Lightning Capture for Camera

Build a cheap device for your camera, to automatically photograph lightning as it happens.

Based on Arduino (but using a faster ESP32 processor), this clever device allows your camera to wait in standby, watching for lightning and take a photo the instant lightning is seen.

A dslr or mirrorless camera with a cable release socket will be required.

Using a battery powered processor, complete with built in-charger and off-the-shelf modules, the device can be quickly and easily built. There is no need to make or order complicated circuit boards (pcb).

A little soldering skill is required, as is a bit of computer skill to load the firmware onto the device, but there are how-to guides for each step and a user forum on Photrio.

There are two versions that can be built. The full version includes an Oled display, with parameters that can be changed. A basic model, with minimam components, that just works, using the default parameters.

Now the caveat. The device has been built & tested and it works great indoors. However there has yet to be thunderstorm to test it in the real world. As soon as a suitable storm blows through, I will be running outside to fully test the device.

This is a new project, so documentation may change over the coming weeks.

Whilst I will try to keep Instructables current, the latest documents and firmware will always be found in my github repository.

billbill100 (github.com)

For help & support, there is an active Photrio thead

Lightning Capture Device - Cheap - Simple & it works (photrio.com)

Parts are easily obtainable from AliExpress. Delivery speed has dramatically increased in recent years, many of the shops there offer 7 day delivery time.

Note batteries come by sea and land, so you may want to order these items from a local supplier.

A list of required parts, with links, is in the attached document. They are all cheaply available and there is no need to make complicated circuit boards or 3d printed parts.

The project can easily be built using pre-made modules and connecting them with Dupont jumper wires. There is a small amount of soldering required.

A plastic project box can easily be cut & drilled to house the modules.

The attached document shows all of the wiring between the different modules. Use this in conjunction with the schematic. Using the same colour Dupont wires as in the document and schematic will make things easier to follow.

The microprocessor board features a USB connector and on-board USB interface. A driver is required on the computer to enable the firmware to be loaded. The board for this project features a CH340 driver, which may already be installed on your computer. If not, a guide how to check and install the driver is included.

Instructables does not allow hosting of the firmware of firmware transfer (flashing) software. For this & all of these documents, go to the github repository.

The firmware is transferred from the computer to the ESP32 board via a USB cable.Full details are in the document.

The camera is connected to the Lightning-Capture via a cable and fully isolated opto-isolator board. No electrical signals travel from the device to the camera. This ensures no damage can occur to the camera.

The Lightning-capture has been tested with Nikon & it works fine. People with other brands may have to experiment a little. Some cameras use two wires and resisters to degerming half & full press. Whether the pre-made cables have these resisters built in or not, I do not know. A little experimentation maybe required.

The schematics show all of the wiring connections.

There is one for the full and one for the minimal design.

The latest version of the guide will always be available on Github. Below is just a print of the version available when creating the Instructables page, although I do try to keep Instructables up to date as well.

I would really be grateful if you start to build the Lightning Capture Device, that you go to the Photrio thread and say hi. Also please post photos of your completed project.

Please refer to the Photrio thread for further build help

Lightning Capture Device - Cheap - Simple & it works (photrio.com)

GitHub repository where all documentation & code can be found. billbill100 (github.com)

V1.1   30/07/2024

Lightning Capture Operating Instructions

Buttons

Blue button.      Each time this button is pressed, the red marker will move to the next parameter.

Blue knob.         Turning the knob will change the parameter.

Green.                 Starts the Lightning Capture.

Blue button.      Ends Lightning Capture & returns to parameter screen.

LEDs

Red LED.                            Power.

Yellow LED.                       Half Press Shutter – watching for Lightning.

Green LED.                        Full Press Shutter – taking a photo.

Light Sensor

Blue/White screw.          Adjusts sensitivity of Light Sensor.

Green LED.                        Light Seen

On-Screen Parameters

Pre.

Sets how long the camera will wait with shutter ‘half-press’ watching for lightning.

Pst (post)

How long the shutter will stay open for, when triggered by lightning.

Battery

Alternates between voltage and percentage. Only show whilst in parameter menu

Note:-

The two parameters above are normally set to INF (infinite) and Cam (camera settings). However, they can be changed from 1/1000s to 480 seconds. See ‘Fun & Games’ below.

Basic operation – Full version

The Light Sensor must be adjusted using a small screwdriver, so that in ambient light, the green led on the board just turns off. Note, there is a secondary green power light on the board, which is always on.

The Lightning Capture is connected to the camera using a suitable shutter release cable.

The camera must be in manual mode, including focus & iso.

Focus the camera either at infinity or at a suitable distance, if including foreground. Then ensure auto-focus is turned off.

Set the camera iso, shutter speed and aperture as appropriate. This will involve a little trial and error and setting will depend on ambient light and if you are being creative with light-painting or fill flash for the foreground.

Press the Green start button & the camera will act the same way as half-pressing the shutter button and the Yellow LED will illuminate (ensure LEDs will not fog the photo)

When lightning is seen, the shutter will be fully pressed and the Green LED illuminate.

The camera will now take a photo, for the duration the camera shutter speed has been set to.

Note:- The Lightning Capture box has no idea of the camera settings, so after seeing lightning, it will immediately release the shutter and half-press again, watching for the next lightning strike, but the camera settings take priority.

To stop lightning-capture, press the blue knob. The unit will close the shutter and return to the initial menu screen.

Basic operation – Minimal version

The Light Sensor must be adjusted using a small screwdriver, so that in ambient light, the green led on the board just turns off. Note, there is a secondary green power light on the board, which is always on.

The Lightning Capture is connected to the camera using a suitable shutter release cable.

The camera must be in manual mode, including focus & iso.

Focus the camera either at infinity or at a suitable distance, if including foreground. Then ensure auto-focus is turned off.

Set the camera iso, shutter speed and aperture as appropriate. This will involve a little trial and error and setting will depend on ambient light and if you are being creative with light-painting or fill flash for the foreground.

When powering on, the unit goes straight into Lightning-capture mode and the Yellow LED will illuminate (ensure LEDs will not fog the photo) (There is no Green button to start)

When lightning is seen, the shutter will be fully pressed and the Green LED illuminate.

The camera will now take a photo, for the duration the camera shutter speed has been set to.

Note:- The Lightning Capture box has no idea of the camera settings, so after seeing lightning, it will immediately release the shutter and half-press again, watching for the next lightning strike, but the camera settings take priority.

To stop lightning-capture, turn the unit off.

Fun & Games with the Full version.

The ‘pre’ parameter specifies how long the Lightning Capture will wait for lightning. The default is infinity, however this can be set between infinity, 480 seconds to 1/1000s. At the end of this time, a photo will be taken, even if lightning is not seen. This can be used as an intervalometer, or if the camera has pre-capture & is set to do so, one can save the pre-capture photographs.

The ’Pst’ or Post parameter sets how long the shutter stays open for. Normally this is set on the camera, however if the camera is set to Bulb mode, then the Lightning Capture can control the exposure time.

The camera of course, need not be set to Manual or Bulb mode. For example, it could be set to continuous shooting at 1/60s. By setting the Pst to 5s, one would get a burst of 1/60s stills for 5 seconds.

This could be used to take a series of shorter photographs once lightning is seen, for manual blending & editing.

For cameras with pre-capture, this can be used to capture the pre and post lightning (removing latency issue) by setting the camera up for pre-capture. When lightning is seen, the pre-captured images will be saved and a series of post-images will be taken depending on the ‘Pst’ setting.

Note:- The Lightning Capture has a minimum shutter press length of 1/1000s. It is unlikely a faster shutter speed would be required, however if the camera is set to something like 1/8000s, there may be multiple 1/8000s images taken, as the camera will ‘see’ the shutter is pressed for 1/1000s.

General Notes

Shutter latency is the time from when the shutter is pressed to the time the camera has lifted the mirror & opened the shutter. This can be many milliseconds. The Lightning capture also has latency between lightning being seen and it operating the camera. This cannot be helped. All electronics will have some latency.

For this reason, the Lightning Capture has been coded to minimise latency, with priority given to looking for lightning and operating the shutter, before updating the display. This is also why the camera sits in ‘half-press’ mode waiting for lightning.

Caveat.

The Lightning Capture has been built & tested and all works well. The one thing that has not been tested is photographing actual lightning! It is just a waiting game until a suitable storm comes along.