SH-ESP32 Engine Top Hat

SH-ESP32 Engine Top Hat rendering

SH-ESP32 Engine Top Hat (Engine Hat) is an add-on board for the SH-ESP32. It allows you to measure common engine outputs:

  • Tachometer (RPM) senders, either using dedicated tach senders or alternator W terminals
  • Digital inputs such as engine alarms
  • Tank senders
  • Other resistive senders such as oil pressure senders with a resistance range of 0-300 ohm

The Engine Hat is a developer device. While example software is provided online, using the Engine Hat requires basic familiarity with working with sensors and microcontrollers.

See the Getting Started page for hardware installation and connection instructions.

The Hardware page contains more detailed information about the Engine Hat hardware.

The SH-ESP32 Engine Top Hat is open hardware and the design files can be found at the project GitHub repository. The product is available for purchase at


  • Compatible with SH-ESP32 (all versions)
  • 4 digital input channels (1-4)
    • input voltage range: -30V to +30V
    • threshold voltage: 1.65V
    • optional 1st order low-pass filter with cutoff frequency of 2.3 kHz
  • 4 analog input channels (A-D)
    • input voltage range: 0-29V
    • analog-to-digital converter: AD1115
    • ADC resolution: 16-bit
    • optional constant-current source with 10 mA current
    • resistance measurement range: 0-300 ohm

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