Vidcam project - help!

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vjp

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I'm converting one of those little $20 pencams from Wal-Mart into a "digital cineroc".

Anyone know of a creative source for small first-surface mirrors? Preferably something that doesn't have to be special-ordered - something lying around the house or available at Wal-Mart, for example.

(I'm trying to keep the project really, really cheap, and really, really easy, so I can post instructions which anyone can follow and make their own with minimal trouble & expense).
 

shockwaveriderz

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how about a dental mirror ? that you use to look at your teeth with? I have seen those both round and square-ish.....
 

eugenefl

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Originally posted by shockwaveriderz
how about a dental mirror ? that you use to look at your teeth with? I have seen those both round and square-ish.....
Those are actually too small to reflect the image. The mirror size has to be a few dimensions larger than the lens on the camera itself. (Ok, there's some basic science to this that I can't place my finger on, but trial and error has taught me what works and what doesn't!)

VJP, you may want to contact RayDunakin@aol.com - he's cut some custom mirrors for me in the past (I have some on order as a matter of fact). Drop him a line and see if he can assist. He had previously offered these mirrors on ROL probably over a year ago.

I've used a square mirror from a parakeet toy before. Worked great for me.

I have some onboard 24mm Advantix shots on display <a href="https://home1.gte.net/res0xphr/index.htm">HERE</a>. Man, I really need to update that site.
 

JMTravis

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Go check out a Hobby Lobby or Michaels. I know for a fact that Hobby Lobby carries a nice assorment of diffrent shapes and sizes. I recently bought some there. I would think that Michaels would aslo carry some...
 

Hospital_Rocket

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I'm not sure why you want a first surface mirror. Normally those are used is extremely precise applications. I'm going to go on a limb here and presume a little informatioon is needed

A first surface mirror is one where the reflective media is on the top of the optical flat rather than being beneath a optical substrate. This type of mirror presents the absolute minimum in distortion due to refraction. The downside is that the surface is easily damaged.

If that is what you want here are two suggestions:

1. Edmunds Scientific is where I always got my science fair optics. https://www.edmundoptics.com/onlinecatalog/browse.cfm?categoryid=320&level=2

2. Find a scrap SLR Camera and use the mirror out of it.
 

solrules

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When flying the Apoclypse (7x29mm), we flew with a Aiptek Pocket DV2, reflected using a first surface mirror. I have come to the conclusion that the quality of the camera is much more important than the quality of the mirror. Unless you plan to fly a full fledged videotape recorder or ultra-expensive digital camera/video camera, you can get away with using a regular mirror.

Btw, the first surface mirrors are not too expensive. IIRC, we got 2 for about $8, not too bad considering the cost of the motors or the camera itself. Not sure where we got them, but I can get that info if you need it.
 

Newtons 3rd

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We have found a good alternative to expensive first surface mirrors, that can be found in many auto parts stores. This is the material used to make a temporary mirror for a car or truck. It's inexpensive, easy to cut with shears and is clean enough for all but the most demanding applications. If you find that you need a first surface mirror then I saw some at allelectronics.com. We have used this mirror for dozens of test flights and is what we use in our VPS product.
 

Hospital_Rocket

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Uh oh...

The Cr**P is now really going to fly

Welcome aboard Newton's 3rd!
 

vjp

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Thanks for the ideas & suggestions, folks. I haven't quite found "it" yet, but the automobile mirror substitute sounds like a promising solution, I will check that out today.

As to why I asked about first-surface material, well, it's not so much quality, as it is not having to cut glass and deal with sharp edges (remember the main goal here is a rocket-cam project so easy and cheap, a kid can do it). So a mirrored tape material, or a chromed type plastic sheet would be the ideal choice.

Thanks again for the tips!
 

shockwaveriderz

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instead of using a mirror to look down, I suppose you could orient the camera such that it is looking directly in the direction that you want......

For example, why not use a clear platic body tube to hold the camera and have the camera look out the side or place the camera on a swivel mount such as the rocket tilts the swivel would allow the camera to change the angle it is looking at....

I'm bringing this up as a potential solution because I am basiclaly tired of looking down at the rocket accerelrates from the pad....

I would rather look outwards or daonward at an angle then straight down..
Plus with a clear plastic body tube carrying the camera, on descent..the payload camera could be hung at a specific angle to get really good panoramic pics perhaps?

just my 2 cents....
 

Newtons 3rd

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Another possibility is what we do, and that is orient the camera upside down in relation with the ground during boost. This way the camera is oriented correctly on the chute. The boost phase looks out at the mirror, which is angled so that the edge of the field of view of the camera just encompasses the fin can. This allows a dramatic look down shot during boost, and a nice panaramic shot during recovery. We angle our camera so that is looks down at about a 10 degree angle. Of course this assumes that the payload is located at the top of the stack.
 

Ray Dunakin

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I have LOTS of high quality first-surface mirrors available, and can cut one to suit your needs. Yeah, it's "special order" but it's cheap. Sounds like you won't need a very large one, so I can probably do it for a couple bucks, maybe less. What are the dimensions you need?

BTW, using a regular mirror can cause problems due to refraction and/or double image, as the image is reflected by the glass first, then the silver coating underneath. A first-surface (aka "surface coated") mirror avoids these problems.

Anyone building a camera payload, if you need a mirror just let me know!
 

brianc

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Originally posted by vjp
I'm converting one of those little $20 pencams from Wal-Mart into a "digital cineroc".

--snip--

(I'm trying to keep the project really, really cheap, and really, really easy, so I can post instructions which anyone can follow and make their own with minimal trouble & expense).
Hey! I just picked up one of those pencams the other day. My son and I were
looking at the Estes Camroc and I suggested we look for something digital.

Have you seen this page @ ROL? --
https://www.info-central.org/electronics_dolphincam.shtml

I'm thinking about a hinge flapping type mirror- at launch the cam can shoot
the tail and when hanging under the chute, it would snap the horizion.

Are you planning any mods to the camera itself? Stripping the shell to make it
lighter? Swaping the batteries? What are you going to use for the shutter
control?
 

havoc821

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I have the same pen cam that you got at Wal-Mart. For onboard videos, I use the Dolphin Pen Cam (looks exactly the same) because it is easier to use than the Wal-Mart camera. I found that the camera fits great inside the Estes BT-55 tubing. I would recommend going out and getting a CC Express kit, cut the tube into a 6” tube and a 12” tube. Take the 6” tube and make a tube coupler or buy one for the Bt55 tubes. I found that if you wrap tape around a film canister, it works great as a tube coupler. Cut a square hole in the 6” tube so that the camera lens can “see” out. On the opposite side of the tube, cut another small square hole so that you can use a scrap balsa piece or something to turn on the camera/ set it to video mode. Once you have the holes properly cut and in the right position, you will need to make a mirror on the side if you want video looking at the ground. I went to Hobby Lobby and bought a 5 pack of ¾” mirrors for $1. I used 1/8” balsa to make the frame. Take the mirror and glue it to a piece of balsa wood so that you have 1/8” on only two sides (opposite from each other). Next, cut out two triangles that have that have a base of ¾” and a leg as ¾”. I have found that a 45 degree angle works good for getting the rocket and the ground in the video. Glue the hypotenuse of one triangle to the edge of the piece that has the mirror on it. Do the same for the other triangle. Glue this whole assembly to the side of the rocket over the hole that you cut out for the lens to “see” out. When you glue it on, try to make sure it is aligned with the hole and if you look at the mirror from the bottom of the rocket up, try to make sure that you can see the hole that you cut out and that it is centered in the mirror. Now that all of this is done, you just have to come up with a way to hold down the button so it can take video. To do this, take one of those Estes launch keys that has the black top on it. Drill a hole in the base of the nosecone and put the metal piece in first so that only the black top of the key is sticking out. You may have to build up or sand the black top depending on how close or far down the camera is. When the rocket is put on the pad (you would need a second person to launch it for you) you would hook up the igniters and check to make sure there is continuity. After that, turn on the camera. While doing that, tell the person to put the key in the controller and arm it. Set the camera to video mode, put the nosecone on and secure it with a plastic rivet or something so that the nosecone stays secure while holding down the button on the camera. When you hear the camera taking video, run away and yell out launch. The other person will press the button and off the rocket goes. If I remember correctly, the camera only takes 8sec of video so you probably won’t get any video after ejection because of 2 reasons:

1) video won’t last that long
2) I’ve noticed with my rocket that when the ejection charge goes off, it moves the nosecone a little and causes it to let go of the button. This could also be because I put a screw eye in the tip of the nosecone and attached a shock cord there and attached the parachute to that. The shock cord that leads from the booster is attached to the base of the camera bay. It is set up like this so that if you have a mirror on the side of the rocket, you can still get video of the ground even after ejection because the rocket is still held in a vertical position. It may have let go of the button because the plastic rivet doesn’t always keep the nosecone from moving and when the parachute inflates it pulls on the nosecone a little causing it to let go.

One day I flew one of my video camera rockets on a C6-7 motor and that delay turned out to be longer than I thought. The 5 sec put it right at or barely after apogee, so I thought that 7 would be OK. WRONG! The rocket impacted the ground about 1 sec before ejection. The camera was nearly destroyed. One your camera and my Dolphin camera, the plastic button on top is just a plastic piece that gets pushed down on top of a button that is soldered to the circuit board. Well, on impact (nosecone first) the launch key that I used to hold down the button shattered the top of the camera and ripped the button of the circuit board! I had a friend solder me a switch back on instead and it makes video a lot easier because instead of having to have something hold down the button, you can just flip the switch and that is all there is to it and you can even get video after the ejection charge because this way you don’t have to worry about the button getting let go of. I would recommend that if you don’t mind having your camera opened up, have you or a friend that has god electrical and soldering skills to solder you a switch in place of the button. The only modification to your rocket if you use a switch is that you will need one more hole cut in the rocket so that you can turn the switch on or off. Well, I hope this helps. I will include a picture of one of my camera rockets and a close up of the mirror so you can get an idea of how it is made and set up. BTW, if you build the rocket like I described way above by modding the CC Express, use only C motors and a 3 sec delay. 5 sec will work but I don’t recommend this if you get nervous easy because ejection is after apogee a good bit. Well, good luck and hope to hear how you progress is.

P.S. windex the mirror before you launch it. It really makes the video more clear and launching around noon to mid day will have the best video results!
 
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