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High Speed Photography: my third version.

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Hon1nbo

Mon Jun 23 2008, 08:54PM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: Pacific Northwest USA
Posts: 1042

Hello, this is my documentation of V 3.0 of my High Speed Photography setup and photos... The first version was merely a sound sensor using a peizo unit, a disposable camera, and the only control over delay was using the speed of sound. The second generation used a Dual Core Arduino connected to an LCD, a sound sensor (still peizo) a contact sensor, a 25 button keypad, two light sensors and a disposable camera for the flash: this allowed microcontroller controlled timings for delay, and a selection of settings for delay, sensor usage, and event triggering (like a solenoid sending a nail into a balloon)... it worked, but was highly inefficient.
Now comes Generation Three... this one will use a single Arduino, have a microphone or a piezo as the sound sensor, a ultrasonic distance sensor [for moving objects in flight], two laser trip sensors, an adjustable shock sensor, a contact sensor, a hot-shoe for using higher end flashes (fired via an optoisolator and an SCR), an LCD (controlled using the TX pin thanks to a serial LCD piggy-back board) and have a similar keypad for controls, however: this generation must be mobile, as some events I plan to capture (sports and bullets) cannot be done inside the house...
the project will be housed in a box whose size will be determined by experimentation (with events like baseball, where the sensor should be close, I do not want an obstructive or cumbersome enclosure, same with the shock sensor housing)

base assembly:
connect SCR to flash [via hotshoe] and optoisolator and test: done
test reassembly of sensors: [07/03/08] DONE
program arduino: in progress, and mostly complete
LCD piggy-back board: complete, but not tested
build enclosure: CANCELED, bought a pre-made enclosure at a local hobby shop
provide easy to use and flexible connections: decided to use CAT5 cable, as it is flexible, has many connections, is pretty cheap (at least where I buy it), and can come with shielding (since my trigger is sensitive)
assemble event triggering mechanisms: waiting until design finalized for universal trigger...
make circuits fully assembled (after testing): DONE

and for completeness, here is my photo gallery of High Speed: here

[06/26/08]
I got an enclosure that was perfect for the job, the LCD doesn't fit the way it should (I wanted the larger screen) but it still mounts in a satisfactory way...
the unit has all the basic functions working so far, and I made it so that should the SCR, optoisolator, or TIP106 fail I can replace them [or add on to the circuit via a small breadboard while the other components are fixed in cables]
I have decided to make the individual components of the sensors that are not universal made into the cables, such that it will be about the size of a ferrite core around other cables I have seen (max size that is, most will be smaller)

I will have pics when I get a hold of my camera that someone is borrowing...

Ok, after making the unit self powered (the built in battery pack in the case had no connections, so I just used some aluminum foil), I retested all of my sensors, and then tried the new shock sensor and oh crap!: it has a serious delay from the point that it has the shock to the point when it sends out the voltage pulse... I have another thread if anyone can help...
2614231481 F21a35cba9 M

[07/03/08]:
ok, after reading some suggestions here, and doing some testing, it turns out that a piezo through a variable resistor and a sensitive optoisolator works very well! (I tried just a variable resistor and the results were either too sensitive, to impossible to trigger)... I found a good and cheap supplier of CAT5 cable locally (other than tearing apart a good network cable) and plan to use that for making the connections... the actual connection is temporarily made with terminal blocks (which also supply power to certain sensors) but will be replaced with banana jacks as soon as I can get some...
Also, I decided since I am using an Arduino which will have its serial enabled and the Rx not used, I will be testing out an RFID reader I have from Parallax as a safety switch (I don't want a solenoid to shoot a nail until I want it to, don't I?) and as the actual firing switch as well (it did come with TWO tags... a card and a VERY oversize dot...)

Pics of the enclosure are on my flickr pool (see signature) and the various sensors will be up soon, as I used up June's 100Meg limit... I can now update more as soon as I take the pics, but I am saving camera space for the 4th of July...

[07/11/08]
currently waiting for new amp between the mic and the trigger circuit, and am planning to build it.

ArcLight

Mon Jun 23 2008, 10:07PM

Registered Member #341 Joined: Thu Mar 23 2006, 07:41PM
Location: Northern Illinois, USA
Posts: 69

I don't know if it matters, but I flipped the three upside-down images.

1214258432 341 FT48170 2097905709 Cd8aace305

1214258432 341 FT48170 2097905863 47875a2283

1214258432 341 FT48170 2098684000 0dd30fc6e5

Hon1nbo

Tue Jun 24 2008, 03:13AM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: Pacific Northwest USA
Posts: 1042

thank you, the old camera I was using loaded the film from the opposite side, and I never got around to it...

Bust_A_Cap

Wed Jun 25 2008, 12:46AM

Registered Member #1561 Joined: Mon Jun 23 2008, 07:58PM
Location:
Posts: 25

so a quick question, are you using the disposable camera as an actual camera? or just for the flash?

Hon1nbo

Wed Jun 25 2008, 01:40AM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: Pacific Northwest USA
Posts: 1042

Bust_A_Cap wrote ...

so a quick question, are you using the disposable camera as an actual camera? or just for the flash?

just as the flash, and I am moving on to dedicated flashes, however: I have decided to keep the disposable flash for capturing a secondary point of the event (only good for B&W film or tinted color...)

Hon1nbo

Thu Jun 26 2008, 10:54PM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: Pacific Northwest USA
Posts: 1042

[updated]
[updated again]
[pics added]

Hon1nbo

Fri Jul 04 2008, 12:43AM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: Pacific Northwest USA
Posts: 1042

[updated 07/03/08]

Bob123

Wed Aug 06 2008, 01:45AM

Registered Member #1626 Joined: Wed Aug 06 2008, 01:30AM
Location:
Posts: 2

It looks like I've been planning to build almost the same thing. However, I've just been acquiring my parts up to now and playing with the Arduino. Do you anticipate posting your project details and code at some point? Looking forward to seeing how your project turns out!
Bob

Hon1nbo

Wed Aug 06 2008, 02:31AM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: Pacific Northwest USA
Posts: 1042

since my last post I have had a lot going on, and it came down to not enough time to finish... once two-a-days are over, and school starts (surprisingly more time, especially with activities periods, double lunches (surprising amount), and weekends that are not over crowded with other nonsensical things... I will post the code as far as I got, it should work except some basic debugging like the value for modifying the value of the Potentiometer to something useful for delays, but the LCD code is not ready... but if you can make it work fell free to share ^_^
another setback was the loss of my small mic premamp that was going to set off the SCR, so I am temporarily using a guitar amp (which defiles the point of a remake of my High Speed setup)...
remember, I have not implemented some of the code for different sensors, but that is on the way... and realizing the rules of not posting of a direct how-to, here is what you need to know to get started (it helps to at least start out yourself, so you understand the code):

you will need serial enabled;
you will need an analog pin and at least 5 digital pins (if you use the Serial LCD though the Rx pin, I recommend it as it uses much fewer wires, and makes the LCD connection cable far thinner and more flexible), one for the SCR driving transistor, and the other three for setting a delay. the analog pin is for the sensor input.
a Potentiometer (I think 10K is what I had planned, but I used a 1 MEG b/c of the guitar amp) for the sensitivity;
an SCR rated for the load of the flash (typically 400V for a dedicated flash, maybe 500V... try to use an old flash as it will have a shorter duration)
a basic NPN transistor that will take the output of a digital pin from an arduino and set off the SCR (DO NOT directly connect an SCR to an arduino... the voltage spike at the gate will render the pin UNUSABLE!)

on the matter of sensors, I did not make the arduino select them: rather, I used terminal blocks and built the necessary modifications of the circuit for that sensor into the cables, so I did not have to add the load of the circuitry when I did not need them, and they are still swapped out quickly.)

as for Power, for the non-arduino parts used two AAs and the battery compartment that was in the case I bought... The arduino actually hooks in through one of the terminal blocks so that when it is not needed (like when I use the speed of sound for a physics demo) the extra weight is not there...

Also, since I decided it was unsafe to use the exposed terminal blocks for the flash, I used some two conductor cable, with a two pin-one way connector on the ends, so it can be extended and the flash can be safely detached

for the flash adapter, just splice into a Hot Shoe to a PC connector meant for flash sync with the camera.

this should be enough to get you started on the hardware side, but here is some software tips:

set the arduino to initially ask for the delay, and make it be set from two momentary buttons (I nixed the membrane keypad as it was touchy, and the arduino would have issues with it, and the transistors needed to make it work were bulky) and each button will increase or decrease the delay, then press the third to "lock" it in until it is reset...

the arduino then will have the sensor connected to it through a Potentiometer and an analog pin (the value of the analog pin may vary, and the software may have to modify it some to make it usable)...

once the delay is set, the arduino will start a secondary loop (since the main loop is not running in this case, you can make things work a little faster, so the 16Mhz is better used to make a fast timer)... this loop will look for the threshold value to be broken by the sensor pin value, then set the SCR driver pin to HIGH for a few moments, then turn it off, and it is good to make it wait a minute so that it will not go off again before you can close the shutter...

The LCD I did not get to work (using Serial at least, which killed the old version along with rushed craftsmanship), but someone who has the time can get it done easily...

hope this helps, and once I have time again I will get some good pics!

good luck!

Bob123

Wed Aug 06 2008, 08:28AM

Registered Member #1626 Joined: Wed Aug 06 2008, 01:30AM
Location:
Posts: 2

Thanks for your kind thoughtful reply. i'll proceed and let you know how it works out. I may end up using a different controller due to the limited EEPROM of the Arduino. I don't like to be limited in my headroom at the onset. But, we'll see, the challenge of a very small processor is appealing.
Best, Bob

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