Electonics building blocks


From Ali


Dumpster dive

  • DAGU robot MINI DC gearbox DG01D 48:1
  • Liyhium Poli Battery 3.7V 1300mAh
  • Qwiic motor driver (1.5 A peak drive per channel, 1.2 A steady state, Operates from 3 to 11 Volts with 12V absolute max, 3.3V default VCC and logic, Controllable by I2C or TTL UART signals) based on DRV8835. Similar chip I reveiwed already
  • Pi Servo Hat. 16 PWM channels, controllable over I2C
  • Accelerometer and gyroscope. I2C, 3.3V operating voltage
  • Passive Infrared (PIR) sensors are great for detecting motion in a small area around the sensor.
  • MicroMod MikroBUS Carrier Board - I also mention it in my power board development notes. equipped with a MCP73831 Single-Cell Lithium-Ion/Lithium-Polymer Charge IC. It receives power from the USB connection and can source up to 450mA to charge an attached battery. PLus 3.3V 1A Voltage

Other components


32-bit MCU (Xtensa LX7) from Espressif ESP32-S2-WROOM. Datasheet, hardware design guidelines. Not recommended for new designs (4/20/2024), that's why I got them from SparkFun with discount. To compare with Arduino Uno, ATMega328, or other boards: WROOM has 128 KB ROM, 320 KB SRAM Peripherals include 43 GPIOs, 1 full-speed USB OTG interface, SPI, I2S, UART, I2C, LED PWM, LCD interface, camera interface, ADC, DAC, touch sensor, temperature sensor.

Power from 3.7V battery ? 3.0V - 3.6V Wi-Fi (802.11 b/g/n) for communication About ADC. 2 ADC 10 channels each. ADC Attenuation Arduino IDE support. SPI for TFT display.

1.14 Inch TFT Display Module

  • Screen size: 135 x 240 (14.86 x 24.91 (mm))
  • Module size: 30.40 x 28 (mm)
  • Colors: 65K
  • Protocol: SPI
  • IC: ST7789V datasheet
  • VCC: 3.3V
  • store link
  • OLED ?

Connection (Wemos D1 R1)

  • GND -> GND obviously
  • VCC -> 3.3V
  • SCL -> D5 / SCK (clock)
  • SDA -> D7 / MOSI (data out)
  • RES -> D0 (reset, any port is good)
  • DC -> D3 (?, any port is good)
  • CS -> D4 (child select, any port is good)
  • BLK - not connected

1.44 inch TFT Display Module

  • Screen size: 240 x 240 (23.4 x 23.4 (mm))
  • Module size: 27,78 x 39.22 (mm)
  • Colors: 65K
  • Protocol: SPI
  • IC ST7789VW
  • VCC: 3.3V
  • store link
  • IPS ?


  • For Arduino boards do NOT forget resistors to make voltage dividers. Connecting to 3.3V pin is not enough to save the display from 5V.
  • Do not skip the Reset pin (-1 doesn't mean that it is not connected)

In order to avoid level shifting (voltage dividers) use 3.3V boards. Here are some options


number of columns and rows set in the config, and how SPI works

Artemis Dev Kit

  • pinout
  • About SPI (probably a typo in the pinout about SCK and SDO)

Vibration motors

  • Motor size: 4mm x 8mm
  • Rated voltage: 3.0V DC
  • Operating voltage range: 2.5-4.0V DC
  • Rotation direction: CW/CCW
  • Operating environment: -20°C - + 60°C
  • Storage Environment: -30°C - + 70°C
  • Rated speed: 11000 ± 3000RPM Min
  • Rated current: 90mA max
  • Stall current: 120mA max
  • Starting voltage: 2.4V DC Max
  • Insulation resistance: 10MΩ Min
  • Termination impedance: 30Ω ±15% (single phase) | | 60 Ω ±15% (duplex)
  • store link

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