motor to pull camera dolly

[apostolakisl]

Here is a crude sketch.

After thinking about it, it would be easier to just press the small electric motor's spindle against the rubber wheel. A small spindle against a large wheel will gear it way down. If you use a rear bike tire of a 10/12/18 speek bike you will have the chain sprockets available. You can use a long bike chain (bike chains can be hooked together, one of the links is removable) and run it to another bike chain sprocket (another rear wheel would work).

Speed can be adjusted by picking one of the different sprockets or using more or less voltage on the little dc motor.

If you have two bikes sitting around, all you need is the long chain and the motor. If you have enough space, you don't even need to take the wheels off the bike, just put the two bikes back to back however far apart you need, lift the rear wheel off the ground (or turn bike upside down), and run the chain between the two rear bike sprockets. You will need to build a mounting device for the small electric motor holding it pressed to the tire.

This would be very "Wright Brothers"





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As far as getting the camera to take a picture every x seconds, does your camera have an ir remote? Mine came with one. Anyway, crack it open and solder two leads across the microswitch and hook that to a relay.

 

[electron]

With a high end DSLR, you need an external intervalometer. If you have a cheaper consumer grade Canon camera, you can use the awesome CHDK firmware (I use this with cheap Canon PowerShots to create portable 'sentinels') to do all of this.

Have you modified your camera for astrophotography? What parameters did you use? This is something I am actively getting into myself, but don't have the guts to modifiy my camera.

 

[v1rtu0s1ty]

Here is a crude sketch.

After thinking about it, it would be easier to just press the small electric motor's spindle against the rubber wheel. A small spindle against a large wheel will gear it way down. If you use a rear bike tire of a 10/12/18 speek bike you will have the chain sprockets available. You can use a long bike chain (bike chains can be hooked together, one of the links is removable) and run it to another bike chain sprocket (another rear wheel would work).

Speed can be adjusted by picking one of the different sprockets or using more or less voltage on the little dc motor.

If you have two bikes sitting around, all you need is the long chain and the motor. If you have enough space, you don't even need to take the wheels off the bike, just put the two bikes back to back however far apart you need, lift the rear wheel off the ground (or turn bike upside down), and run the chain between the two rear bike sprockets. You will need to build a mounting device for the small electric motor holding it pressed to the tire.

This would be very "Wright Brothers"





Uploaded with ImageShack.us

As far as getting the camera to take a picture every x seconds, does your camera have an ir remote? Mine came with one. Anyway, crack it open and solder two leads across the microswitch and hook that to a relay.

I got it now. Problem is that it's bulky. I'll try to think of another way which uses your concept. I really appreciate it.

Thanks so much!

 

[v1rtu0s1ty]

With a high end DSLR, you need an external intervalometer. If you have a cheaper consumer grade Canon camera, you can use the awesome CHDK firmware (I use this with cheap Canon PowerShots to create portable 'sentinels') to do all of this.

Have you modified your camera for astrophotography? What parameters did you use? This is something I am actively getting into myself, but don't have the guts to modifiy my camera.

Yes, I have a simple Canon camera which I can try. I'll check that link later.

I didn't modify my dslr camera for astrophotography. I used f4, 25 secs, iso 800-1600. I've seen people use iso3200 to capture more stars.
I just used an intervalometer. 25 secs for the shutter and 1 second for the next shot and so on. That video I made took 2-2.5 hours. I started at 1:30am. I set my android to alarm at 3:45am so I can sleep. LOL. Glad my camera was still fine and not hot. hehehe

I noticed though, I have now 4 dead pixels(show as red on picture). It's seen on my video.

 

[v1rtu0s1ty]

My Powershot SX120IS is not listed. bummer

 

[apostolakisl]

I got it now. Problem is that it's bulky. I'll try to think of another way which uses your concept. I really appreciate it.

Thanks so much!

If this is a setup you plan on keeping for a while and using it multiple times, then it would be worth your time to make it a dedicated setup (not intact bikes). Any electric motor you get is going to be high rpm, low torque. You want the opposite, low rpm and high torque for smooth continuous motion. So the deal is to gear it down which will give you high torque/low rpm. Bicycle gears are readily available, inexpensive, and can be bought with the bearings already in place and ready to be mounted. So, skip taking the full out bike parts and just use the necessary parts.

 

[v1rtu0s1ty]

Most likeky Lou, I cannot use this motor that my son gave to me today. Right?

So the things I need are, correct it please if I'm wrong
1. low rpm, high torque motor
2. by bicyle gears you mean sprockets

 

[apostolakisl]

Here is another concept. This is quite finished yet, but it is functional. It is an automatic door opener/closer for my chicken coup. The mechanicals are finished, it is just hooking it into the relays so I can control from my Elk m1 that isn't done.

I built this entirely out of stuff I found in my garage. The motor is from a car power window that i have had sitting around for 15 years (I knew I would need it someday, my wife just doesn't understand why I keep this stuff, so I had to point this one out). Anyway, it is a metal pole that I slid a vinyl tube over. I welded up a bracket for it and used a lever with a rolor on it to press the pole against the power window gear. I had to buy that spring, it was the only part I didn't have sitting in the garage.

This concept would work for you as well, but again you would need to gear the motor way down. Obviously this moves way to fast for you.

 

[v1rtu0s1ty]

That is so cool! What is that motor? Can it infinitely loop and only stops whenever you tell it to? I think that will work for me.

Here is what I was thinking when it's controlled by my M1. I would turn on the relay for 1 second which would move that motor really short. Next, ELK sends another command. It takes the picture by telling the relay connected to my intervalometer to turn on for 25 seconds. When it's done with the shot, ELK would go back to step 1 which is turning on the relay again connected to that same motor on your video. That should work right? If you will estimate, how many millimeters will it move if you turn it on for 1 second?

 

[apostolakisl]

Most likeky Lou, I cannot use this motor that my son gave to me today. Right?

So the things I need are, correct it please if I'm wrong
1. low rpm, high torque motor
2. by bicyle gears you mean sprockets

That motor might work. I am sure it spins like crazy, but is easy to just grab with your fingers and stop. You need to use a gearing mechanism to convert that high rpm, easy to stop spinning, into a slow spinning, hard to stop wheel. I also assume your trolly will move as effortlessly as the one in the video.

Whether that motor works or not depends on just how powerful it is (probably powerful enough) and what kind of tools you have to fabricate your contraption. That spindle shaft comming out of it is short and slippery. I am thinking a bike wheel with the tire removed and the rim covered with traction tape (the kind that is a little foam like, not the gritty kind). They sell this for sail boats. You push the motor spindle against the edge of the traction tape covered rim, and the spinning motor turns the whole bike wheel. This would be the only bulky part of your contracption. It is necessary to use a large wheel unless you want to have multiple smaller gears. Multiple small gears is only for people with full out machine shops.

So, you need a mount for the little electric motor and a mount for your larger wheel. The motor mount has to be on a hinge so you can put a spring on it like my chicken coup thing pushing it tight to the wheel. You will need to experiment with different springs. The one that worked for me was my third try.

And yes, I mean the sprocket sets on a bike.

 

[apostolakisl]

That is so cool! What is that motor? Can it infinitely loop and only stops whenever you tell it to? I think that will work for me.

Here is what I was thinking when it's controlled by my M1. I would turn on the relay for 1 second which would move that motor really short. Next, ELK sends another command. It takes the picture by telling the relay connected to my intervalometer to turn on for 25 seconds. When it's done with the shot, ELK would go back to step 1 which is turning on the relay again connected to that same motor on your video. That should work right? If you will estimate, how many millimeters will it move if you turn it on for 1 second?

I don't think turning it on for 1 second will give you a consistent number of millimeters moved. I don't know what your plus/minus is for this device, but I bet your range would be really big doing it that way. That is why I think a continuously running motor that is geared way down.

And that motor is from a car power window. It has a built in gear which already slowed it way down and torqued it up, but you need much slower yet (torque wouldn't be an issue using that motor, it has plenty even at higher speed) And, yes, it can keep running until it runs out of pole and reversing the dc power source polarity puts the motor in reverse. And it starts and stops by just killing the power. But there is a ramp-up and and ramp-down every time you hit the juice.

If you can find a power window motor like that one, you might try hitting it 2 or 3 volts and see if that slows it down enough for you. I have it on 12v in the video and did test it at 6v. At 6v, it moves about half as fast. At some point, dropping the voltage will just not turn the motor at all.

 

[v1rtu0s1ty]

Yes, the motor works. I used a AAA 1.5v battery. I gripped the spindle shaft and I think it's strong enough since it didn't stop immediately. However, it rotates fast.

 

[v1rtu0s1ty]

like this?

http://www.scientificsonline.com/high-torque-dc-electric-motor.html

 

[apostolakisl]

Totally different idea.

Connect your trolly to a string that wraps around a winch. Spring load your trolly to pull against the winch. Use a solonoid to release the winch one click at a time. The solonoid could be powered by an Elk output.

 

[v1rtu0s1ty]

like this?

Spring load your trolly to pull against the winch.

I'm confused about this part.

You also mentioned solenoid. Is it the same as the solenoid in sprinkler valves? If so, I have those. Hopefully I can ask another favor. Can you draw a diagram for this new setup. I'm slow and not good at understanding words.