Amazon.com : Pixel Hotshoe Adapter with Pc Port for Sony A7 A7S A7SII A7R A7RII A7II NEX6 RX1 RX1R RX10 RX100II HX50 A6000 A6300 to Canon Nikon Flash Speedlite and Flash Trigger :
flash - Simple Explanation of the Hot Shoe Pins on Canon Cameras and Flashes? - Photography Stack Exchange
Hot Shoe cable - Hardware integration - Emlid Community Forum
Amazon.com : Pixel e-TTL Flash Hot Shoe Adapter with Extra PC Sync Port for Canon DSLRs and Flashguns : Flash Shoe Mounts : Electronics
Canon Removes the Universal Hot Shoe Pin on Its Latest Release | Fstoppers
camera - DSLR Hotshoe wiring to Arduino - Electrical Engineering Stack Exchange
Aquatica Manual Bulkhead Connector with Canon Hot Shoe 18928 B&H
The "E-TTL" protocol, as spoken by Powershot G3 and EOS 50, and a speedlite 550EX
Pin layout on Canon flash hot shoe -- Flash and Studio Lighting in photography-on-the.net forums