- Version
- System Diagram
- ESP32 DevKit V1
- LED Matrix
- Ambient Light Sensor
- Issues, Ideas And Bugs
- License
- Contribution
PCB board v1.5
| ESP32 DevKit V1 Pin | ESP32 DevKit V1 Pin Header | WROOM32 Pin | Notes | Usage |
|---|---|---|---|---|
| VIN | J1-1 | VIN | 5V power supply | Vcc (protected) |
| GND | J1-2 | GND | Ground | Ground |
| D13 | J1-3 | GPIO 13 | - | JTAG MTCK |
| D12 | J1-4 | GPIO 12 | Strapping pin; Fails if high at power-up, therefore not used. | JTAG MTDI |
| D14 | J1-5 | GPIO 14 | Output PWM at power-up! | JTAG MTMS |
| D27 | J1-6 | GPIO 27 | - | Data Out to LED matrix |
| D26 | J1-7 | GPIO 26 (A9) | - | - |
| D25 | J1-8 | GPIO 25 (A8) | - | - |
| D33 | J1-9 | GPIO 33 (A5) | - | 32.768 kHz crystal (32K_XN) |
| D32 | J1-10 | GPIO 32 (A4) | - | 32.768 kHz crystal (32K_XP) |
| D35 | J1-11 | GPIO 35 (A7) | Input only! See ESP32 tech. reference manual, chapter 4.1 (no internal pull-up/down circuitry) | - |
| D34 | J1-12 | GPIO 34 (A6) | Input only! See ESP32 tech. reference manual, chapter 4.1 (no internal pull-up/down circuitry) | LDR analog in |
| VN | J1-13 | GPIO 39 (VN) | Input only! See ESP32 tech. reference manual, chapter 4.1 (no internal pull-up/down circuitry) | - |
| VP | J1-14 | GPIO 36 (VP) | Input only! See ESP32 tech. reference manual, chapter 4.1 (no internal pull-up/down circuitry) | - |
| EN | J1-15 | EN | 10k Pull-Up; Button on ESP32 DevKit V1, closing to GND | USB RTS |
| VDD3V3 | J2-1 | VDD3V3 | 3.3 V output | 3.3 V output |
| GND | J2-2 | GND | Ground | Ground |
| D15 | J2-3 | GPIO 15 | Strapping pin | JTAG MTDO |
| D2 | J2-4 | GPIO 2 | Strapping pin; Onboard LED on ESP32 DevKit V1 | Onboard LED |
| D4 | J2-5 | GPIO 4 | - | User Button |
| RX2 | J2-6 | GPIO 16 (RX2) | - | - |
| TX2 | J2-7 | GPIO 17 (TX)2 | - | - |
| D5 | J2-8 | GPIO 5 | Strapping pin; 10k Pull-Up on ESP32 DevKit V1 | (DHT In) |
| D18 | J2-9 | GPIO 18 | - | - |
| D19 | J2-10 | GPIO 19 | - | - |
| D21 | J2-11 | GPIO 21 | - | I2C SDA (Arduino Standard) |
| RX0 | J2-12 | GPIO 3 (RX0) | - | USB RX |
| TX0 | J2-13 | GPIO 1 (TX0) | - | USB TX |
| D22 | J2-14 | GPIO 22 | - | I2C SCL (Arduino Standard) |
| D23 | J2-15 | GPIO 23 | - | Test Pin |
| - | - | GPIO 0 | Strapping pin, 10k Pull-Up; Button on ESP32 DevKit V1, closing to GND | USB DTR |
The following table shows the strapping bit status on the ESP32 DevKitV1 board. See also ESP32 series datasheet chapter 2.4
| Pin | Default | Function 1 | Function 2 |
|---|---|---|---|
| Voltage of internal LDO (VDD_SDIO) | |||
| Pin | Default | 3.3 V | 1.8 V |
| GPIO 12 (MTDI) | Low | Low | High |
| Result: 3.3 V |
| Pin | Default | Function 1 | Function 2 |
|---|---|---|---|
| Booting mode | |||
| Pin | Default | SPI Boot | Download Boot |
| GPIO 0 | High | High | Low |
| GPIO 2 | Low | Don't care | 0 |
| Result: SPI Boot |
| Pin | Default | Function 1 | Function 2 |
|---|---|---|---|
| Enabling/Disabling debugging log print over U0TXD during booting | |||
| Pin | Default | U0TXD Toggling | U0TXD Silent |
| GPIO 15 (MTDO) | High | High | Low |
| Result: U0TXD Toggling |
| Pin | Default | Function 1 | Function 2 | Function 3 | Function 4 |
|---|---|---|---|---|---|
| Timing of SDIO slave | |||||
| Pin | Default | Falling-edge Sampling | Falling-edge Sampling | Rising-edge Sampling | Rising-edge Sampling |
| GPIO 15 (MTDO) | High | Low | Low | High | High |
| GPIO 5 | High | Low | High | Low | High |
| Result: Rising-edge Sampling |
GPIOs 34 to 39 are input only pins. These pins don’t have internal pull-ups or pull-down resistors. They can’t be used as outputs, so use these pins only as inputs.
ADC2 is used by the Wi-Fi driver. Therefore the application can only use ADC2 when the Wi-Fi driver has not started. See Analog to Digital Converter.
| Pin | Function |
|---|---|
| MTDI (GPIO 12) | Test Data Input |
| MTCK (GPIO 13) | Test Clock |
| MTMS (GPIO 14) | Test Mode Select |
| MTDO (GPIO 15) | Test Data Output |
See ESP-PROG.
The LED matrix consists of 8 x 32 WS2812B LEDs. Each LED has a max. current of 60 mA, which would result in a max. power consumption of 5 V / 15.36 A. The flexible LED panel matrix would be damaged with this high nominal power consumption, therefore it shall be limited to 5 V / 4 A.
Input voltage level:
- High - Min. 0.7 * VDD
- => 0.7 * 5 V = 3.5 V
- Low - Max. 0.3 * VDD
- => 0.3 * 5 V = 1.5 V
The i/o pins of the ESP32 are running with a 3.3 V level, which could cause a problem in detection a high! Therefore the level must be shifted from 3.3 V to 5V.
The following table shows the output voltage, generated by a LDR like the GL5528 and a 1 k resistor. Both assembled as voltage divider.
| Ambient light | Ambient light | Photocell resistance | LDR + R | Voltage across R |
|---|---|---|---|---|
| Moonlit night | 1 lux | 70 kΩ | 71 kΩ | 0.046 V |
| Dark room | 10 lux | 10 kΩ | 11 kΩ | 0.3 V |
| Dark overcast day / Bright room | 100 lux | 1.5 kΩ | 2.5 kΩ | 1.32 V |
| Overcast day | 1000 lux | 300 Ω | 1.3 kΩ | 2.538 V |
| Full daylight | 10,000 lux | 100 Ω | 1.1 kΩ | 3.0 V |
If you have further ideas or you found some bugs, great! Create a issue or if you are able and willing to fix it by yourself, clone the repository and create a pull request.
The whole source code is published under the MIT license. Consider the different licenses of the used third party libraries too!
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, shall be licensed as above, without any additional terms or conditions.