a lot of (vague) questions by a noob

[elektromeier]

For an exhibition a fair i was asked by a client to realise a show involving robotic ceiling lights.

The idea is to have around 12 lamps (=robots) hanging on the ceiling. whenever a person enters the room one of the lightrobots pick a person turns on the light and follow it

whereever the person walks.
I know how to do track the persons, coordinate the robots (including track the robots position via an encoded optical pattern on the ceiling). but honestly i have no clue

about motors/batteries/mechanics etc. im a bloody noob.

My idea is to build 2WD robots inside i a cubic case of around 25x25x25cm. in the the four corners of the cube strong neodyme magnets pulling the robot against the metallic

ceiling. the magnets wont touch the ceiling, theres a small airgap between magnets and metal plate so there should be no friction.

the robots will be around 7-11kg each and should move with a speed of around 1m/s. they should also be quite agile and able stop relatively fast. the wheels will have a

diameter of around 20cm. the robots suposed to run around 8h a day but are not permanently moving (depends on the amount of visitors) so i also thinking to park them in

charging docks when theyre not in use or low on battery. the total size of the ceiling is 6x6meters.

the plan is two build a prototype before and make tests with it before i build the rest of the robots… im not sure which motors and which controller i should start with.
i was thinking ordering these components for the prototype:

2 x http://www.superdroidrobots.com/shop/item.aspx/ig32p-24vdc-265-rpm-gear-motor-with-encoder/998/
1 x http://www.superdroidrobots.com/shop/item.aspx/sabertooth-dual-12a-motor-driver/1155/
1 x http://www.superdroidrobots.com/shop/item.aspx/kangaroo-x2-motion-controller/1514/

-anything missing in this list besides the battery, cabling and wheels?

-you think the 2wd design is a good choice for this idea in general? i want to keep things as simple as possible.

-Im not sure if these are the right motors from the gear rate point of view.

-Im also not sure if these motors are under or oversized?

-also does it make a difference if i choose 12v or 24v motors? which voltage makes more sense for my application.

-Do you sell any Circuitry to recharge batteries whithout disconnecting from the motordriver? so the robots could just drive to their charging station when they low on

battery?

-are there suitable motors for this task in angled design AND with built in encoders?

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[SuperDroid]

Sounds like an interesting project. See answers to questions below:

anything missing in this list besides the battery, cabling and wheels?

The main thing missing is the chassis which I’m assuming you will design?

you think the 2wd design is a good choice for this idea in general?

2WD seems like it would be the way to go. If you’re designing your chassis you’d probably want the wheels in the center so the chassis can pivot around the center.

Im not sure if these are the right motors from the gear rate point of view

Use our speed calculator:
http://www.superdroidrobots.com/shop/custom.aspx/how-to-build-a-robot/70/#motors

With those motors and 20cm wheels (direct drive) you’re looking at 2.8 m/s.

Im also not sure if these motors are under or oversized?

Depends on how much force the magnet pulls up with. I’d think IG32s would be fine though.

also does it make a difference if i choose 12v or 24v motors? which voltage makes more sense for my application.

I’d go with the 24V IG32p. They’re better/more powerful for not much more.

Do you sell any Circuitry to recharge batteries whithout disconnecting from the motordriver? so the robots could just drive to their charging station when they low on

We’ve made docking stations for custom projects but we don’t sell any on our website.

are there suitable motors for this task in angled design AND with built in encoders?

None of our right angle gear motors have encoders. You could make something that fits on the tailshaft of the motor.

Let us know if you have any more questions. If you’d like any help with your project, you can also submit a custom request form.

http://www.superdroidrobots.com/shop/custom.aspx/custom-robot-request/87/

Thanks

[Author]

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