Speedlight trigger - NEW

Device is a photo flash trigger that responds to sound, beam interruption, it works as a timer and controller for (drop) valves control.

Dec 14, 2021

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Components and supplies

1

2.8 INCH TOUCH SCREEN FOR UNO/MEGA DEVELOPMENT BOARD WPSH412

1

Arduino UNO

Tools and machines

1

Soldering iron (generic)

Apps and platforms

1

Autodesk tinkercad.com

1

EasyEDA designer

1

Arduino IDE

Project description

Code

Timer_active.ino

arduino

Main menu code

arduino

Drop_timer.ino

arduino

Trigger_active.ino

arduino

Trigger.ino

arduino

Timer_active.ino

arduino

Trigger_active.ino

arduino

Num_enter.ino

arduino

Drop_timer.ino

arduino

Num_enter.ino

arduino

Main menu code

arduino

Trigger.ino

arduino

Downloadable files

Port 4 DSLR activation and Arduino port D13 delay

Since I was left with very few free ports due to the touch screen, I had to use port D13 to activate output 4 (DSLR camera activation). The problem with the D13 port is that when we turn on the Arduino, it sends three pulses that trigger the output 4 port (DSLR). I tried to solve it with software but I didn't succeed. Since the IC LM384 is a dual OPA, I used the second OPA as a timer to delay the excitation response from port D13 to output 4. Capacitor C4 and divider R10-R11 determine the inactivity time of the circuit.

Port 4 DSLR activation and Arduino port D13 delay

Image

Part list

Part list

Part list

Part list

Schema

Schema

Image

Positive amplitude amplifier

The output voltage from the preamp varies from 1.5 to 3.5 V approx., and the positive amplitude only from 2.5 to 3.5 V. The Arduino analog input accepts a positive voltage of 0 to 5 V at a resolution of 10 bits (1024 levels), so a resolution of positive amplitude (2.5 to 3.5 V) would be only a fifth of the total resolution (205 levels). The circuit with the PNP transistor (in the real circuit I used BC108b with 240 hfE) amplifies only the negative amplitude and "lowers" inverted amplitude towards zero. In this way, the useful voltage range expands from 0.4 V to 4.6 V (we have 4.2V differences and a resolution of 860-880 levels). The gain and distortion of the output is achieved by changing the resistance R22 (in my case 22K) and selecting a transistor with higher or lower gain (in my case 240 hfE).

Positive amplitude amplifier

Image

Positive amplitude amplifier

The output voltage from the preamp varies from 1.5 to 3.5 V approx., and the positive amplitude only from 2.5 to 3.5 V. The Arduino analog input accepts a positive voltage of 0 to 5 V at a resolution of 10 bits (1024 levels), so a resolution of positive amplitude (2.5 to 3.5 V) would be only a fifth of the total resolution (205 levels). The circuit with the PNP transistor (in the real circuit I used BC108b with 240 hfE) amplifies only the negative amplitude and "lowers" inverted amplitude towards zero. In this way, the useful voltage range expands from 0.4 V to 4.6 V (we have 4.2V differences and a resolution of 860-880 levels). The gain and distortion of the output is achieved by changing the resistance R22 (in my case 22K) and selecting a transistor with higher or lower gain (in my case 240 hfE).

Positive amplitude amplifier

Image

Schema

Schema

Image

Port 4 DSLR activation and Arduino port D13 delay

Since I was left with very few free ports due to the touch screen, I had to use port D13 to activate output 4 (DSLR camera activation). The problem with the D13 port is that when we turn on the Arduino, it sends three pulses that trigger the output 4 port (DSLR). I tried to solve it with software but I didn't succeed. Since the IC LM384 is a dual OPA, I used the second OPA as a timer to delay the excitation response from port D13 to output 4. Capacitor C4 and divider R10-R11 determine the inactivity time of the circuit.

Port 4 DSLR activation and Arduino port D13 delay

Image

Preampifier

Preamplifier are made around OPA LM358 that operate as inverting operational amplifier. The gain of the preamplifier is given by resistor R28, and the best value is from 1M to 1.2 Mohm

Preampifier

Image

Documentation

Lower part of the box (with connections)

Lower part of the box (with connections)

Lid with screen opening

Lid with screen opening

Lower part of the box (with connections)

Lower part of the box (with connections)

Lid with screen opening

Lid with screen opening

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gdusan

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