[TeamPentax]

Yes excellent results

Now all you need is a direct hit and to get the DeLorean up to 88mph and we can all go back to 1985!

Ok, let me set up my tripod before you start the car !!!!

[TeamPentax]

There is no need to "take anything apart" all pentax DSLRs have a wired release using a 2mm 3 connection headphone plug. The reason for using a photo diode is because there is no need to supply current, the camera's shutter release circuit does this by way of a resistor in series with the release contact. It is looking for a short to the common to trip the shutter. As for functionality the scheme works and using a commercial plash slave (schematic shown above) it os possible to trip the shutter with a camera flash. To create a lightning trigger simply requires changing the base emitter resistor to reduce the current necessary to turn on the transistor i.e. To increase the sensitivity. Too many people are looking for a complex solution when using these three simple components is all that is needed

True , no need to take anything apart, I actually scabbed some parts from old photo gear and have added it to the shutter release cable , I can get it to fire one shot with just the photo diode & resistor attached with a flash, then it won't fire again ?

When I put in the transister it just trips the circut and it just continuously shoots so now my question is with all you very intelligent people joining in, what sort of resistor ? give me a code , they run in code from the colors on them, as I'm sure you all knew this 10 years ago which I only found out 3 days ago, and also the transistor, may be a code number to go for that to, I go into a electronics shop and explain to them what I'm trying to achive and then they look at me like "are you ET" so the staff in these shops usually can't count their elbows and get the same answer twice so getting their advice is pointless. I go look at the hundreds of trays containing just resistors and I'm like.....which one ?

As I've said I made it trip one photo with a off camera flash so I now know it can be done all I need is the right parts / ingredients.

Someone said I should use a IR diode, is that a better idea than a photo diode ?
Also is there a way I can put in a pot switch so I can change the sensitivity of the Diode on the run ? So if it misses a shot of lightning a can turn the pot and wait for another chance so I can set it up for what ever situation I might be in.

I only have the idea,, but the how to is beyond me.

if I can finally get a prototype up and running I'll do full sketches and even a youtube video so everyone that has the 2.5mm jack can make one without paying through the nose.
Yeah I know i could buy one, but wheres the fun in that ? I'd rather buy a lens, I only have the one !

I was thinking I could put a 2.5 mm jack onto the homebuilt shutter release then I can attach it as an accessory so I can use it when I want without having it on all the time.
Some say to put the diode on the eyecup so it see's what the camera see's, I like the hotshoe my self but what ever works best WINS !!!! I can make both, have 2 Diodes the ideas are endless, the knowledge... is hungry for more !

Thank you to everyone again for all your help, I really appreciate it and as I've said before, once completeted I'll put back in here so everyone can have a go, it's only held back by our imagination !

[TeamPentax]

*istD does not have ISO modes, ISO is set once for all modes.

I know what you mean with later cameras, K10D can have at least 3 different ISO settings as a function of mode used. Manual is one, User is a second, and you can have the auto modes set to Auto ISO. I have not looked to see if Bulb has an independant setting of its own on the K10D.

There you go, you've answered my question before I even asked it !

Thanks a hell of a lot !

[Lowell Goudge]

True , no need to take anything apart, I actually scabbed some parts from old photo gear and have added it to the shutter release cable , I can get it to fire one shot with just the photo diode & resistor attached with a flash, then it won't fire again ?

When I put in the transister it just trips the circut and it just continuously shoots so now my question is with all you very intelligent people joining in, what sort of resistor ? give me a code , they run in code from the colors on them, as I'm sure you all knew this 10 years ago which I only found out 3 days ago, and also the transistor, may be a code number to go for that to, I go into a electronics shop and explain to them what I'm trying to achive and then they look at me like "are you ET" so the staff in these shops usually can't count their elbows and get the same answer twice so getting their advice is pointless. I go look at the hundreds of trays containing just resistors and I'm like.....which one ?

As I've said I made it trip one photo with a off camera flash so I now know it can be done all I need is the right parts / ingredients.

Someone said I should use a IR diode, is that a better idea than a photo diode ?
Also is there a way I can put in a pot switch so I can change the sensitivity of the Diode on the run ? So if it misses a shot of lightning a can turn the pot and wait for another chance so I can set it up for what ever situation I might be in.

I only have the idea,, but the how to is beyond me.

if I can finally get a prototype up and running I'll do full sketches and even a youtube video so everyone that has the 2.5mm jack can make one without paying through the nose.
Yeah I know i could buy one, but wheres the fun in that ? I'd rather buy a lens, I only have the one !

I was thinking I could put a 2.5 mm jack onto the homebuilt shutter release then I can attach it as an accessory so I can use it when I want without having it on all the time.
Some say to put the diode on the eyecup so it see's what the camera see's, I like the hotshoe my self but what ever works best WINS !!!! I can make both, have 2 Diodes the ideas are endless, the knowledge... is hungry for more !

Thank you to everyone again for all your help, I really appreciate it and as I've said before, once completeted I'll put back in here so everyone can have a go, it's only held back by our imagination !

Not to be rude here, but you are asking people to do design work on this, and to teach you how to do design work.

In the circuit I posted, what is shown as a transistor is actually a thyristor, I took the time to look this up on the web

the data sheet is here

CR02AM-4 pdf, CR02AM-4 description, CR02AM-4 datasheets, CR02AM-4 view ::: ALLDATASHEET :::

the principle for trigger is the same however, the only difference is the thyristor will stay triggered as long as current continues to flow once it is turned on.

the resistor is 20,ooo ohms.

resistor codes are as follows for the color bands

Black = 0
Brown = 1
Red = 2
Orange = 3
yellow =4
green = 5
blue = 6
violet = 7
grey = 8
white = 9


The code is as follows.

You will have a number of bands on the resistor, AND the sequence is important. One band will be further away from all the others, and this is the tolorance band if present. The bands will also be offset to one side.

With the group of bands on the left. and reading left to right, you will have potentially 3, 4, or 5 bands

if they are called ABCDE the coding goes as follows.

3 bands
A.B times 10 raised to the power C for 3 bands, 10% tolorance

4 bands

A.B times 10 raised to the power C, with the 4th band being tolorance, usually Green for 5% or red for 2%

Once you get to 1% or lower tolorance there would be 5 bands
A.BC times 10 raised to the D power with E% tolorance.

so the code in general is that the last band is tolorance, the first band is the only digit to the left of the decimal sign, and the second last digit is the multiplier

As to the values of components you need, this is where there will be some need for expeimentation.

I can't tell you how much light it takes to trigger the photo diode, how much current it takes to turn on the transistor or thyristor, and how sensitive you want the circuit.

[Ex Finn.]

Someone... build one ,will you..

[Ex Finn.]

I am a visual guy, here, courtesy, Leon Audio.

[TeamPentax]

Another technique to photograph lightning in the daytime is to use a filter. Years ago, I used an automated 35mm film camera with a 180-degree fish-eye and an infrared filter as part of a lightning investigation on power lines. Lightning has very strong light emissions in the infrared spectrum (especially hydrogen-alpha). I currently use an inexpensive infra-red filter that enables 15 to 30-second daylight shots.

Triggers that use the electric field change from lightning are preferable to optical triggers if you want to capture the early part of a flash (all those pretty branches!). The optical triggers work fine, but you'll generally only capture subsequent strokes in a multi-stroke flash. Good for engineers, but not so good for artists!

Mike

(who plays with lightning for a living)

What nm filter do you use, theres quite a few, as far as I can see from 680nm to 1000nm, there might be more but I hadn't heard of this filter before.

Thanks for the idea, do you have any photos of the results of this method because it sounds very interesting and would like to see your results if possible.

[TeamPentax]

Not to be rude here, but you are asking people to do design work on this, and to teach you how to do design work.

In the circuit I posted, what is shown as a transistor is actually a thyristor, I took the time to look this up on the web

the data sheet is here

CR02AM-4 pdf, CR02AM-4 description, CR02AM-4 datasheets, CR02AM-4 view ::: ALLDATASHEET :::

the principle for trigger is the same however, the only difference is the thyristor will stay triggered as long as current continues to flow once it is turned on.

the resistor is 20,ooo ohms.

resistor codes are as follows for the color bands

Black = 0
Brown = 1
Red = 2
Orange = 3
yellow =4
green = 5
blue = 6
violet = 7
grey = 8
white = 9


The code is as follows.

You will have a number of bands on the resistor, AND the sequence is important. One band will be further away from all the others, and this is the tolorance band if present. The bands will also be offset to one side.

With the group of bands on the left. and reading left to right, you will have potentially 3, 4, or 5 bands

if they are called ABCDE the coding goes as follows.

3 bands
A.B times 10 raised to the power C for 3 bands, 10% tolorance

4 bands

A.B times 10 raised to the power C, with the 4th band being tolorance, usually Green for 5% or red for 2%

Once you get to 1% or lower tolorance there would be 5 bands
A.BC times 10 raised to the D power with E% tolorance.

so the code in general is that the last band is tolorance, the first band is the only digit to the left of the decimal sign, and the second last digit is the multiplier

As to the values of components you need, this is where there will be some need for expeimentation.

I can't tell you how much light it takes to trigger the photo diode, how much current it takes to turn on the transistor or thyristor, and how sensitive you want the circuit.

Believe me this is not my intention, I just wanted to pick some more knowledgeable people'a brains so I could make one.
My intention is not to ask people to design one, just to help me build one, to tell you the truth I thought someone out there had already experimented with this and was hoping that some one would say that you use this kind of resistor and this photo/IR Diode and that kind of thyristor. With your diagram I'm able to build it, it's just the amount of different types of the same component that throws me.

I do thank you for all your detailed information it really helps and I really appreciate it.

[Ex Finn.]

Radio-shack used to have this great little series of books available. The Engineer`s mini note book, they covered all kinds of circuits in a practical and easy way of understanding.Amazon.com: Engineer's Mini Notebook: Op Amp IC Circuits: Forrest M. Mims: Books
They had the OP-amps, 555 timers, transistors and such explained pretty well.
Also provided was a boat load of practical circuit schematics with Radio-shack part numbers.

[Ex Finn.]

They still make them/ have them available, the modern version`s.
FORREST MIMS GETTING STARTED IN ELECTRONICS | BOOKS | ELECTRONICS | SCIENCE FAIR PROJECTS

[TeamPentax]

Here is one I took a few weeks ago. Using a K200D with kit lens.

f/5
23.3 second exposure
ISO 100

I was using bulb mode with a remote, and it was an intense lightning storm. I would open the shutter then close it everytime I saw lightning strike. Worked quite well.

sweet shot, did you have DFS off or on ?

[TeamPentax]

So I've spent a small fortune on trying to build a lightning trigger and had mixed results, I could get it to go off but once it did it wouldn't again, no matter how I put it together so I'm giving up.

I got one the old fashioned way.

Thank you for everyones help, I really appreciate it.

[tonyriddle]

Hi,

i have been looking for a lightning trigger for quite some time. The followings seem the optimal ones in terms of cost and quality.

The expensive one which seems more professional:
Lightning Trigger

The cheaper one which has lots of positive feedbacks on ebay:
Lightning Trigger

Any feedback will be really appreciated from those who have experience with them.

Tony