Build a shutter tester for Focal Plane shutters - Cheap, Easy & it Works

[Flighter]

I might put this project to one side & work on a light meter. There are some good boards around with built in oled screen & lipo battery charger. Might also be fun to build new electronics for a defunct camera. I will keep an eye out on ebay.

Both sound very interesting, please keep us updated.

 

[Niglyn]

Hi Guys,

Thought the Easter break may have allowed time for shutter timer creations to be built & posted here?

For the Mk2 shutter tester, I would like another two lasers mounted a 36mm, this would give full flash sync confirmation. The sensors & lasers would be mounted in two project boxes, requiring holes drilled at 32 & 36mm centres.
Alas I currently have no workshop (not even a soldering iron or hot-glue gun) so unless there is anybody local with a milling machine or accurate pillar drill, this will have to wait. The project would also be ported onto a faster microcontroller.


In other news, the light meter code is coming along nicely. A basic version is running on a Nano.
However it needs to be portable & battery powered, the simplest method would seem to be using a Lilygo T3-Display module. It is a development board (like the Nano) having a much faster processor, more memory, built in lcd screen and lipo battery connection & charger. The downside is of course, the price, over£20.

Just arrived are my lilygo boards & also a small oled display (which I think is too small for any practical purpose).

 

[snusmumriken]

I've been distracted from this project for a bit. Just got back to it, and found my laser sensors had gotten out of line. As I am about to reduce the beam width to 1mm, I felt in need of a utility to help line them up.

The simple Arduino sketch attached can be loaded up to your Arduino Nano (or whichever board you have) in place of Nigel's shutter tester sketch. Keep the wiring connections the same. The only extra item you need is a piezo buzzer (like these, eg). Connect one wire to pin 9 and the other to GND.

Nothing will happen until one or both of the sensors is lit by its laser beam, at which point the LED marked L on the Arduino board will light up, and the buzzer will sound. For simplicity, I've assumed you will cover one of the lasers with a piece of card or something while you align the other.

Hope this is helpful. Once your sensors are lined up, upload Nigel's sketch in place of this one and run the shutter test.

 

[snusmumriken]

My LCD display didn't arrive. I asked the company to send another and that hasn't arrived either. So I've decided to live without it and rely on the serial output. I reckon I will only ever use this device tethered to a computer anyway.

I have also adapted (see attached) Nigel's code to display the deviation of actual exposure from target, in stops and third-stops. To do this, one has to interact with the code and state what the target shutter speed is. That dialogue happens in the Serial Monitor after the shutter is fired. The nominal speeds stated on the camera are of course only approximations because they are not whole stops apart (e.g. 125 is not 2x60). So I have used a series of target speeds that half at each step from 1 sec. They are listed at the start of the sketch (nomSpeed[ ]). You just state what the camera dial says.

I think it is all working correctly, but would appreciate if someone with know-how would check the code that calculates stops and thirds.

I haven't yet incorporated the nice tables and averaging of Nigel's later versions. In part that is because my shutter performance seems to be very consistent.

My conclusions about the state of the shutter in my M6 have changed a little for the better: all speeds now seem spot-on except 1/500 (1/3 stop slow) and 1/1000 (1 stop slow at the first curtain). The camera probably needs a CLA, but I'm not going to make that decision until I have narrowed the width of my laser beams down to 1mm and checked again.

 

[Niglyn]

My LCD display didn't arrive. I asked the company to send another and that hasn't arrived either. So I've decided to live without it and rely on the serial output. I reckon I will only ever use this device tethered to a computer anyway.

I have also adapted (see attached) Nigel's code to display the deviation of actual exposure from target, in stops and third-stops. To do this, one has to interact with the code and state what the target shutter speed is. That dialogue happens in the Serial Monitor after the shutter is fired. The nominal speeds stated on the camera are of course only approximations because they are not whole stops apart (e.g. 125 is not 2x60). So I have used a series of target speeds that half at each step from 1 sec. They are listed at the start of the sketch (nomSpeed[ ]). You just state what the camera dial says.

I think it is all working correctly, but would appreciate if someone with know-how would check the code that calculates stops and thirds.

I haven't yet incorporated the nice tables and averaging of Nigel's later versions. In part that is because my shutter performance seems to be very consistent.

My conclusions about the state of the shutter in my M6 have changed a little for the better: all speeds now seem spot-on except 1/500 (1/3 stop slow) and 1/1000 (1 stop slow at the first curtain). The camera probably needs a CLA, but I'm not going to make that decision until I have narrowed the width of my laser beams down to 1mm and checked again.

Hi sn,
Code looks good. Unlikely that it will fit into version 3, as there is no more space for global variables or screen printing. Would be clever if the code guessed the nominal shutter speed, rather than having user input.

Don't know if manufacturers use nominal shutter speeds, eg, 1/60s or just display 1/60 and actually use 1/62.
One would have to refer to the service manual. I only play with old cameras, so close-enough is good-enough.

I'm now working on a simple exposure meter (that works). Originally it was an all singing-dancing touch-screen Sekonic killer, which I mostly got working, but now decided it should be a replacement and check meter for old cameras reflective exposure meters. Prototype is sitting here working, but waiting for Aliexpess to send me the lite version of esp32, which has low current components and in-built lipo charger & a few other bits.

 

[snusmumriken]

Don't know if manufacturers use nominal shutter speeds, eg, 1/60s or just display 1/60 and actually use 1/62.
One would have to refer to the service manual. I only play with old cameras, so close-enough is good-enough.

Thanks for checking the code.

Irrespective of the mfrs’ ideas about this, my POV is that I want a 1-stop change in shutter speed to match a 1-stop change in aperture. The difference is small relative to the accuracy achievable with mechanical focal plane shutters, but it nonetheless seems a better target.

Could (try to) make the target automatically recognisable, but that would be problematic if the shutter was 1 stop or more off-target, which is not unlikely with the extreme high and low speeds.

 

[Niglyn]

Could (try to) make the target automatically recognisable, but that would be problematic if the shutter was 1 stop or more off-target, which is not unlikely with the extreme high and low speeds

If the camera is more than a stop out, then there are bigger problems )

I have added a speed guesser to the code. It works great, obviously the camera has to be within a reasonable tolerance for it to work.

Arduino Nano memory is now so full, it cannot accept anymore global variables and was starting to give random characters onto the screen, a sure indication that it is full, even with the LCD code removed.

It is time to port the code to the esp32. Will update the code & schematic & continue the build blog for peeps to follow if they wish.

 

[Niglyn]

#7 Moving on from the Arduino Nano onto the ESP32 platform.
The Nano, whist working fine, is now so full that nothing else can be added.
The ESP32 is also much faster & the screen output can be raised from 115200 to much faster rates, allowing for an almost instant display.

Ideas for future improvement include shutter speed guessing, where the software will display what it thinks your camera speed dial is set to. (Camera needs to be reasonably accurate for this to work) and how far out your camera is. (This is actually almost finished)

Adding a setup routine, to check laser alignment & test if newer sensors are being used, which have the output reversed.

Adding a further two lasers at the edge of the gate & an input from the flash PC sync socket.. This will allow for full flash sync checking. This will be long term due to my lack of workshop t the moment.

There are numerous ESP32 development boards. Any should work. I am using the nodeMCU-32S which is the 38pin board. This goes well with the 38pin screw terminal breakout board. Cheap as chips from Aliexpress, but delivery can be weeks to months, depending on your order value. My last order (express air-mail due to price & type of goods) took four days from China to Royal Mail, who then took five days to deliver. Next post will have links to the development & breakout board.

 

[Niglyn]

#8
Below are links for all the parts required on the AITEXM ROBOT store on Aliexpress.
Buying from one store can get express shipping. Last time I ordered from this store & also the Lilygo store, got combined express shipping & parts arrived four days after order. Royal mail took a further five days to deliver )

It is of course far quicker to order from a UK based Ebay or Amazon shop, but prices will be higher.

KY-008 laser

https://www.aliexpress.com/item/4001019189714.html?spm=a2g0o.store_pc_allProduct.8148356.11.28202af7wf92BB&pdp_npi=2%40dis%21GBP%21%EF%BF%A10.41%21%EF%BF%A10.33%21%21%21%21%21%4021038eda16822659186328563e121d%2110000013526117842%21sh

Laser rx

https://www.aliexpress.com/item/4001062955471.html?spm=a2g0o.store_pc_allProduct.8148356.20.28202af7z62pJJ&pdp_npi=2%40dis%21GBP%21%EF%BF%A10.70%21%EF%BF%A10.57%21%21%21%21%21%4021038eda16822659186328563e121d%2110000013988484369%21sh

LCD - Ensure to select LCD2004+I2C

https://www.aliexpress.com/item/1621301904.html?spm=a2g0o.store_pc_allProduct.8148356.5.4b12199dYJOFoN&pdp_npi=2%40dis%21GBP%21%EF%BF%A10.67%21%EF%BF%A10.55%21%21%21%21%21%40211b88ef16822665363886443ed9a3%2112000016191401546%21sh

Push-button. Mounted on board, so no soldering required. 2 needed. Cheaper options if you can solder.

https://www.aliexpress.com/item/32809543999.html?spm=a2g0o.store_pc_allProduct.8148356.61.3a43635awyfKSu&pdp_npi=2%40dis%21GBP%21%EF%BF%A10.36%21%EF%BF%A10.29%21%21%21%21%21%40211b88ef16822667666575180ed9a3%2164431470782%21sh

Dupont wires - get the 30cm male to female ones.

https://www.aliexpress.com/item/32835984781.html?spm=a2g0o.store_pc_allProduct.8148356.5.1dcb4daaA6wdWX&pdp_npi=2%40dis%21GBP%21%EF%BF%A10.60%21%EF%BF%A10.48%21%21%21%21%21%40211b88ef16822669756512066ed9a3%2112000016220209500%21sh

ESP32 development board & breakout board - Ensure to select last item Type C ESP32 board & breakout board.

https://www.aliexpress.com/item/1005004438768602.html?spm=a2g0o.store_pc_allProduct.8148356.1.334a38aflyHJQd&pdp_npi=2%40dis%21GBP%21%EF%BF%A12.33%21%EF%BF%A11.89%21%21%21%21%21%4021038eda16822658671308044e121d%2112000029183035466%21sh

 

[eli griggs]

Hello Everybody, #1

There are many home-brew shutter testers out there, some use audio to try to detect the speed, others use an Arduino and one sensor (so will not work correctly) and there are better ones that use two sensors.

A problem seems to be a misunderstanding of how a focal plane shutter works & how it has two curtains. Shutter speed is a misnomer. The shutter curtains always travel at the same speed. It is the time difference between first & second curtain release, that varies the exposure. There are plenty of explanations of this & nice youtube slo-mo videos, which explain the workings better than I can in plain text.

So here is another one, mine. It is based on an Arduino Nano and Arduino laser tx rx modules & anybody who is able to tinker with camera repairs, should be able to make one without (much) difficulty. Parts are easily available on Ebay, Banggood, Aliexpress etc. & I will supply the code upon request.

Camera repair manuals often specify curtain speed. Without a way to measure the speed of each curtain, one cannot follow the calibration procedure. Both curtains have to travel at the same speed, else uneven exposure across the frame will occur. This unit measure the speed of each curtain and also the actual exposure (1/250 for example) at either end of exposure, so it can easily be seen if there are exposure problems

There are a number of stages to getting familiar with Arduino and setting up. I will go though these sections, to enable peeps to follow along & build one. Those familiar with Arduino can go right ahead, build the unit & load the code.
The steps are as follows:-
Buying the bits
Understanding how to use one's computer to talk to & load code onto the Arduino
Setting up the LCD, wiring & loading 'library' files
connecting the lasers modules to the Arduino
Loading the shutter tester code & setting up the device.

I built one on a piece of scrap wood stick, using a diode, a photocell, and an AA battery, connected to a PC with Audacity sound/recording software, with a mini audio plug, plugged into the microphone on the computer and using a Surefire flash light, pointed into the front of the camera lens opening.

The sensor was on the back side of the camera and, when the shutter was triggered, the sensor read the first microsecond of the opening of the shutter, to the end of the light exposure, giving an actual time duration of the opening and closing operation.

Seeing the entire period of the shutter opening and closing is, IMO, very accurate and nothing more is needed.

Simply, fast to make and if you saw that first primitive effort, you'd just shake your head in disbelief.

Cheers!

 

[Xylo]

nothing more is needed.

Where's the fun in that?

 

[eli griggs]

More time to go out and shoot knowing your shutter's intentions.

 

[Niglyn]

Seeing the entire period of the shutter opening and closing is, IMO, very accurate and nothing more is needed.

Simply, fast to make and if you saw that first primitive effort, you'd just shake your head in disbelief.

I have made many heath-robinson contraptions in my time, that is half the fun, cobbling together something that works

A single photo-diode or similar will not show curtain bounce, flash sync, uneven exposure across the frame., curtain speed imbalance or curtain blanking. You also have the issue of non coliminated light, leading to inaccuracy.

Using two photo-diodes and the left/right audio input would be an upgrade

 

[Xylo]

Using two photo-diodes and the left/right audio input would be an upgrade

And using either a laser gate or a collimated light source would also help a lot...
And not having to use an excel spreadsheet to manually do all the data logging would be a big helper. If only there was software to do that

 

[eli griggs]

Ill h

I have made many heath-robinson contraptions in my time, that is half the fun, cobbling together something that works

A single photo-diode or similar will not show curtain bounce, flash sync, uneven exposure across the frame., curtain speed imbalance or curtain blanking. You also have the issue of non coliminated light, leading to inaccuracy.

Using two photo-diodes and the left/right audio input would be an upgrade

I'll have to consider this upgrade, as I did no use the second photocell in the RadioShack package.

 

[Niglyn]

I'll have to consider this upgrade, as I did no use the second photocell in the RadioShack package.

Do RadioShack still exist? They died many many years ago in the UK. They were called Tandy. They offered a small range of electronic components at exorbitant prices, but they were one of the few places available to that sold components. Maplin went the same way, they seemed to set their range of components from the 1970s and never updated them.

Problem with photo-diodes is that they are too large, so much accuracy is lost.

 

[Niglyn]

#9
Well the code for the ESP32 version of the shutter tester is finished & working fine.
It now incorporates a guessing hat, so providing your camera is reasonably accurate, it will know the speed that has been dialled into the camera.
This feeds into Snu's code to show the deviation from camera set speed.

Have also added a setup & alignment utility, again based on Snu's idea. It allows the user to align the lasers & receivers and also shows if the rx modules are the later type, having an inverted output. If so, this can now be set within the alignment routine.

Using the nodeMCU-32S board with 2102 UART also allows a baud rate of 500000. So output to the screen is almost instantaneous.

Tbh, for those wishing to make the tester and have not yet bought any parts, would suggest going straight for the nodeMCU-32S board. The setup is exactly as detailed for the Arduino Nano in previous posts, with the additional step of adding the ESP32 board details to Arduino IDE software. Plenty of youtube videos detailing how to do it.

The LCD is optional, if you want to save £3 as all the LCD output and far more gets sent to the computer screen. It will also work without without the two push-buttons (if you are really tight) although they are required for the setup & alignment utility.

For a copy of the code, just post a picture of your completed ESP32 based shutter tester

 

[eli griggs]

Do RadioShack still exist? They died many many years ago in the UK. They were called Tandy. They offered a small range of electronic components at exorbitant prices, but they were one of the few places available to that sold components. Maplin went the same way, they seemed to set their range of components from the 1970s and never updated them.

Problem with photo-diodes is that they are too large, so much accuracy is lost.

I Googled that first question and, yes, online, and in some 400 independent stores, according to this link.

There are still in my general area, 24 miles up the road and the next two, about 55miles from here but the rides are nice and having a camera kit with you for the trip plus linger.

I'll take a look at the online site, though they have fewer items than yesteryears.

https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.wate.com/news/does-radio-shack-still-exist/%23:~:text%3DSo%2520does%2520Radio%2520Shack%2520still,of%2520REV%252C%2520Associated%2520Press%2520reports.&ved=2ahUKEwjsnpOci8b-AhWWmWoFHcNHBp4QFnoFCIoBEAU&usg=AOvVaw2-3EkU5mGmW5-vEebr1inP

 

[alinCiortea]

Is either one of these boards ok?

Placa dezvoltare Lua Wifi NodeMCU, CH340G, ESP8266

Placa de dezvoltare NodeMcu IoT Wireless cu Wifi ESP8266 compatibila Arduino IDE, ideal pentru Internet of Things.

www.sigmanortec.ro

Placa dezvoltare ESP32, ESP-WROOM-32, WiFi si

Placa de dezvoltare compatibila Arduino IDE si program Lua, ESP32 cu Bluetooth si Wifi integrat.

www.sigmanortec.ro

I'm trying to buy locally (hate waiting for things from aliexpress) and I have absolutely no idea what I'm doing
I've built a shutter tester before (single LED, arduino) but in a 'monkey sees, monkey does' fashion so I'd rather ask a stupid question than see the magic smoke escape my components.

Thank you!

 

[Xylo]

Do RadioShack still exist? They died many many years ago in the UK.

I know that they all were converted to The Source decades ago here in Canada. Circuit City had bought all the stores, then they went bankrupt and the chain was bought by Bell Canada.

But for parts in the UK you can check Farnell (https://uk.farnell.com/)
they are part of the Element14 group.
There's also Mouser Electronics in Britain (https://www.mouser.co.uk/).

While their prices are never as good as AliExpress, they are top notch when it comes to the quality of their components.

 

[koraks]

Is either one of these boards ok?

Placa dezvoltare Lua Wifi NodeMCU, CH340G, ESP8266

Placa de dezvoltare NodeMcu IoT Wireless cu Wifi ESP8266 compatibila Arduino IDE, ideal pentru Internet of Things.

www.sigmanortec.ro

Placa dezvoltare ESP32, ESP-WROOM-32, WiFi si

Placa de dezvoltare compatibila Arduino IDE si program Lua, ESP32 cu Bluetooth si Wifi integrat.

www.sigmanortec.ro

I'm trying to buy locally (hate waiting for things from aliexpress) and I have absolutely no idea what I'm doing
I've built a shutter tester before (single LED, arduino) but in a 'monkey sees, monkey does' fashion so I'd rather ask a stupid question than see the magic smoke escape my components.

Thank you!

The ESP8266 has relatively few GPIO pins for truly generic use. I haven't done a pin count on this project, but I think it's going to be a borderline case. So I'd drop the first board in favor of the second.

Keep in mind that all ESP boards are 3.3V logic, so their GPIO pins are also only rated for that voltage.

 

[snusmumriken]

Keep in mind that all ESP boards are 3.3V logic, so their GPIO pins are also only rated for that voltage.

Isn’t that going to complicate things? The lasers require 5V. Can the board‘s voltage regulator cope with a 5V input?

 

[koraks]

Isn’t that going to complicate things?

Yeah, but virtually all commonly used microcontroller systems are 3.3V (or even lower) these days. The ATMega328P (the microcontroller on the Arduino Nano, UNO etc.) is a relatively old piece of technology.

Can the board‘s voltage regulator cope with a 5V input?

The voltage regulator only powers the microcontroller and its peripherals. It does not protect the GPIO's on the controller or provide some kind of voltage translation functionality there.

A 3.3V safe GPIO input from a 5V output (e.g. a laser detector) can be made with a simple voltage divider; e.g. a 3k3 resistor from GPIO to GND and 1k8 from the 5V digital signal to the GPIO. Note that this is only unidirectional; it shifts a 5V signal coming from a peripheral down to around 3.3V going into the controller.

Sometimes you can even get away with a simple resistor between a 5V signal and a 3.3V microcontroller input; the resistor will limit current to a safe level for the GPIO and an internal diode in the microcontroller limits the voltage at that node to the microcontroller's supply voltage. Something like 1k will usually work. There are many ways to skin a cat.

I haven't looked into the laser modules used here, but there's a good chance they also work on 3.3V and don't strictly require 5V. It depends on the implementation. Many simple peripherals allow to be operated in a fairly broad voltage range.

 

[ic-racer]

I was just looking at laser modules today and indeed there are 3v ones.

 

[snusmumriken]

I was just looking at laser modules today and indeed there are 3v ones.

Where were you looking, as a matter of interest? I’d really like 3.3v lasers with a narrower beam.