Hotshoe-Mounted Light Meter
Alex Hao
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A portable light meter that mounts to the camera via hot shoe.
Many vintage film cameras don’t have built-in light meter, and eye-balling exposure can be very inaccurate.
User can set aperture and ISO, then the meter can display correct shutter speed.
Technical Overview
ESP32-S2-SOLO-U (w/o antenna)
Ambient light sensor and OLED display that talk via I2C
Powered by 105 mAh LiPo battery
Two rotary encoders with push buttons as input
Since film stocks have fixed ISO, it doesn’t need to be changed frequently
At the press of a button, ISO or Aperture setting can be locked to prevent accidentally changing it!
Base board
With buttons and knobs
Two-Piece shell for mounting and shielding for the light sensor
Mounted on the Leica MP film camera
Coming next version...
Smaller microcontroller (e.g. STM32)
USB charging functionality
Lower power consumption & longer battery life
Even more compact form factor
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