Camera Shutter Tester Arduino ESP32

Camera Shutter Tester Cheap-Easy-it-Works

Arduino ESP32 based shutter tester using three lasers. Based on the Arduino platform, but using a much faster processor, the ESP32.

The use of three lasers & three receivers allows for correct travel time measurement for each shutter curtain of a focal plane shutter, which is most important to ensure even exposure across the frame and detect shutter blanking & bouncing. Flash sync can also be confirmed.

DIY builds that use a single sensor or Audacity simply will not work. Both shutter curtains must be set to travel at the same speed, which is simply not measurable using just one sensor. Similarly there will always be an inherent error when measuring a single light point with a sensor, which of course will be wider than a single photon. This error can be mathematically calculated and corrected using a simple algorithm, if multiple sensors are used.

A shutter speed of 1/500s can have a shutter slot width of just 2mm. So a sensor of 1mm width, would measure 3mm, giving a 50% error!! This is why single sensors or designs built without an understanding of how a focal plane shutter actually works, will always have a very high reading error. This design, of course, calculates these errors, giving a true and accurate reading of shutter speed.

Just a note on 'shutter speed'. This is a misnomer. The shutter always moves at the same speed. It is the time of second curtain release that determines exposure. A camera with sync speed of 1/30s will allow the first curtain to fully open (flash fires) and then second curtain starts to close. Moving to 1/60s the second curtain starts to close when the first curtain is only half open. At 1/20s (actual speed. It is just called 1/125 for human brains) the second curtain will start to close when the first curtain has travelled only a quarter. This halving continues all the way to the fastest 'shutter speed' yet the curtains always travel at the same speed.

The shutter tester is designed to use cheap, easy to obtain parts from Ebay (or cheaper still, but longer postal times, Aliexpress). It is up to the builder to decide what enclosures (if any) to use. Finished examples can be viewed on the Photrio thread.

A comprehensive build guide thread & user group can be found on on Photrio.

https://www.photrio.com/forum/threads/build-a-shutter-tester-for-focal-plane-shutters-cheap-easy-it-works.197756/

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

Please refer to Photrio for further build help & to let us know you are building the tester..

Supplies

Parts to build the project come as ready built modules. This negates the need for little, if any, soldering.

The modules are connected together with pre-made Dupont wires, so again no soldering required.

This allows us to use a very fast microprocessor, which comes pre-mounted onto a board, complete with power supply and USB interface.

There are various options the builder can choose along the way. The simplest build is without LCD, TFT display, or light-meter, with the the measurements displayed directly onto the computer screen.

The best (imo) version is with the TFT colour display. It gives all of the information required, including averages and makes it a stand-alone project.

Using a TFT display, the LCD is not required & this is still only included for legacy builds. The LCD only shows a fraction of what is shown on the TFT.

The case, buttons etc are again up to the builder.

Step 1: Shutter Tester Parts

The PDF file gives a list of all the parts required & links to AliExpress suppliers. Link, of course, could change & also check the supplier sends to your country.

Step 2: Hardware Build

The hardware build document gives some basic guidance and layout for the sensors. Arranging the sensors diagonally, as shown in the pdf document allows both vertical and horizontal shutters to be tested. The drawback of this, is that the camera has to be very carefully aligned. If only testing horizontal shutters, mounting the three sensors horizontally makes camera alignment far easier.

Photos are shown, mainly of earlier Arduino builds, but these still show how the sensors can eaily be mounted on wooden blocks or even Lego.

Step 3: Wiring Guide

The wiring guide document, together with the schematic diagram shows where all of the connections are made.

Using the Dupont wires, no soldering is required (other than for the optional light-meter)

Step 4: Installing Drivers

For the ESP32 processor board to connect to your computer, a suitable USB driver must be loaded.

If purchasing the recommended ESP32 board, the CP2012 driver used, is not normally pre-installed on a computer. The PDF guide shows how to load this driver to your computer.

Step 5: Arduino IDE Software Load

To view the Shutter Tester output on a computer screen, as suitable serial monitor program must be used. The PDF document details how to load Arduinio IDE which has a serial monitor function.

Note:- If you are not planning to view the shutter Tester output on a computer, this step can be jumped.

Step 6: ESP32 Firmware Load

The computer code that runs on the ESP32 microcontroller is called Firmware.

This firmware must be loaded onto the ESP32 board, using a USB cable and suitable computer software to transfer the firmware from the computer to the ESP32 board.

The software is called Flash Download Tool, from Espressif Systems. The manufacturers of the ESP32 microcontroller.

Details of where to download & how to install the software are found in the PDF document.

Instructables do not allow the hosting of this software, the drivers or indeed the firmware for this project.

The PDF guides have links to my GitHub, where these can be found.

billbill100 (github.com)

Step 7: Operating Guide

The operating guide is the PDF below.

Step 8: Build a Project Box

This guide details one method for cutting a hole in a project box for the TFT screen and a template for this & the buttons, if using the suggested project box.

Note that the encoder requires a 6mm hole and the buttons a 13mm holes.

If wishing to bolt the TFT screen to the box, 3mm holes are required.

The template shows the encoder. It is not currently used for this project, due to legacy issues from LCD only builds. It is still worth buying the encoder & either fitting it, or leaving space for future fitment, as it maybe used in future updates.

Five buttons are shown, but only four are required. Again a fifth button was added to allow for future updates.

Step 9: Film-Gate Sensor

The Lasers work perfectly when aligned horizontally, using the ‘block of wood’ layout, however trying to align them in a diagonal formation with the sensors, for testing both horizontal and vertical sensors is quite challenging.

A different approach is to mount the sensors in a small box that fits into the film-gate of the camera and then a LED light is used to provide the light, shining into the mirror-box. There is no room in the sensor box for the complete module, so the capacitor & resister have to be soldered directly to the legs of the sensor.

The Lasers & sensors are arranged so the left and right Laser are spaced 32mm horizontally and 20mm vertically, with a central sensor as per the diagram below. With this layout, they can be used for both horizontal and vertical shutters. Placing them all horizontally or vertically is an option, which makes camera alignment easier, but it will then only work for that orientation of shutter. Separate sensor boxes could be made for horizontal & vertical shutters.

Another sensor box can be made for the light sensor.

Full details in the PDF below.