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Topic: Pan Tilt camera platform (Read 2419 times) previous topic - next topic

stormadvisor

Howdy all,
I had a project idea I thought I'd look at doing.  I've searched the board and did not see anything regarding this.

First off, the idea I have is probably way over my head since I have no experience with the Arduino.

What I want to do is make a video camera mount that will pan and tilt.  It could be used with handheld or security type cameras.  I would like to have a joystick control for it and maybe go so far as a button to start and stop a set process of panning back and forth.

It should only pan 350 degrees +/- at most due to cables.  I figured on using servos for both the pan and tilt functions.

This setup will be used for an Amateur Radio TV camera in disaster settings.

Thanks

AWOL

#1
Aug 25, 2009, 04:01 pm Last Edit: Aug 25, 2009, 04:02 pm by AWOL Reason: 1
If you look at some of the amateur robotics sites, you may find simple mechanisms for standard R/C servos to attach a very lightweight chip type CCTV camera.
Handheld cameras are heavier and may need bulkier servos.

However, it's all fairly simple - just have a look around the Playground.

350 degrees may be a problem though - most common servos do 180 degrees or less.

A two axis, joystick-driven servo mount is probably about 30 lines of code. Adding auto-pan and amanual/auto mode switching maybe another 10-15 lines.

Start simple with a single pot and a single servo.

Have fun!
"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

Cabe

http://www.acroname.com/robotics/info/ideas/continuous/continuous.html

Should solve the limits from the servo :)

AWOL

@Cabe, but then we call them motors, not servos.   ;)
"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

Cabe

I'll give you that, but at least "servomotors" give you an easy control method.

Ran Talbott

Forget servos:  they're just not strong enough for anything beyond the lightest of point-n-shoot still cameras.

I've seen some low-end units from China on ebay for about $100-150 that claim to be strong enough to handle a few pounds of camera.  They probably wouldn't stand up to heavy use for very long,  but would probably do for tinkering.

You might also check with any security/alarm dealers in your area,  and ask if they've got anything used from systems that have been retired or upgraded.  If they've made their profit on them,  they might be willing them at scrap-like prices.

Ran

drone

Quote
Forget servos:  they're just not strong enough for anything beyond the lightest of point-n-shoot still cameras.


That's a fairly odd statement, since servos are used in everything from BIG high-end CNC machines to, more saliently, camera control rigs.  

There are all kinds of servos, not just those little hobby ones, but even a little hobby one can be brought to brunt with proper gearing.  Notice a trick that servocity does with some of their pan and tilt mounts when using servos - they use the final drive shaft to run the servo potentiometer, allowing your control over _the final shaft motion degree_ rather than the motor shaft motion degree.  

I wrote about how to make your own servo using a DC motor a pot some time back, but you can easily attach your hobby servo to a geared-down final drive shaft.

I wouldn't discard servos because they're not powerful enough, but because they may not fit your application.

If you want to program it to move to certain positions, programmatically, you can achieve this fairly easily with servos.

If you only intend to do fly-by-wire, DC gear motors will generally be easier to deal with - there's no benefit of a servo in this case, except error correction (i.e. not moving as far as you intended to move).  In fact, servos complicate the model a little.

Additionally, you could also do programmed positions by doing your own feedback loop (read: encoders) from DC gear motors.

You say security cameras, I presume you mean little tiny ones?  What's the weight you're looking to move here?

Here're a couple of examples from servocity, the first being a full gimble-type setup to move a large camera, and the second, a smaller unit for moving tiny cameras.  Their medium-duty units let you drive full-size dSLRs (I know, I've got one of their medium-sized units at home).  They should help to give you some ideas on how to build one.

http://servocity.com/html/pt-2100_pan___tilt_system.html

http://servocity.com/html/spt200_pan___tilt_system.html

Let's not forget though, the great and powerful stepper motors =)

!c

Ran Talbott

It's only "odd" because I didn't explicitly state my assumption that,  like at least 95% of the people using the term here,  stormadvisor was referring to RC hobby "servos".

That little pan/tilt from servocity is very cute,  but there's no way it'll handle the standard "security camera" that stormadvisor specified in the original posting.  Especially since it would have to be weatherproofed to be used as "an Amateur Radio TV camera in disaster settings".

Ran

stormadvisor

Quote
Let's not forget though, the great and powerful stepper motors

I had thought about that.  I do not need quick action as much as just being able to move the camera.  

The size of the camera will be determined by what we can get ahold of.  

Thanks for your suggestions.

lordzeppo

#9
Sep 01, 2009, 06:02 am Last Edit: Sep 01, 2009, 06:02 am by lordzeppo Reason: 1
I can answer that problem I think.

I'm currently working on the exact same thing as you storm but for a bigger camera,Cinema sized (40 pounds) thing ^^

We have basicly 2 options

A:Find some decent continuous servo tha tcould handle the stress or

B:Use DC motor geared down with a pot geared up linked with the "table" of the camera,this way you could go like 380 degrees(making sure u cover it all) and the pot geared up gives you control on the position.

I have a proof of concept thing i did just about 5 hours ago ^^ and I'll post it around here soon enough,I linked a standard pot 2 axis joystick to 2 servo for panning and tiliting and so far,my tiny 9g servo would easily move a webcam without problem (they are rated 1kg/inch) which is pretty awesome for 9g worth of plastic ^^

If people are interested in that pan tilt head I made,jsut ask and I'll make a video(youtube) and post it (skyblog) around here.
Also,the coede I made to go with it work y incrementing the servo value instead of being the actual position of the joystick,this way,u can leave it where u want it to be,and if you wanna add a auto pan trought the scene function,press a button that trigger a loop that set the x increment as +1 and every 0.1 second the servo will move by 1 degree  untill you hit the desired point.

Same with precise locations,you just make a part of code to send you back the position of each servo,and you write them down,then implement a function setting servo on this particular value.

I hope this helpd,if u need more,just ask.

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