Pencam applications in rockets

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BlueNinja

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I am probably going to order a pencam tonight (Aiptek pencam II) and was looking for suggestions on how to mount it to the rocket and how to rig it to take a picture every (x) second. I am thinking about flying it in a stock Deuce or Tres.

I will be buying it from ebay.
 

Mike

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There are two main methods of getting a camera to take pictures, either with a servo or electronically.

With a servo you need to modify the servo so that it completes a full rotation (I've heard it isn't too hard) and then make a mechanism such that the shutter button is pressed as the servo rotates.

To control the pencam electronically you'll need to solder two wires into the shutter button, these can then be linked to a relay and a timer circuit can be used to control it. You can buy pencam controllers which give you a lot more scope than a simple timer circuit.

If you search the forum you'll find a lot of people using Pencams in their rockets.
 

BlueNinja

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Thanks for the help. I've heard that the driver is not windows logo tested, is this a problem that will mess up my computer?
 

Mike

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I acctually don't know, I've never used a Pencam so couldn't say. The info above was based on what I've read around the forum and through making a 35mm camera rocket.
 

BlueNinja

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Could you provide a little more information on the timer route? That is probably what I will use for now.
 

Mike

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OK this is the route I've taken, but I'm sure there are other (probably better) ways of doing this.

For my 35mm rocket I wanted to take a picture every two seconds for one minute, that way I'd get 30 photos which is plenty to fill up a film.

I used 555 timer chips to do the timing, if you're not familiar with the 555 it functions in different ways depending how you connect it up. One is the monostable, it uses a 'trigger' switch and once it is triggered the output remains on for a set amount of time. You can change the amount of time by using different value resistors, there's a formula so you can work out precise values. Another mode of the 555 is an astable, this has no trigger but what it does is switch the output on for X amount of time then off for Y amount of time, again you can determine the values.

What I did for my camera controller is use an monostable and an astable. The monostable had a g-switch for the trigger and was set up so it stayed on for 60 seconds. I wired the output of this chip to the reset pin of the astable. For the 555 it will only work if the reset pin is receiving power, if there is nothing going to the reset it won't function. My astable timer was set up so it went on for one second then off for another.

When the rocket lifts off the switch is triggered, this turns the output of the monostable high, the reset of the astable receives power so the astable starts to do its thing. This is linked to a relay so the relay clicks on and off taking pictures. Once the sixty seconds is up the monostable turns off which makes the astable stop and no more photos are taken.

That was pretty long winded explanation, this website probably explains 555 timers better and gives you schematics for mono/astables.

https://www.eleinmec.com/article.asp?4

One little note about modifying cameras, they contain capacitors which remain charged even after the battery is removed and can give electric shocks so take care. I learnt the hard way.
 

SwingWing

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The AYUCR controller is a good unit to use. If you want to get a camera into the air without the hassel of designing your own, I would get one of these. I think you still have to solder it together.
If you want to dive into building your own timer, I also would suggest a LM555 based timer.
I used some of the circuits from this site.
https://home.cogeco.ca/~rpaisley4/LM555.html

My timer is based off the astable oscillator, using a 220microfarad capacitor, a 2kohm resistor for R2 and a 5Kohm potertiometer for R1. The power is supplied by a 12V "N" cell battery and the output is to the oil of a relay. the shutter is hooked across the normally open contacts of the relay. The circuit has an "arm" switch" and a pull pin trigger switch between the battery and the circuit.

A stock Deuces Wild may not have enough thrust for a pencam payload. I have launched my pencam in a scratch BT-60 3xC6-3 rocket that looks like a NCR Phantom and also in a 24mm upscale Deuces Wild 2" BT. I dunno if two 18mm motors would be enough oomph.

I have the camera and circuit mounted in their own payload bay, attached to some dowells that are embedded in the balsa bulkhead. My camera points out a hole in the tube, into a mirror (stolen from a makeup compact) and down the rocket side.
 
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