Turning Stepper Motor Off

@will The challenge with them is coming up with a way to connect to the camera. The advantage of the AC adaptor is it already fits in the battery compartment trailing a 110VAC line. But the soft sided LiIon may be the best choice to power the small inverter.

@zander 

You've stumped me again 🙂 Why would you need an inverter, does your rig run from a wall plug ?

I think you could ameliorate the holding power problem (for both steppers and servos) somewhat. While the platform is rotating, you'll need all the torque you can get, but once it's in place the holding requirement should be a lot less.

I think the steppers draw more power when holding because the current flow is NOT being chopped up as it is when the coils pulse on and off, it's continuous to hold the magnets in place. I suspect that you could use PWM on the power supply to the motor to reduce the holding power by adjusting the duty cycle. That would help slow battery drain.

@will Oops, you missed the post where I said the double battery pack would push the weight too far over the limit so I need to find some sort of way to hook up power to the camera. On a search I encountered the AC adaptor which I had forgot about. Now the batteries can be external strapped to the tripod and I build a tiny inverter to plug the AC adaptor into. Not the most eficient solution but I can bring more battery to that setop, I already have a 10,000mAh pack and an 8x18650 so I think thats about another 20,000mAh and both combined are about a brick in size.

@will My approach is to turn off the motors during the hours of non movement and invent some sort of electro mechanical brake. That way the power is only needed for the few minutes out of the entore shoot where motion is required. Of course some subject matter may require more movement than others, but the typical nesting bird is the normal scenario, or a burrow or lay up spot.

Posted by: @zander

common sense except for the 400ft rule

Just wait, in the offing there might be ADS-B for drones.  Have not found the root information in the Federal Register yet.  There are seeminglly FAA grumblings. I am surmising that the 400-foot rule came about to give separation between uncontrolled space and the floor of controlled airspace above should there be any.  Perhaps, another reason is the ability to sustainably "see" and keep in sight the drone against the various "sky" backgrounds?

@zander

Posted by: @zander

@will My approach is to turn off the motors during the hours of non movement and invent some sort of electro mechanical brake. That way the power is only needed for the few minutes out of the entore shoot where motion is required. Of course some subject matter may require more movement than others, but the typical nesting bird is the normal scenario, or a burrow or lay up spot.

It might pay to look into some of the very small worm gearboxes, or if you can't find one, make one that mimics the behavior out of low lead leadscrew from the 3D printing world, with the spring loaded backlash nuts - perhaps with a heavier spring etc... a bit of experimentation can go a long way.

@frogandtoad That sounds reasonable, but I am genetically unable to operate a CAD program. I can read machine code but CAd is a mystery to me. I am giving up, I don't see a workable cost effective solution.

Posted by: @zander

I am giving up, I don't see a workable cost effective solution.

I'm curious about you think is a cost effective solution given that the "deluxe" solutions run from $5000 up ?

Aside from the value of your time, what do you feel would be a reasonable amount to pay for the parts to implement a basic azimuth/elevation mount strong enough to manage a 3kg camera plus lens(es) that doesn't have to follow movement of the target.

@will Somewhere I lost you. My exiting motorized DSLR camera mount is more like $500, max wt is 6lbs. My cost limit for DIY is more like $100 max $200.

@zander 

OK, the $5000 deluxe I was talking about was for the telescopic mount you mentioned earlier. I used it because it represented the most exotic, expensive mount discussed.

$100-$200 is the range I was looking for, thanks. I'm going to add this to my projects list to see if I can come up with a reasonable design within that budget.

That said, it's probable that you'll never hear me mention it again 🙂

PS, is it reasonable to assume that your friend already has a good tripod with a camera mounting screw on it ? I'd like to start knowing that the design only needs to proceed from the camera and motion control system up. In other words, I'm cheap so I don't want to need to figure the cost of the tripod into the total value of the project 🙂

@will Somewhere along the line I confused you and probably everyone else. Someone guessed it was a telescope mount, and yes they start at $2000 for a motorized goto mount not including scope that actually costs less if a mirror, starting price for an APO refractor though (may be more today)

The device I am wanting to build is a terrestrial wifi controlled pan tilt head to go between a normal/heavy duty photography tripod and a 35mm DSLR.

@zander 

I don't feel confused, like I said I was just looking for a range and you specified it. So, I'm happy 🙂

@will Yes, assume he has a standard tripod and standard 1/4-20 bolt that attaches to the standard camera 1/4-20 hole.

@zander 

Thanks for the extra info. I have no clue about cameras, so that helps me a lot.