Flash/Camera Trigger Thing

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Texy

Senior Member
Phil I know it will vary considerably with each setup what what is a typical starting delay (after the IR trigger).
Texy
 
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styrophil

Member
My rough starting point is that for a drop of about 50cm I start with 0.3 seconds.

If you set everything up and but some black paper/card up as a background you can normally see the drop of water if you watch carefully. make sure you are looking for the drop from behind the flash so that it doesn't fire straight in your face. With water drops you are probably looking at adjusting the tenths and hundredth of a second digits, any finer adjustments than that is not going to make much difference.

For the photos above it took me about an hour to get the timing right.

As you say it depends greatly on your setup. With drops of water timings can be dependent on so many things you just need to take the time to get it right.
 
T

Texy

Senior Member
I,ve still got a few things to do, like fit the LED's and put it in a nice box, but mine is more of less, done. I,ve yet to use it in anger however, only on the bench. My primary use will be with the high speed flash option, and that appears to be working well as far as detecting water droplets and firing the flash is concerned.
I do have a problem with the camera trigger on the other options. For example, with the interval timer, the camera will only take a picture on the first instance, after that it will not take a picture. I,ve tested the camera and cable, and if I use a wire link to short out the connections, then all is well, so I,m guessing the the problem is with the opto circuit. How critical is the 330ohm series resistor, as I used what I had available - a 270ohm ?
Earlier on, when the opto's first arrived, I experimented with driving an LED, and I found the problem in a slightly different way - the LED would come on when requested, however, it would stay lit until power was removed, not when the logic input was toggled. I put this down to the LED maybe keeping the SCR on somehow, but now I,m not so sure.


Incidently I also (as planned) did away with the lcd driving chip and wired the
lcd directly to unused port B pins. Because of the way I bit-bang the 4 bits required, I had to re-assign register b0. Apart from that it wasn't too much trouble, although every instance of 'serout' had to be replaced with my own code. Looking forward to giving the water droplets a go later.

Texy
 
P

papaof2

Senior Member
Texy said:
Earlier on, when the opto's first arrived, I experimented with driving an LED, and I found the problem in a slightly different way - the LED would come on when requested, however, it would stay lit until power was removed, not when the logic input was toggled. I put this down to the LED maybe keeping the SCR on somehow, but now I,m not so sure.
Texy
Click to expand...
The gate on an SCR can turn it ON but not OFF. Once turned on in a DC circuit, an SCR stays on until the voltage across it drops below the minimum conductance voltage (very close to zero volts). This isn't a problem in AC circuits because the voltsge goes to zero at the mains frequency (50/60Hz).

If there is a small residual voltage across the SCR after the initial firing, it will stay on.

Maybe a place for a MOSFET? Can be turned on and off and they are available with 600 volt ratings.

John
 
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styrophil

Member
Texy said:
I do have a problem with the camera trigger on the other options. For example, with the interval timer, the camera will only take a picture on the first instance, after that it will not take a picture. I,ve tested the camera and cable, and if I use a wire link to short out the connections, then all is well, so I,m guessing the the problem is with the opto circuit.
Click to expand...
I had exactly the same problem with my test setup. I doubt (although I could be wrong) that it's the circuit. I found that I needed to alter the amount of time that the isolator was triggered.

let pinsA = %00000101
pause 500
let pinsA = %00000000

Try changing the pause command to a higher value or start at something like 2000 and work down.

Don't forget that the above section of code appears twice, at both the beginning and end of the interval_timer routine.
 
S

styrophil

Member
Texy said:
I put this down to the LED maybe keeping the SCR on somehow, but now I,m not so sure.
Click to expand...
I've just re-read your post. Are you using a SCR to trigger the camera or are you using the opto isolater that I used in my version?

If you are using a SCR then I expect that it is your circuit. I tried various types of SCR with no joy when it came to triggering the camera.
 
T

Texy

Senior Member
Phil,
I've made no change to the circuit - the camera is driven directly via the opto isolator. However I believe that thenopto isolator's output is indeed an scr? Could be wrong! I'll
give the timings a tweak tomorrow and let you
know how I get on.
Incidently do you know if anyone else has built the phifact?

Cheers texy
 
S

styrophil

Member
Texy said:
Incidently do you know if anyone else has built the phifact?
Click to expand...
Not as far as I know. No comments on the blog so far (feel free to add a comment).

I took it along to show several photographers last week and there was a lot of interest, but it's a matter of finding the people who actually want one and have enough confidence to get out the soldering iron!
 
S

styrophil

Member
Datasheet for the MOC3020 is here...

http://www.farnell.com/datasheets/94947.pdf

Texy, Just had another though about the camera triggering. Make sure you have your camera/lens set into manual focus or the pulse from the trigger will activate the autofocus and, if the camera does not focus before the end of the pulse, the shutter won't fire.
 
T

Texy

Senior Member
styrophil said:
I had exactly the same problem with my test setup. I doubt (although I could be wrong) that it's the circuit. I found that I needed to alter the amount of time that the isolator was triggered.

let pinsA = %00000101
pause 500
let pinsA = %00000000

Try changing the pause command to a higher value or start at something like 2000 and work down.

Don't forget that the above section of code appears twice, at both the beginning and end of the interval_timer routine.
Click to expand...
Right, managed to spend a little more time on this. Unfortunately, the above code change has not fixed the problem. I,ve noticed the following :
The voltage across IC2 pins 4 and 6 at camera switch on is 5.2 volts.
When the phifact has successfully triggered the camera the voltage quickly goes down to 0 volts, and then goes up to 0.78 volts. Whilst it is at that voltage the camera cannot be triggered externally. If I then manually take a shot, the voltage goes back up to 5.2volts, and with the next trigger from phifact, it successfully takes another shot. It would be interesting to know how your canon behaves, and also if you have used a nikon, how you got on with it.
I also noticed that when using the IR trigger, that the flash would only trigger when connected to the camera output, not the flash output. If I,m reading the code correctly, and the flash is triggered via the Interrupt routine, then the code should be changed from

Code: 
interrupt:
 let pinsA = %00001000
 pause delay_ms
 pauseus delay_us
 let pinsA = %00000101
 pause 500
 let pinsA = %00000000
 hint0flag = 0 
 setintflags FLAG_DETAILS, FLAG_DETAILS
return
to

Code: 
interrupt:
 let pinsA = %00001000
 pause delay_ms
 pauseus delay_us
 let pinsA = %00000011
 pause 500
 let pinsA = %00000000
 hint0flag = 0 
 setintflags FLAG_DETAILS, FLAG_DETAILS
return
Note that I still do not have LED1 or LED2 fitted yet, so there may be other tweaks to the code (if they are meant to light momentarily when either the camera, or flash are triggered). I,ve made the above changes to the code here, and it is now working as expected.

The next step is to experiment with a FET - I have a few 2N7000's here from my RC Camera shutter days.
Cheers,
Texy
 
S

styrophil

Member
Texy,

In reverse order...

The code and the description I posted may be a little at odds. The code that I wrote only triggers one output regardless of the program. You connect either a camera or a flash to the port depending on what you are doing. The second port is there in case you want to write a program which triggers two flashes/cameras or one of each. If you connect up the LEDs then when you get the message "Connect camera - press any key" then the appropriate LED lights up to indicate the socket. Naturally you can change this in your code so that there is one socket for a camera and another for a flash. I see that I left the words "to camera" and "To flash" on the circuit diagram and I'll change that at some point so it's not confusing for anyone else.

Yes the LEDs are meant to light momentarily to indicate when an output triggers and one of them is also used to indicate a countdown in the "Bulb Timer" mode.

I did try one of the Nikon D50s at work and it seemed fine but I had to borrow a cable from a friend and did a rather intelligent hack on it as I had to hand it back in original condition. How are you connecting your camera to the circuit? Can you post a pinout diagram for the cable and I'll check it next week when I can get hold of the cable again.

You mentioned that you changed the circuit so that you didn't use the FRM010. Can you post a link to your circuit diagram and a copy of your code and I'll see if I can duplicate it here.
 
T

Texy

Senior Member
Well I have done a certain amount of guess work;)
Yes I took the labels on the circuit diagram to mean thats how to connect the camera and flash, I didn't know that only one or other was intended to be connected at any one time. However, I like the seperate arrangement,
so thats how I,m leaving mine:D.
This is how the LCD is connected - the pins are all port b :

SYMBOL RS = 1 ; 0 = Command 1 = Data
SYMBOL E = 2 ; 0 = Idle 1 = Active
SYMBOL DB4 = 4 ; LCD Data Line 4
SYMBOL DB5 = 5 ; LCD Data Line 5
SYMBOL DB6 = 6 ; LCD Data Line 6
SYMBOL DB7 = 7 ; LCD Data Line 7

One other thing I,m not sure about is - what is 'delay shift' ?
I would also like to see a countdown on the LCD when using either the interval timer or the bulb timer.

There should be two attachments with this posting.

Texy
 

Attachments

T

Texy

Senior Member
2nd two attachments

The cable is made from 3 wires - focus, shutter, and ground.
Cable was cut from an ebay cheapo shutter release cable - the focus and shutter wires have been connected together at the camera end connector. so that makes now makes 1 wire, the other free wire (ground) in the cable makes the other line - when these two lines are shorted, the camera is triggered. Just a reminder that if I physically short these two wires together, the camera will trigger every time, so I am happy the cable is wired correctly. Hope that makes sense!

Cheers,
Texy
 

Attachments

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S

styrophil

Member
The "Delay Shift" lets you increment and decrement the flash delay whilst the trigger is running. So...

Enter your best guess by pressing the star key.

Then press the hash key to enter the "Delay Shift" routine.

Use 1 & 7 to go up and down in 1/10 second jumps
Use 2 & 8 to go up and down in 1/1000 second jumps
Use 3 & 9 to go up and down in 1/100000 second jumps

The code doesn't roll over. Writing better code is left as an exercise for the reader! Then again I'll probably look at it myself once I've finished writing the building instructions.

I'm going to be marking resits from tomorrow so it might take me a few days before I can have a proper look at your code.
 
T

Texy

Senior Member
Had a quick play with a 2n7000 this evening - the camera works fine with it, both with interval timer, and in bulb mode:).
I think I,ll leave the opto in place for the flash, and the FET for the camera.
I just need to fit the leds and put it in a nice box, then it'll be time to get the bowl of water out.

Texy
 
G

g6ejg

New Member
There is actually an interesting related project to this one. I came across this picaxe thread last night then started hunting around for a cheapo remote flash unit. I then sat wondering if there was anything I could do with the inbuilt flash unit of two old camera's sat in the loft. A bit more hunting around and I came across this project:-

http://www.diylive.net/index.php/2006/03/16/diy-disposable-camera-flash-slave/#comment-42054

(actually I came across a few similar ideas but this was about the best write up)

Basically the author has hacked the flash unit of a disposable camera such that a photosensor detects the flash from the main flash gun and uses it to trigger the slave flash made from the disposable. seems to me that this is a perfect extension to this project (ie using the picaxe to trigger the disposable camera flash instead of a photosensor) and would allow you to have as many flash units as you like for just a couple of pounds.

Alternatively my next stop is the local chemist with a photo lab to see if they have any used disposables that they are throwing away/recycling - slave flashes for virtually nothing in that case!
 
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T

Texy

Senior Member
1st session

Finally got round to trying this. Still got a long way to go but here are a few pictures from my efforts so far :






Texy
 
T

Texy

Senior Member
Well this thread died very quickly didn't it, which I,m surprised about TBH.
Anyway, no apologies for the resurrection!

Now that the darker nights are fast approaching, I,m going to be using the 'thing' again.
However, I,m planning on modifiying the hardware to control the water drops using a solenoid valve and a spare output. Actually I can't remember if there is a spare output, as I used the 28X2 to drive the LCD directly instead of the LCD driver chip, LOL.
Anyway onto the point of this post - can anyone suggest a suitable cheap soleniod to use? From another site I found this :
http://www.solenoid-valves.com/Page1.htm
However they want around £30 for it, and I,d prefer to spend less if possible. This same supplier does have a nylon version for only £15, but needs 24volt for the coil, 12volt would be much more convienient.

Rgds,
Texy
 
D

Dippy

Moderator
It lasted 3 weeks so that's not bad is it? :)
And you showed us some very nice pictures.

Perhaps if you specified a pressure rating and preferred connector type then people may be able to spend some time looking around for a suitable device.

What about the water valves used in Washing Machines, Dishwashers etc.? Any joy in a spare parts shop or pinching a bit from Mum's machine without telling her?
 
S

styrophil

Member
I must apologise for the lack of updates on this. As with so many things life sort of got in the way and I've had no time to spend on this at all.

I did have a conversation on Flickr with a guy who built one of these units and a number of issues cropped up...

There is an issue with the MOC2030 opto-isolator. It works just fine and dandy with some cameras but not others. There is a replacement part - not quite pin for pin. I'll look up the details and post the details.

The interval timer code needs to be reworked. The timer works just fine but if you set a large number of shots then the counter keeps rolling round and the thing just never stops. Not a killer but it needs fixing.

The site with the info - I never did get around to writing the building instructions and it's been so long now that I need to start from scratch. The other issue I had was that I was getting 100-200 spam comments a day on the site so it was impossible to find the real comments and I ended up turning the commenting feature off.

I have been thinking about a water droplet timer add on. Particularly for those water droplet collision photos. My big problem with this is the mechanics so if anyone has any ideas about solenoids or suitable pumps then I'd be interested too.
 
techElder

techElder

Well-known member
In an industrial setting, I have used a hobby servo with a roller on the arm to 'squeeze' a drop of liquid out of a flexible tube that had an orifice attached to the end of it.

The servo position/timing could be adjusted for various effects.

It was a quite repeatable operation.
 
T

Texy

Senior Member
Well I haven't lived with mummy for over 25 years, but thanks for the suggestion:rolleyes:

Pressure needs are very low - this is only to allow a single drop of water at a time. The type used for the same purpose was type PU22002A on the link above.


I,m just looking for a cheaper supplier if possible:)

Texy
 
T

Texy

Senior Member
Texasclodhopper said:
In an industrial setting, I have used a hobby servo with a roller on the arm to 'squeeze' a drop of liquid out of a flexible tube that had an orifice attached to the end of it.

The servo position/timing could be adjusted for various effects.

It was a quite repeatable operation.
Click to expand...
Good idea, but just wouldn't happen fast enough for this purpose, I think.

Texy
 
techElder

techElder

Well-known member
All you're doing is creating a drop with the servo system. We could even adjust the size of the drop. The adjustable nature of it comes in when you use different fluids with different densities.

Photos of plain old water drops are boring. Change the viscosity of the fluid, and you're going to get more interesting photos.

'Nuff said.

Texy said:
Good idea, but just wouldn't happen fast enough for this purpose, I think.

Texy
Click to expand...
 
T

Texy

Senior Member
That's fine for single drop of liquid, but for the collision shots, you need two quick drops one after each other, with nothing before or after (at least for a while). Its the critical time in between the two drops thats important, and I don't think a servo will allow the accurate finite time measurements needed. However, I could be wrong!

Texy
 
premelec

premelec

Senior Member
A rubber bladder, diaphragm or pipe pulsed with a solenoid [capacitor discharge...] could give you some short and well controlled squirts for cheap... there are small solenoids in old zip drives and hard drives that could be salvaged or you could try relay armatures which also abound - just reduce it to the mechanical part of the relay and strip the contacts... and keep the coil.
 
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