It seems so simple

Hello,

I’m really new to all of this and after several hours of searching multiple internet sites, I still can’t find a straight answer to a question I have, so I’m hoping somebody here can give me a simple yes or no.

The Project: My wife wants a “sunrise” alarm clock. The kind that slowly raise the light level over a period of time in the morning. She could simply buy one, but what’s the fun in that? Also, the only one she was able to see in person was unimpressive. I’m fairly certain that I can build one that will be superior in function - even if the aesthetics are somewhat less appealing. She’s willing to live with the trade-off.

The Problem: I have no programming skills whatsoever. None. Nada. Zip. If I did, I assume I’d have understood more of what I was looking at and would probably not be here asking any questions. I’ve ordered a couple beginner books to learn a little more about robotics in general, but I still doubt that I’ll be ready to program anything in the very near future. Fortunately, I think I’ve come up with a way to mechanically overcome my lack of programming ability so I can slowly raise the light level over a set period of time.

The Solution: What I need ( and this is my real question ) is a small motor or servo that will turn at a very low RPM ( or that I can gear down to achieve the same result ). I found those… but what kind of controller do I need? In a nutshell, my design would call for an adapter that is plugged into the wall sending power to ( I assume ) a motor controller that powers the motor. This is where I’m lost because I don’t want something I have to program, I just want the motor to run when the power is on and I haven’t seen anything that says it will perform that specific function. I’m still deciding if I’ll control the intensity of the light by using the motor to manually turn a dimming switch or if I’ll design some type of shade that will slowly open to let more light escape. Either way, all I need is for the motor to run when the current is on and for it to stop when the current is off. I can control the on/off and duration of the current with a simple light timer and hopefully eliminate the need for any programming… Can anyone point me in the direction of the components I need?

Thank you in advance for any help you can provide as it is greatly appreciated!

One approach would be to use a brushed DC motor. You should select a motor that supplies enough torque and turns at the right speed for your application. You can power the motor from a wall outlet through a DC adapter; this will make it run whenever power is supplied. You should select a power supply that supplies a good voltage for your motor (higher voltage means a faster, stronger motor but it will draw more current and might wear out sooner). Also make sure that your power supply can deliver all the current that your motor is going to need.

Here is a link to a comparison page for the motors we offer:
pololu.com/search/compare/34 … ,71,13,8/x

Here are the DC wall adapters we offer:
pololu.com/catalog/product/1607
pololu.com/catalog/product/1640
pololu.com/catalog/product/1641
pololu.com/catalog/product/1642

-David

Hello.

I wrote this earlier, but I guess I forgot to hit submit.

If you just want the motor to turn when power is on, you don’t need anything else: just connect the motor to your power supply. In general, though, this sounds like a very inelegant solution. If you’re going to be covering the light all night, make sure you do it in a way that doesn’t create a fire hazard.

- Jan

First, thank you for the responses I really appreciate it.

As far as wiring it directly to the motor, I assume you mean that I’d need to cut off the connector on the power supply and solder those to the tabs on the motor? Is there a positive and negative terminal on the motor or will wiring it one way make it turn clockwise and switching the wires make it turn counter clockwise?

Also, the light won’t be on all night, the current will be controlled by a standard light timer.

Thanks again for the help!

Yes, you could cut off the power supply connector and solder the two wires to the two terminals of the motor respectively. But if you want to be able to reuse the power supply in the future, you could get our DC Power Adapter Barrel Jack which works with three of the power adapters we sell. Connect the power adapter to the jack, and solder wires from jack to the motor terminals.

Wiring the motor one way will make it turn clockwise. Switching the wires will make it turn counter-clockwise.

-David

Thanks for the help guys, I appreciate it. I’ll let you know how it works out!