Figure 1 Simple Circuit for Microcontroller Control of Gopro by Grounding Power/Mode Pin

Gopro exposure research and progression

This idea works for older gopro and older firmware. New firmware check the EEPROM before allowing the add on accessory to interface with the camera.

Figure 1 simple circuit for microcontroller control of gopro by grounding power/mode pin

In order for an attachment to interface with the gopro it needs to identify itself this is done using the I2C bus and EEPROM. The first memory location is a 9.

Figure 2 Schematic for one button mode control with I2C interface[1]

Figure 3build circuit [2]

Figure 4 alternate shematic for the same implementation [3]

The EEPRO selected does not matter so long as it is 400kHz speed and single byte addressable I2C. To work with the breakout board already selected the package should be sot-235 or similar surface mount with 5-6 pins. The memory locations are simple to program with an arduino (

Figure 5 Alternate schematic for exposure[4]

Figure 4 gives the schematic for a software interface with the shutter rather then a hardware interface for one button mode power/mode button. This is more powerful and potentially harder to achieve. Example code was provided with the schematic on the forum.

// Get the current state of ID1

int start = digitalRead(GOPRO_ID1);

// Low pulse on ID2 to tell the camera to get ready

digitalWrite(GOPRO_ID2, LOW);

delayMicroseconds(340);

digitalWrite(GOPRO_ID2, HIGH);

// Wait for ID 1 to change state

// to indicate the camera is ready

while(digitalRead(GOPRO_ID1) != start) {}

delay(62);

// Low pulse on TRIG to tell the camera to take a

//photo

digitalWrite(GOPRO_TRIG, LOW);

delayMicroseconds(340);

digitalWrite(GOPRO_TRIG, HIGH);

Serial.println("Photo taken");

// 1.5 second delay between photos. Longer or shorter works fine.

delay(1500);[5]

Parts needed for implementation

• Breakout board
• 24AA0 SOT-23-5 package EEProm
• Current limiting resistor
• PNP transistor switch
• 2 digital pins
• 2 PWM Pins
• 3.3v Microcontroller or Buck Converter

If ever it is necessary or desirable to have video streaming and the project has reached a point of stability where it would be feasible to attempt to get full remote camera functionality working the following schematic is an excellent starting point.

Figure 6 Full Gopro interface schematic[6]

Additional resources can be found at the following links.

How to hack a GoPro Hero3 for wired remote control - YouTube

GoPro User Forum • View topic - How to Hack your GoPro Hero 3 for FPV (Aerial Video)

GoPro User Forum • View topic - GoPro Hero2 - Composite Video Out thru BUS connector DONE!GoPro Hero HD bus interface | Ridax electronics blogGoPro Hero 3 Black Super One Button ModeGoPro HD Hero Camera ControllerGoPro HD Hero 2 Arduino Control | mikenz.geek.nz

GoPro HD Hero Camera Controller

GoPro User Forum • View topic - How to make a one button remote for a GoPro

GoPro Camera Power Connector

GoPro Hero3 Teardown - iFixit

Fixinghero3 « GO PRO HERO 3 WONT TURN ON SOLUTION HERE DEAD CAMERAS

[1]

[2] ibid

[3]

[4]

[5] ibid

[6]