Here is a project I want to undergo, but Im a quite a bit confused on how to do it. I have an old laptop that needs to be taken apart to get running (power adapter cable is broken). I was thinking of building a case for it that would mount on the bottom of the shelf right above the desk. The case would be 3 layers. Layer 1 = Components, Layer 2 = Empty Spinning Wheel, Layer 3 = Monitor. Here is what I want to do: With control through a program (future control of a remote, meaning a program that can work with a remote), control the angle that monitor goes down. So basically, in the closed position the monitor would be closed like laptop is closed. When I send a command to the motor, the monitor opens (in the same way a laptop opens), until the degree I want it to stop at (or roughly at that degree) The purpose of the second layer, is so that I can control the way the monitor is pointing. Turn on the motor, and set the angle (for example different angles are needed in different sitting arrangements so I want to be able to control that) Here are my questions: Any good websites to read up on control Servos/Steppers? What kind of stepper would be need to lower and raised a 2lb monitor + frame? Is a stepper or servo that best way to accomplish this? I dont want the laptop running 24/7 so would the stepper or servo lower the monitor (due to the force of gravity) if there is no power in it? Any other comments would be greatly appreciated.
Might I suggest using a lever or pulley with a counterweight so that your motor doesn't have to both pull and lock the load? If you balance it correctly, you should be able to move it up with minimal force, and it'll stay there without the motor staying on or locking somehow.
I think I see where iamnafets was getting at. Take a cable and at each end attach 2 lb masses. Drape the cable over a pulley. The string would be perfectly vertical for both masses and since the masses are identical, they will be in equilibrium (well, assuming the cable's mass is negligent). Now imagine using a servo to adjust the position of one of the masses. Since everythinn was in equilibrium, it will take a minor amount of effort to do and then perhaps a locking mechanism can restrict further motion of the cable/monitor. I can see the benefits of this. Rather than use a very bulky and expensive servo, you can use a relatively cheap one. In fact, you'd be able to use seevral smaller/standard servos to perhaps raise the monitor, and another one to operate a position-locking device. If you want this all programmable, I'd look into getting a microcontroller such as the Basic Stamp II from Parallax (parallax.com). There are cheaper options out there but this is a popular option. As for servos... you can get decent standard servos for as little as $10 a pop. $15 or so will get you one with better bearings. You can also modify them so that instead of using a servo for precise positioning, you can use one to rotate continuously.
Using the pulleys and a cable is a good idea, however it limits the angle. Because there would be nothing pushing it pass 90*
Don't get a Stamp, get a picaxe (very similar but a good picaxe costs £1.50) from www.techsupplies.co.uk, easy and small (single chip)
heres a suggestion, get one of those tracker webcams, and use the servo commands from the servos in the webcam to move the monitor as well, so if you moved at all in the room ( say put your feet up on your desk or something) then the monitor would move with your head, so it would be always at optimum viewing angle.
Right. Well, you may be able to incorporate some type of a counter-balance system simply because otherwise you're going to need to buy a heavy duty (ie expensive) servo. As for microcontrollers... you're going to have to make your own judgements as to whether or not you even need or want one. You can just use circuitry to achieve what you want, but it won't be as easy as incoporating a microcontroller. If you end up googling this, look to see which microcontrollers that robot hobbyists use. There are a lot of popular ones out there. I just looked at the site for the picaxe, and it seems like a novel idea but after spending 15 mins browsing, I have my personal doubts as to how good their product is.
