Help understanding motors & functions

[teos]

I have an idea for my battle bot, though I'm new to power functions and how motors can achieve them.  Is it possible for one motor to control more than one function via the remote/receiver?  If so, does anyone know of a set where I could see an example of how this is achieved?  I have limited space within my bot and it would be better if I could do everything else with only one more more.  Thanks!

Building tips and advice are always welcome.

[aminnich]

You would need a gearbox to accomplish what you want.  One motor and as many functions as you want.  But, you would need another motor to change the gear since the contest is all remote control.  

Hope that helps.

[krtwood]

8043 is the only official set I can think of that uses remote control to switch functions.  The gearbox takes up more space than the motors do so if space is the problem you are probably better off just using motors directly.

[Nazgarot]

I have made a mechanical sequencer that will allow you to use one motor to control two functions in sequence. It can be reversed at any time, and will revers the functions from wherever they are in the sequence. The motor will reverse the sequence from whatever point you reverse the motor. The only challenge is that the mechanism has a fair bit of resistance, taking a good part of the motors power. The thread has suggestions for other more compact designs as well.

If you only need the motor to work in one direction on each function there are simple "gravity" latches that will allow the motor to switch between functions by changing directions.

If you need a larger total amount of functions than motors, say 7 functions from 3 motors, it is possible using gearboxes and smart combinations of functions, but it requires both space and probably a redesign of all functions to incorporate. Example: A car with one motor for forward reverse, one servo for steering, and two motors for additional functions. By combining steering with a function selector it can have 4 or up to 6 extra functions utilizing the 2 extra motors and adding two extra functions to the forward reverse motor. (This is easier to explay if I draw it, but I don't have time at the moment. If you find it hard to understand I can make a drawing tomorrow). Say we use an example with steering and 4 extra functions on two motors. The forward reverse motor is only used for those functions (recommended if you don't want the model to roll away as the functions are activated, but can be used for functions combined with driving forward/reverse). While steering left the servo is also activating two gear selectors, activating function A (motor 1) and function C (motor 2). Those motors can be used for function A and C as long as the servo is still turned left. The moment the servo is released function A and C is disabled as the selectors are put back to center. When the servo goes right the selector activates function B (motor 1) and D (motor 2). These functions can now be used as long as the servo is kept right... 

Now, you can use any combination of these solutions to make even more advanced function selectors, but beware of the following:

1. The more selectors you use, the more play the functions get.

2. if you don't use worm gears to lock functions they will not lock when a selector is deselected (center position)

3. If you combine to many functions you are going to run into torque problems.

4. Keep you gearboxes simple and make as few gears of the opposite function (other position of selector) as possible turn when deselected or => Torque problems...

5. The mechanical sequencer takes a lot of torque to operate. To use it for powerful functions like lifting stuff with linear actuators I recommend using a XL motor.

6. Remember, all gearboxes and function selectors are going to need more space than extra motors... A selector roughly requires the same space as a M motor, though it can be easier to integrate.

7. I've always wanted to try using a micro motor for a selector function, but I never can seem to make it work due to it's very low torque. Though if you can make it work it would be a very good solution for a compact selector.

 

Good luck, and don't be shy to present you model here. We might have suggestion on how to improve it...

-ED-

 

Edited March 20, 2017 by Nazgarot

[aeh5040]

It is possible to control 2 functions with 1 motor.  It is possible for the two directions of motor rotation to power different functions. The only official set I know of that does this is 4895.

[allanp]

A model in the control center 1 set also changes function by changing the motors direction.

[Blakbird]

11 hours ago, allanp said:

A model in the control center 1 set also changes function by changing the motors direction.

Yep, that would be the crane, 8094_4.

http://www.technicopedia.com/8094.html#4