  RESET |
         +-------------------------+
*/

/*
         +-------------------------+
         | EN       ESP32      D23 |
         | VP        DOIT      D22 |
         | VN       DEVKIT     TX0 |
         | D34                 RX0 |
         | D35                 D21 |
         | D32                 D19 |
         | D33                 D18 |
         | D25                 D05 |
         | D26                 TX2 |
         | D27                 RX2 |
         | D14                 D04 |
         | D12                 D02 |
         | D13                 D15 |
         | GND                 GND |
         | VIN                 3V3 |
         +-------------------------+
*/

/*
         +-------------------------+
         | 3V3      ESP32      GND |
         | EN               GPIO23 |
         | GPI36            GPIO22 |
         | GPI39            GPIO01 |
         | GPI35            GPIO03 |
         | GPIO32           GPIO21 |
         | GPIO33              GND |
         | GPIO25           GPIO19 |
         | GPIO26           GPIO18 |
         | GPIO27           GPIO05 |
         | GPIO14           GPIO17 |
         | GPIO12           GPIO16 |
         | GND              GPIO04 |
         | GPIO13           GPIO02 |
         | GPIO09           GPIO15 |
         | GPIO10           GPIO08 |
         | GPIO11           GPIO07 |
         | 5VDC             GPIO06 |
         +-------------------------+
*/

/*
           -----------------------
         /                         \
         | A0             WAKE/D00 |
         | N/C     ESP8266     D01~|
         | N/C            TXD1/D02~|
         | N/C                 D03~|
         | N/C                 D04~|
         | N/C                 3V3 |
         | N/C                 GND |
         | GND                 D05~|
         | 3V3                 D06~|
         | GND            RXD2/D07~|
         | 3V3            TXD2/D08~|
         | EN                 RXD0 |
         | RST                TXD0 |
         | GND                 GND |
         | +5V                 3V3 |
         +-------------------------+
*/

/*
                   VBAT ---+ +--- NTC
           ----------------+-+-----+
          /         NICLA      Vin |
         | A0/10    SENSE      N/C |
         | A1/11            VddOUT |
         | D09/CLK             GND |
         | D07/DI        LPIO3/D00 |
         | D08/DO     RX/LPIO2/D01 |
         | D06/CS     TX/LPIO1/D02 |
         | N/C            SCL1/D03 |
         | D05/LPIO0      SDA1/D04 |
         +-------------------------+
*/

/*
          +-----------+
          |ESP32 WeMos|
          |  D1 Mini  |       +------------+
          |RST      TX|       |POWER SUPPLY|
          |A8       RX|  +----|GND         |
          |D0       D1|  |-+--|5V          |
+-----CLK-|D5(14)   D2|  | |  +------------+
|         |D6       D3|  | |
| +--DATA-|D7(13)   D4|  | |
| | +--CS-|D8(15)    G|--+ |
| | |     |3V3      5V|--|-+  +-----------+
| | |     |           |  | |  |MAX7219 8x8|
| | |     |RESET      |  | +--|5V       5V|
| | |     +-----------+  +----|GND     GND|
| | +-------------------------|CS     DOUT|
| +---------------------------|DIN      CS|
+-----------------------------|CLK     CLK|
                              +-----------+
*/

/*
         +-------------------------+
LOW=DSBL | ENABLE    A4988    VMOT | 8-35vdc ---+ 100uf electro cap
         | MS1                 GND | gnd -------+ pwr spike protect
         | MS2                  2B | stepper 2B
         | MS3                  2A | stepper 2A
     SLP | RESET                1A | stepper 1A
     RST | SLEEP                1B | stepper 1B
 MCU pin | STEP                VDD | 5vdc
 MCU pin | DIR                 GND | gnd
         +-------------------------+

           * Library needs MOTOR TYPE
           https://www.airspayce.com/mikem/arduino/AccelStepper/classAccelStepper.html

           MS1	MS2	 MS3   Step resolution
           Low  Low	 Low   Full step
           High Low	 Low   1/2 step
           Low  High Low   1/4 step
           High High Low   1/8 step
           High High High  1/16 step

           SET DRIVER CURRENT LIMIT
           1. Power A4988 driver (Vdd, GND)
           2. Connect RST to SLP
           3. Disconnect motor
           4. Apply USB power
           5. Calculate current limit: Current Limit = Vref ÷ (8 × Rcs)
           6. A current limit of 1A (standard) needs Vref of 540mV
           7. Adjust POT while measuring Vref at GND to POT (metal screw)
           8. If the motor is making a lot of noise,  lower the current limit
*/

/*
          +-------------------------+ 
          |      [+][-] OUT1        |
          | +12vdc                  |
          | GND                     |
          | JMP+5v                  |
          | IN1              L298N  |
          | IN2                     |
          | IN3                     |
          | IN4                     |
          | JMP ENA/DIS             |
          |      [+][-] OUT2        |
          +-------------------------+
           ** AccelStepper.h needs MOTOR TYPE
           ** Coil sequence: motorPin1, motorPin3, motorPin2, motorPin4.
           https://www.airspayce.com/mikem/arduino/AccelStepper/classAccelStepper.html
*/

/*
          +-------------------------+ 
        1 | 1,2ENA          5v/VCC1 | 16
        2 | 1A      SN754410     4A | 15
        3 | 1Y                   4Y | 14
        4 | <---- GND/HEATSINK ---->| 13
        5 | <---- GND/HEATSINK ---->| 12
        6 | 2Y                   3Y | 11
        7 | 2A                   3A | 10
        8 | VCC2 (4.5V-36V)   3,4EN | 9
          +-------------------------+ 
          <1:4>A 2, 7, 10, 15 I Driver inputs, non-inverting
          <1:4>Y 3, 6, 11, 14 O Driver outputs (1 amp max)
*/

/*
          +-------------------------+
      VCC | 1       MAX7219      16 | VDD
      GND | 2                    15 | GND
      DIN | 3 -->            --> 14 | DOUT
       CS | 4                    13 | CS
      CLK | 5                    12 | CLK
          +-------------------------+
*/

/*
           +-------------------------+
     ANODE+| 1 -+    PC817X     |/-3 | EMITTER
           |    v     OPTO      |    | 
           |   ===  COUPLER     |    | 
   CATHODE-| 2 -+               |\-4 | COLLECTOR
           +-------------------------+
*/

/*
         LCD1602
     PIN 12 - LCD RS
     PIN 11 - LCD EN
     PIN 05 - LCD D4
     PIN 04 - LCD D5
     PIN 03 - LCD D6
     PIN 02 - LCD D7
        GND - LCD R/W
        GND - LCD VSS
        +5V - LCD VCC
 5V/r220OHM - LCD LED+
        GND - LCD LED-

            10k potentiometer to +5V and GND, with it's wiper (output) to LCD VO pin (pin3).
*/

/*
           *-------------------------+
 REF/AIN11 | 1      MAX11614      16 | VDD
     AIN10 | 2      MAX11617      15 | GND
     AIN09 | 3                    14 | SDA
     AIN08 | 4                    13 | SCL
     AIN00 | 5                    12 | AIN07
     AIN01 | 6                    11 | AIN06
     AIN02 | 7                    10 | AIN05
     AIN03 | 8                     9 | AIN04
           +-------------------------+
*/

/*
           +-------------------------+ 
           |[o] ANT           LED[o] |
           | NET   SIM800L V1        |
           | VCC (3.4-4.4V@2A)  RING |
           | RST                 DTR |
           | RXD                MIC+ |
           | TXD                MIC- |
           | GND                SPK+ |
           |                    SPK- |
           +-------------------------+
*/

/*
           +---------------------------+ 
           | [o]ANT [L]D6NET [L]D2RING |
           | 5VIN PWR                  |
           | GND PWR        SIM800L V2 |
           | VDD TTL                   |
           | TXD                       |
           | RXD      D6 @ 1S pwr      |
           | GND TTL  D6 @ 3S reg'd    |
           | RST                       |
           +---------------------------+
*/

/*
                       V G
           +----------|C-N|-----------+ 
           |           C D            |
           |       VCC o o GND [o] ANT|
           |       5TX o o 5RX (5v)   |
           |       3TX o o 3TX (3V3)  |
           |            +-----------+ |
           |            |           | |
           |            |  SIM900A  | |
           |            |           | |
           |            +-----------+ |
           +--------------------------+
*/

/*
           +-------------------------+ 
           | GND      ROTARY ENCODER |
           | VCC                     |
           | SWITCH (PRESS = LOW)    |
           | DATA  (OUTB)            |
           | CLOCK (OUTA)            |
           +-------------------------+
*/

/*
           +-------------------------+ 
           | GND            JOYSTICK |
           | VIN                     |
           | VRX/XPOS                |
           | VRY/YPOS                |
           | SW                      |
           +-------------------------+
*/

/*
           +-------------------------+ 
           | VIN              BH1750 |
           | GND              Light  |
           | SCL              Sensor |
           | SDA                     |
           | ADDR                    |
           +-------------------------+
*/

/*
  WS2812B - VCC - 1000uF ECAP(+)        - Arduino VIN - Power supply (+)
          - SIG - 300-500 Ohm resistor  - Arduino SIG - x
          - GND - 1000uF ECAP(-)        - Arduino GND - Power supply (-)

         +----------| USB |--------+       +-----+
         | D13/SCK        MISO/D12 |       |E.CAP|
         | 3.3V           MOSI/D11~|       |1k uF|
         | Vref             SS/D10~|       +-----+
         | A0                   D9~|      -|     |+        +--------------+
         | A1       NANO        D8 |  +----|-----+---------| VCC          |
         | A2                   D7 |  | +--+---------------| GND          |
         | A3                   D6~|--|-|-----|470R Ohm|---| SIG  WS2812B |
         | A4/SDA               D5~|  | |                  +--------------+
         | A5/SCL               D4 |  | |
         | A6              INT1/D3~|  | |   +--------+
         | A7              INT0/D2 |--|-|---| BUTTON |
         | 5V                  GND |--|-|---|        |=|
         | RST                 RST |  | |   +--------+
    +----| GND    5V DO  GND   TX1 |  | |
    | +--| Vin    DI SCK RST   RX1 |  | |   +--------------+
    | |  +-------------------------+  | |   | POWER SUPPLY |
    | +-------------------------------+-|---| VCC          |====||= MAINS
    +-----------------------------------+---| GND          |
                                            +--------------+
*/

/*
  https://circuitdigest.com/microcontroller-projects/arduino-color-sorter-machine-using-tcs3200-color-sensor
  https://www.youtube.com/watch?v=1qr6v4YTz38&t=1s

  +----------------------------------------+
  | +------------------------------------+ |
  | |  ===========                       | |
  | | | ARDUINO  |            =======    | |
  | | |          |     SERVO |DROPsrv|   | |
  | | |       D10|->---------|PWM GND|---+ |
  | | |          |           |    +5V|---|-+
  | | |          |            =======    | |
  | +-| 5V       |     SERVO |PICKsrv|   | |
  +---|GND    D09|->---------|PWM GND|---+ |
      |          |           |    +5V|---|-+
      |          |            =======    | |
      |          |         +-------------|-+
      |          |         |  =========  |
      |          |         | | TSC3200 | |
      |          |         +-|VCC   GND|-+
      |       D08|-----------|OUT    OE|-+
      |       D07|->---------|S2     S1|---+
      |       D06|->---------|S3     S0|-+ |
      |          |            =========  | |
      |       D05|->---------------------|-+
      |       D04|->---------------------+
      ============

      TSC3200
      S0 S1 OUTPUT FREQUENCY SCALING
      L  L  Power down
      L  H  2%
      H  L  20%
      H  H  100% 

      S2 S3 PHOTODIODE
      L  L  RED
      L  H  BLU
      H  L  CLR (no filter)
      H  H  GRN
*/

/*
    +--------------------------------------+
    | +----------------------------------+ |
    | |                                  | |    +-------------+
    | |  +---------| USB |---------+     +-|----| SCK  SDCARD |
    | +--| D13/SCK        MISO/D12 |-------|----| MISO        |
    +----| 3.3V           MOSI/D11~|-------|----| MOSI        |
         | Vref             SS/D10~|  +----|----| CS          |
         | A0                   D9~|  |    +----| 3V3         |
         | A1       NANO        D8 |  |  +-+----| GND         | 
         | A2                   D7 |  |  | |    | 5V          |
         | A3                   D6~|  |  | |    +-------------+
+--------| A4/SDA               D5~|--+  | |    +-------------+
| +------| A5/SCL               D4 |     | | +--| VCC   DHT22 |
| |      | A6              INT1/D3~|-----|-|-|--| SIG         |
| |      | A7              INT0/D2 |--+  +-|-|--| GND         |
| | +----| 5V                  GND |--|--+ | |  +-------------+
| | |    | RST                 RST |  |  | | |      +-------------+
| | | +--| GND    5V DO  GND   TX1 |  +--|-|-|------| SQW  DS3231 |
| | | |  | Vin    DI SCK RST   RX1 |     | +-|------| 3V3         |
| | | |  +-------------------------+     | | | +----| SDA         |
| | +-|----------------------------------|-|-+ | +--| SCL         |
| |   +----------------------------------+-|---|-|--| GND         |
| |   |                                    |   | |  +-------------+
| |   |                                    |   | |  +-------------+
| |   |                                    +---|-|--| 3V3     BMP |
| |   +----------------------------------------|-|--| GND    0X76 |
| +--------------------------------------------|-+--| SCL         |
+----------------------------------------------+----| SDA   2.7mA |
                                                    +-------------+
*/

/*
  https://forum.arduino.cc/t/im-not-sure-if-i-connected-all-the-components-correctly/1109715/8

         +---|EXT|--------|USB|---+                    
         |    PWR          A5/SCL |
         |                 A4/SDA | 
         |          UNO      AREF | 
         |                    GND |          ==o===>
         | IOREF          SCK/D13 |        +---|---+
         | RST             DI/D12 |        |SERVO 1|
         | 3V3             DO/D11~|        |    GND|---+
         | +5V                D10~|   +----|SIG VCC|---|-+
         | GND                 D9~|---+    +-------+   | |
   +-----| GND             KEY D8 |------------------+ | |
   |  +--| Vin                 D7 |                  | | |
   |  |  |                     D6~|        +-------+ | | |
   |  |  | A0                  D5~|        | HC-05 | | | |  +---------+   +------+
   |  |  | A1                  D4 |    +---|RXD GND|-|-+ |  |  BUCK   |   |POWER |
   |  |  | A2             INT1/D3 |----+ +-|TXD VCC|-|-|-+  |CONVERTER|   |SUPPLY|
   |  |  | A3             INT0/D2~|-R1k+   |STA KEY|-+ | +--|OUT+  IN+|---|+V    |
   |  |  | A4/DA  RS CK DI  TX>D1 |    |   +-------+   +-|--|OUT-  IN-|---|-V    |===(mains)===|=
   |  |  | A5/CL  GD D0 5V  RX<D0 |    +---R2k-+       | |  +---------+   +------+
   |  |  +------------------------+      RX=3v3|Vdiv   | |
   +--|----------------------------------------+-------+ | * some HC05 need Vdiv for 3v3 data
      +--------------------------------------------------+
*/

/*
    https://forum.arduino.cc/t/arduino-lcd-display-issue/1110217/5
    
     +-------------------------------------------------------+
     |                  +----------+                         |
     |                  |My_LCD1 RS|-------------------------+
     |                  |        EN|-------------------------+
     |                  |        D4|----------------------+  |
     |                  |        D5|--------------------+ |  |
     |                  |        D6|------------------+ | |  |
     |                  |        D7|----------------+ | | |  |
     |                  +----------+                | | | |  |
     |                  +----------+                | | | |  |
     |                  |My_LCD2 RS|-------------+  | | | |  |
     |                  |        EN|-----------+ |  | | | |  |
     |                  |   (D7) D4|---------+ | |  | | | |  |
     |                  |   (D8) D5|-------+ | | |  | | | |  |    +----------+
     |                  |   (D9) D6|-----+ | | | |  | | | |  |    | DHT2 VCC |----+
     |                  |  (D10) D7|---+ | | | | |  | | | |  |    |      GND |--+ |
     |                  +----------+   | | | | | |  | | | |  | +--| SIG      |  | |
     |                                 | | | | | |  | | | |  | |  +----------+  | |
     |   +----------| USB |--------+   | | | | | |  | | | |  | |                | |
     +---| D13/SCK        MISO/D12 |---|-|-|-|-|-|--|-|-|-|--|-+                | |
         | 3.3V           MOSI/D11~|---|-|-|-|-|-|--|-|-|-|--|-+                | |
         | Vref             SS/D10~|---+ | | | | |  | | | |  | |  +----------+  | |
         | A0                   D9~|-----+ | | | |  | | | |  | |  | DHT1 VCC |--|-+
         | A1       NANO        D8 |-------+ | | |  | | | |  | |  |      GND |--+ |
         | A2                   D7 |---------+ | |  | | | |  | +--+ SIG      |  | |
         | A3                   D6~|-----------|-|--+ | | |  |    +----------+  | |
         | A4/SDA               D5~|-----------|-|----+ | |  |                  | |
         | A5/SCL               D4 |-----------|-|------+ |  |                  | |
         | A6              INT1/D3~|-----------|-|--------+  |                  | |
         | A7              INT0/D2 |-----------|-+           |                  | |
   +-----| 5V                  GND |           |             |                  | |
   |     | RST                 RST |           |             |                  | |
   | +---| GND    5V DO  GND   TX1 |           |             |                  | |
   | |   | Vin    DI SCK RST   RX1 |-----------+-------------+                  | |
   | |   +-------------------------+                                            | |
   | +--------------------------------------------------------------------------+ |
   +------------------------------------------------------------------------------+
*/

/*
  https://forum.arduino.cc/t/loadcell-as-a-switch/1112944

               +---|EXT|--------|USB|---+        +------------------+
               |    PWR          A5/SCL |        | 12v POWER SUPPLY |
               |                 A4/SDA |       +|(mains+)     +12V |----+
               |          UNO      AREF |       -|(mains-)      GND |--+ |
               |                    GND |        +------------------+  | |
               | IOREF          SCK/D13 |                              | |
               | RST             DI/D12 |            +--------------+  | |
               | 3V3             DO/D11~|            |BUCK CONVERTER|  | |
          +----| +5V                D10~|        +---|OUT+5v  12vIN+|--|-+
          |    | GND                 D9~|        | +-|OUT-5v  12vIN-|--+-|
          | +--| GND                 D8 |------+ | | +--------------+  | |
          | |  | Vin                 D7 |      | | |                   | |
          | |  |                     D6~|      | | |                   | |
          | |  | A0                  D5~|----+ | | | +-----------+     | |
          | |  | A1                  D4 |--+ | | | | |   RELAY   |     | |
          | |  | A2             INT1/D3 |  | | | | +-| DC-    NC |     | |
          | |  | A3             INT0/D2~|  | | | +---| DC+   COM |-----|-+
          | |  | A4/DA  RS CK DI  TX>D1 |  | | +-----| DIN    NO |-----|-+
          | |  | A5/CL  GD D0 5V  RX<D0 |  | |       +-----------+     | |
          | |  +------------------------+  | |                         | |
          | +------------------------------|-|-+     +-----------+     | |
          |    +------------------------+  | | |     |      +12V |-----|-+
 +--------|----| E+ RED    HX711        |  | | |     | FAN   GND |-----+
 | +------|----| E- BLK  AMPLIFIER      |  | | |     +-----------+
 | | +----|----| A- WHT             GND |--|-|-+
 | | | +--|----| A+ GRN            DOUT |--+ | ** HX711 is not I2C but Sync Serial. Use other DIN pins.
 | | | |  |    | B-    (E) Excite   SCK |----+ ** HX711 is not I2C but Sync Serial. Use other DIN pins.
 | | | |  |    | B+  (A/B) Output   VCC |--------+
 | | | |  |    +------------------------+        |
 | | | |  +--------------------------------------+
 | | | |       +--------------------------------------------+
 | | | +-------| RED EX+     EX+ ----/\               HX711 |
 | | +---------| BLK EX-    SIG+ ___/  \___ SIG-  LOAD CELL |
 | +-----------| WHT SIG-           \  /                    |
 +-------------| GRN SIG+            \/____  EX-            |
               +--------------------------------------------+
               https://github.com/bogde/HX711/blob/master/examples/HX711_basic_example/HX711_basic_example.ino
*/

/*
  https://forum.arduino.cc/t/problems-with-esp-and-led-matrix/1117999
           -----------------------
         /                         \
         | A0             WAKE/D00 |
         | N/C     ESP8266     D01~|
         | N/C            TXD1/D02~|
         | N/C                 D03~|
         | N/C                 D04~|
         | N/C                 3V3 |
         | N/C                 GND |
         | GND                 D05~|
         | 3V3                 D06~|
         | GND            RXD2/D07~|
         | 3V3            TXD2/D08~|
         | EN                 RXD0 |
         | RST                TXD0 |
         | GND                 GND |
         | +5V                 3V3 |
         +-------------------------+

         +-------------------------+
     VCC | 1       MAX7219      16 | VDD
     GND | 2                    15 | GND
     DIN | 3 -->            --> 14 | DOUT
      CS | 4                    13 | CS
     CLK | 5                    12 | CLK
         +-------------------------+

   |  |  +--------------+
   |  |  |BUCK CONVERTER|
   |  +--|OUT+       IN+|---(EXT+V)
   +-----|OUT-       IN-|---(EXT-V)
         +--------------+
*/

/*
  +--------------------------------------------------------+---------------+
  | +-----------------------------------+----------------+ |               |
  | |                                   |                | |               |
  | |   +---|EXT|--------|USB|---+      |                V G               |
  | |   |    PWR          A5/SCL |      |                C N               |
  | |   |                 A4/SDA |      |    +----------|C-D|-----------+  |
  | |   |          UNO      AREF |      |    |                   [o]ANT |  |
  | |   |                    GND |      +----|-----+ VCC o o GND +------|--+
  | |   | IOREF          SCK/D13 |      +----|-----+ 5TX o o 5RX (5v) +-|--+
  | |   | RST             DI/D12 |      |    |       3TX o o 3TX (3V3)  |  |
  | |   | 3V3             DO/D11~|      |    |            +-----------+ |  |
  | +---| +5V                D10~|      |    |            |           | |  |
  |     | GND                 D9~|      |    |            |  SIM900A  | |  |
  +-----| GND                 D8 |      |    |            |           | |  |
        | Vin                 D7 |      |    |            +-----------+ |  |
        |                     D6~|      |    +--------------------------+  |
        | A0                  D5~|      |                                  |
        | A1                  D4 |      |                                  |
        | A2             INT1/D3 |--RX--+                                  |
        | A3             INT0/D2~|--TX-------------------------------------+
        | A4/DA  RS CK DI  TX>D1 |
        | A5/CL  GD D0 5V  RX<D0 |
        +------------------------+
*/

/*
https://forum.arduino.cc/t/please-review-this-circuit-diagram/1098338

                                --------
  +-------------------+         |MOTOR |
  |         --------- |         |DRIVER|
  |         |ESP32CM| |         |HG7881|   -------
  | +-------|+5V 3V3| |         | OUT1+|---|LEFT |
  | | +-----|GND  16|-+         | OUT1-|---|WHEEL|
  | | |     |     00|  +--------|A-1A  |   -------
  | | |     |12     |  | +------|A-1B  |   -------
  | | |     |13  GND|  | |      | OUT2+|---|RIGHT|
  | | |   +-|15  VCC|  | |      | OUT2-|---|WHEEL|
  | | | +-|-|14     |  | | +----|IN+   |   ------
  | | | | | |     03|--+ | | +--|IN-   |   ------
  | | | | | |02   01|----+ | |  | OUT3+|---|5VDC|
  | | | | | |04  GND|      | |  | OUT3-|---|PUMP|
  | | | | | ---------      | |  --------   ------
  | | | | |                | |
  | | | | +----------------|-|-----------------------+
  | | | +------------------|-|---------------------+ |
  | | +--------------------|-+---------+           | |
  | +-|--------------------+---------+ |           | |
  | | |     --------     --------    | |   ------- | |
  | | |     |POWER |     | BUCK |    +-|---|SERVO|-+ |
  | | |     |SUPPLY|     |CONVRT|    | +---|  0  |   |
  | | |     |7.4vdc|---->| 5VDC |----+ |   -------   |
  | | |     | GND  |---->| GND  |----|-+             |
  | | |     -------      --------    | |   -------   |
  | | |                  --------    | +---|SERVO|---+
  | | |                  | FIRE |    +-----|  1  |
  | | |                  |SENSOR|          -------
  | +-|------------------|GND   |
  |   +------------------|VCC   |
  +----------------------|SIGNAL|
                         --------
*/

/*
  +-------------------------+
  |         FEATHER         |
  |SDA                    37|
  |SCL                    TX|
  |14                     RX|       ---------
  |32                     MI|       |  P.S. |
+-|15                     MO|  +----|VCC HOT|--+
| |33                    SCK|  |  +-|GND GND|--|------------+
| |27                     A5|  |  | ---------  |            |
| |12                     A4|  |  |            |            |
| |13                     A3|  |  | ---------  | ---------  |
| |USB                    A2|  |  | | RELAY |  | | MAINS |  |
| |EN                     A1|  +--|-|VCC    |  +-|HOT GND|--+
| |BAT                    A0|  +--|-|IN   NC|  | ---------  |
| |                      GND|--|--+-|GND COM|<-+            |
| |                         |  |    |     NO|>----->BULB<---+
| |                       3V|  |    ---------
| |                      RST|  |
| --------------------------+  |
+------------------------------+
*/

/*
https://forum.arduino.cc/t/sensors-not-working-together-bmp280-neo6m-sdcard/1091656

Arduino - 500 mA max

BMP280 (GND-GND, Vcc-3.3V, SCL-A5, SDA-A4)
NEO 6M (Vcc-5V, Rx-D6, Tx-D5, GND-GND)
SD Card (GND-GND, Vcc-5V, MISO-D12, MOSI-D11, SCK-D13, CS-D10)


        +------------------+
        |   -------------  |  -------
------- |   |    UNO    |  |  | SD  |
| BMP | |   |   200ma   |  |  |200mA|
|2.7mA| |   |           |  +--| Vcc |
| Vcc |-|---| 3v3   GND |-----| GND |
|     | +---| +5v    13 |-----| SCK |
| GND |-|-+-| GND    12 |-----| MIS |
|     | | | |        11 |-----| MOS |
|0X76 | | | | A00    10 |-----| CS  |
|     | | | | A01       |     -------
| SDI |-|-|-| A04       |     -------
| SCK |-|-|-| A05       |     | GPS |
|     | | | |           |     |10mA |
------- | | |        D6 |-----|  RX |
        | | |        D5 |-----|  TX |
        | | -------------     |     |
        | +-------------------| GND |
        +---------------------| Vcc |
                              -------
*/

/*
     A     B     C    D
  +-----+-----+-----+-----+
  |   x-|---x-|---x-|---x-|--1
1 |  A1 |  B1 |  C1 |  D1 |
  | y   | y   | y   | y   |
  +-|---+-|---+-|---+-|---+
  | | x-|-|-x-|-|-x-|--x--|--2
2 | |A2 | |B2 | |C2 | |D2 |
  | y   | y   | y   | y   |
  +-----+-----+-----+-----+
  | | x-|-|-x-|-|-x-|--x--|--3
3 | |A3 | |B3 | |C3 | |D3 |
  | y   | y   | y   | Y   |
  +-----+-----+-----+-----+
  | | x-|-|-x-|-|-x-|--x--|--5
4 | |A4 | |B4 | |C4 | |D4 |
  | y   | y   | y   | y   |
  +-----+-----+-----+-----+
  | | x-|-|-x-|-|-x-|--x--|--5
5 | |A5 | |B5 | |C5 | |D5 |
  | y   | y   | y   | y   |
  +-|---+-|---+-|---+-|---+
    |     |     |     |
    A     B     C     D

if (A1x && A1y)
	light A1
if (A2x && A2y)
.	light A2
.
.
if (D5x && D5y)
	light D5
*/

/*
ANALOG INPUT	WIRED TO	CLOSED	OPEN
no pullup/down 	GND		0		random
no pullup/down	Vcc		1		random
WITH pullup		either	0		1
with pullDOWN	either	1		0
*/

/*
https://forum.arduino.cc/t/stepper-motor-with-opto-coupler-on-analog-pin-2-forward-and-reverse/1080859/

                    --------
         --------   |MOTOR |
         | NANO |   |DRIVER|
         |  D08 |-->| IN1  |
         |  D09 |-->| IN2  |
         |  D10 |-->| IN3  |
         |  D11 |-->| IN4  |
  +---->>| A02  |   |      |
  | +----| GND  |   |      |
  | | +--| VIN  |   |L398N |
  | | |  --------   |      |
  ^ | |  --------   |      |
  ^ | |  |MOTOR |   |      |
  | | |  | INA+ |<--| OUT1 |
  | | |  | INA- |<--| OUT2 |
  | | |  | INB+ |<--| OUT3 |
  | | |  | INB- |<--| OUT4 |
  | | |  --------   |      |
  | | |  --------   |      |
  | | |  |POWER |   |      |
  | | |  |SUPpLY|   |      |
  | | +--| +5V  |---| 5VDC |
  | | |  |      |   |      |
  | +-|--| GND  |---| GND  |
  | | |  -------    --------
  | | |             --------
  | | |             |H21A1 |
  | | |             |SENSOR|
  | +-|-------------|3-LED |
  | | |             |      |
  | | +-------------|1+LED |
  ^ |               |      |
  ^ +----RES 100----|2-XSTR|
  | |               |      |
  +-+-<<-RES-1k-<<--|4+XSTR|
                    --------
*/

/*
                                                   +------------------------+            +------------------------+
           +-------------------------+        +----| 1 -+ ANODE    EMIT|/>3 |------------| DIM+   MEANWELL        |
           | EN    ESP32    MOSI D23 |        |    |    v    PC817X    |    |       +----| ACL     HLG240H        |
           | VP    DEVKIT    SCL D22 |------+ |    |   === OPTOCOUPLER |    |       | +--| ACN                Vo+ |-----+
           | VN              TX0 TX0 |  +---|-|----| 2 -+ CAT     COLL |\-4 |-------|-|--| DIM-               Vo- |---+ |
           | D34                 RX0 |  |   | 2    +------------------------+       | |  +------------------------+   | |
           | D35             SDA D21 |--|-+ | 2    +-------------------------+      | |  +------------------------+   | |
      +----| D32 PWM             D19 |  | | | 0    | WALL POWER          ACL |----+ | |  |    LED lighting        |   | |
      | +--| D33 PWM             D18 |  | | | R    |                     ACN |--+-|-|-+  |                      + |---+ |
      | |  | D25                 D05 |  | | | E    +-------------------------+  | | |    |                      - |-----+
      | |  | D26                 TX2 |  | | | S    +-------------------------+  | | |    +------------------------+
      | |  | D27                 RX2 |  | | | I    | 5V      RELAY       GND |--+ | |
      | |  | D14                 D04 |  | | | S    | GND                 COM |----+ |
      | |  | D12                 D02 |  | | | T +--| DIN                 N.O.|------+
      | |  | D13                 D15 |  | | | O |  +-------------------------+
      | |  | GND                 GND |--+ | | R |  +-------------------------+
      | |  | VIN                 3V3 |--|-|-|-|-|--| VIN              BH1750 |
      | |  +-------------------------+  +-|-|-|-|--| GND              Light  |
      | |                                 | +-|-|--| SCL              Sensor |
      | |                                 +---|-|--| SDA                     |
      | +-------------------------------------+ |  | ADDR                    |
      +-----------------------------------------+  +-------------------------+
*/

/*
               +---|EXT|--------|USB|---+           +--------------+        +------------------+
               |    PWR          A5/SCL |           |BUCK CONVERTER|        | 12v POWER SUPPLY |
               |                 A4/SDA |     +-----|OUT+5v  12vIN+|--+-----|+12V      (mains+)|
               |          UNO      AREF |     | +---|OUT-5v  12vIN-|--|--+--|GND       (mains-)|
               |                    GND |     | |   +--------------+  |  |  +------------------+
               | IOREF          SCK/D13 |     | |                     |  |                
               | RST             DI/D12 |     | |   +-----------+     |  |            ___,
               | 3V3             DO/D11~|     | |   |   RELAY   |     |  |           ' |
          +----| +5V                D10~|     | +---| DC-    NC |     |  |   +---------'--------+
          |    | GND                 D9~|-+   +-|---| DC+   COM |--<<-+  +---| GND          FAN |
          | +--| GND                 D8 |-|-+-|-|---| DIN    NO |-->>--------| +12V             |
          | |  | Vin                 D7 | | | | |   +-----------+            +------------------+
          | |  |                     D6~| | | | |
          | |  | A0                  D5~| | | | |                           +-----+
          | |  | A1                  D4 | | | +-|---------------------------|-LED |
          | |  | A2             INT1/D3 | | +-|-|---------------------------|+LED |
          | |  | A3             INT0/D2~| |   | |     +------------+        +-----+
     +----| |  | A4/DA  RS CK DI  TX>D1 | |   | +-----| GND  DHT22 |
     | +--|-|--| A5/CL  GD D0 5V  RX<D0 | +---|-|-----| SIG        |
     | |  | |  +------------------------+     +-|-----| VCC        |
     | |  | +---------------------------------+ |     +------------+
     | |  +-----------------------------------|-+
     | |       +------------------------+     | |
     | +-------| CLK    LCD 1602    VCC |-----+ |
     +---------| SDA                GND |-------+
               +------------------------+

      L9110 motor driver:
      https://cdn-shop.adafruit.com/product-files/4489/4489_datasheet-l9110.pdf
*/

/*
            +---|EXT|--------|USB|---+
            |    PWR          A5/SCL |
            |                 A4/SDA |
            |          UNO      AREF |
            |                    GND |            +-----+
            | IOREF          SCK/D13 |            |SERVO|       
            | RST             DI/D12 |            | GND |-------+
            | 3V3             DO/D11~|----+       | VCC |-----+ |
      +-----| +5V                D10~|  +-|-------| SIG |     | |
      |     | GND                 D9~|--+ |       +-----+     | |
    +-|-----| GND                 D8 |--+ |   +------------+  | |
  +-|-|-----| Vin                 D7 |  | +---| ENB  L298N |  | |
  | | |     |                     D6~|--|-----| ENA        |  | |
  | | |     | A0                  D5~|--|-----| IN1     5V |--+ |
  | | |     | A1                  D4 |--|-----| IN2    GND |--|-+
  | | |     | A2             INT1/D3 |--|-----| IN4        |  | |
  | | |     | A3             INT0/D2~|--|-----| IN3        |  | |
  | | | +---| A4/DA  RS CK DI  TX>D1 |  |     +------------+  | |
  | | | | +-| A5/CL  GD D0 5V  RX<D0 |  |     +------------+  | |
  | | | | | +------------------------+  +-----| SIG  FLAME |  | |
  | +-|-|-|-----------------------------------| GND SENSOR |  | |
  | | +-|-|-----------------------------------| VCC        |  | |
  | |   | |  +---------+                      +------------+  | |
  +-|---|-|--| 9V  PDB |                                      | |
    +---|-|--| GND     |                      +------------+  | |
        | |  +---------+                      |  MLX90614  |  | |
        | +-----------------------------------| SCL    VCC |--+ |
        +-------------------------------------| SDA    GND |----+
                                              +------------+
             

*/