Author Topic: High Speed Photography (Read 7349 times)

DennisW · « **on:** August 21, 2012, 09:08:28 am »

How about putting a micro USB connector and mic sensor on one of the shields to trigger a flash with a balloon pop or some other loud noise?

Other kids use stereo jacks but I think the footprint is way too big. Is there a through hole usb connector? Or would it need to be the SMT shield?

I was thinking mount the sensor on the shield and use a micro usb cable send the signal to the flash when a loud sound is made using a PC sync cable. I don't believe there are any PC sync to micro USB. However a micro usb to stereo can be picked up cheaply. and stereo is the common connector used.

Second idea

using a phototransistor and a micro usb connector. This one can be used to detect Lightning. The usb connector can be connected to the camera using a camera cable. so when the flash is detected, the camera takes a photo. I do believe an optoisolator would be needed to isolate. But can a micro usb, 4 pin optoisolator and a sensor all fit on one shield?

MichaelMeissner · « **Reply #1 on:** August 21, 2012, 10:24:56 am »

For camera control, you often want 2.5mm jacks because you can commonly get cables for Pixel wired shutter releases that attach to various cameras, and you don\'t have to muck about creating a camera specific cable (others might use 3.5mm jacks). You can also get a pc-sync to 3.5mm cable fairly easily. However, if you are handy with a soldering iron, you can always slice open a cable, and make your own connection.

One of the uses I plan to do with the digispark is to redo my telegraph shutter release to make it smaller. I put a picture of it on the Arduino exhibition forum: http://arduino.cc/forum/index.php/topic,117629.0.html

There are two commercial companies that are using Arduinos to provide various triggers for high speed photography: http://www.cameraaxe.com/wiki/index.php?title=Main_Page and https://triggertrap.com/

Both should have how-tos on how to trigger the flash.

I don\'t think you really don\'t want to use the USB port. Instead you want one of the pins on the digispark to connect to an opto-isolator, which you can mount on the shield. Then you want to connect your pc-sync cable (either hacked by you, or via a 2.5mm/3.5mm jack) to the opto-isolator.

The reason is, you don\'t want the Arduino electrically connected to the flash. An opto-isolator is a electrical chip that has at least 4 pins. When a circuit is made between the two input pins, it lights up a LED inside of the case, and then a photo-resistor completes the circuit for the 2 output pins.

In terms of 3.5mm jack, I just bought the following from ebay, and with a 5 pin header, it will mount in a standard breadboard, but you could use the screw mounts to connect the wires: http://www.ebay.com/itm/300655692210?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

I also bought some 2.5mm surface mount jacks, but I\'m still waiting for delivery from China: http://www.ebay.com/itm/180898083343?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

At the local electronics store, you can get both 2.5mm and 3.5mm with terminals for soldering.

Here is a picture I took to remind myself how to connect the opto-isolators I\'ve bought: http://www.the-meissners.org/2012-small-albums/2012-arduino/thumb/2012-07-16-08-25-004-arduino.jpg

DennisW · « **Reply #2 on:** August 21, 2012, 10:44:38 am »

my thoughts was to use the micro usb because of the physical size of the shields of this device. A 3.5 or 2.5 jack would take up a lot of space I would think. whereas we could put a micro usb on the board. use a micro usb to stereo cable and still keep the normal cables intact. This keeps the device very small just adding the additional bulk on the cable vs the board. And I was thinking of putting the isolator between the digispark and outpin of the micro usb.

micro usb to stereo

http://www.amazon.com/Samsung-Headset-Adapter-to3-5mm-Female/dp/B003W057FS/ref=pd_cp_cps_0

http://www.amazon.com/gp/product/B002HRE64K/ref=s9_simh_gw_p107_d0_i1?pf_rd_m=ATVPDKIKX0DER&pf_rd_s=center-2&pf_rd_r=0QE8CTKAT270YFPEKR0M&pf_rd_t=101&pf_rd_p=1389517282&pf_rd_i=507846

MichaelMeissner · « **Reply #3 on:** August 21, 2012, 11:15:52 am »

Ok, I misunderstood you. I thought you were wanting to use the main USB stick for programming, and not a secondary mini-USB. That would mean you would have to power the unit via the VIN/ground pins, and it would complicate debugging and downloading new code.

I didn\'t know they made micro-usb to 3.5mm jacks. For pc-sync, I would be tempted to forgo the jacks all together, and just slice up a pc-sync cable, and wire it directly into your opto-isolator. For camera control, depending on the camera, you need a specific cable. You could slice up one of the cables, but for now, I\'m using the jack, in part because I use 2 different cameras with different camera cables.

In my telegraph shutter release, I had the 2.5mm mount next to the breadboard and wired the bottom two wires to go through the proto-board under the breadboard to hold it in place, and it should fit easily on the through hole shield, probably using 3 holes by 3 holes. You can\'t really see it in this image: http://www.the-meissners.org/2012-large-albums/2012-arduino/large/2012-08-05-23-36-011-arduino.jpg

I don\'t have a part number for the unit I was using (I bought it at the local electronics store), but this part from Radio Shack is similar: http://www.radioshack.com/product/index.jsp?productId=2103450

DennisW · « **Reply #4 on:** August 21, 2012, 11:49:32 am »

Using the micro usb shouldn\'t mess up the debugging or downloading new codes because I would only be using the micro usb for a transport only and not for usb communication. I would hook up the 5 v, GND, and one digital pin. Once the sensor is triggered, the digital pin would go high and either trigger the flash, or shutter depending on which I was doing. I picked the Micro usb as my connector because it is rated to be unplugged and plugged in about 10,000 times. Pretty much the same as using a stereo jack a very small footprint. And since the digispark is only 19x17.5mm or 19x16.5mm. it wouldn\'t leave much room left if we used a 3.5mm jack.

bart · « **Reply #5 on:** August 23, 2012, 01:24:14 pm »

chibi · « **Reply #6 on:** September 15, 2012, 10:04:12 am »

I have an Arduino camera trigger shield and could make a Digispark shield if there is enough interest.
I would think that one shield for the opto-isolated camera output and another one for an audio trigger. Any ideas?

MichaelMeissner · « **Reply #7 on:** September 15, 2012, 10:50:52 pm »

Why two separate shields? I would think you would want only one.

chibi · « **Reply #8 on:** September 21, 2012, 09:23:32 pm »

Since some people may want something other than an Audio trigger or Camera / Flash control; keeping the functions separate allows flexibility to design their own trigger, such as an Audio trigger, a Laser trip wire or any other trigger method they want to utilize. Additionally, you can have multiple isolated cameras controlled off a single trigger method.