Since my sleeping is very deeply, I can't wake up with alarm clock, I thought for a simple PIC-microcontroller project to wake me up. I will suspend a "bucket" full of water from the ceiling above my bed, and at a certain specific time, the PIC will move a motor that causes the water to fall on me :D :D.

But that is not a joke!!
Actually I can write some simple programs with mikroC for dimming a LED, making sound frequences, switches, transistors and relays, for example.

I have searched the web, found many motor types: DC, AC, servo and stepper, but have no idea about the suitable one for my project (it should be able to load a fully bucket). I want also to know how to run it.

Any help would be appropriated

EDIT: I want the water to fall by degrees, hence the motor, not toppling it directly.

  • \$\begingroup\$ Between us, this is more of a robotics question, and we don't do that anymore. Just electrons, you know, with the purple polka dots on them. So the question is likely to be closed. I hear they're working on a robotics site. \$\endgroup\$
    – stevenvh
    Jul 20 '11 at 8:06
  • \$\begingroup\$ What is a bail of water? Straw and hay comes in bails - water comes in buckets, jars, etc. \$\endgroup\$
    – Majenko
    Jul 20 '11 at 8:32
  • \$\begingroup\$ @Matt You likely have experience of farming :) thanks! \$\endgroup\$ Jul 20 '11 at 8:42
  • 2
    \$\begingroup\$ Why not weave a grid of fine wires into your bottom sheet - that way you can shock yourself into wakefulness. It's hard to sleep when you're being mildly electrocuted. \$\endgroup\$
    – Majenko
    Jul 20 '11 at 9:01
  • \$\begingroup\$ @Matt this level may come after the water has dropped, the bed become more conductance so that electrocution is better \$\endgroup\$ Jul 20 '11 at 9:07

Your main problem is to have a stock of dry pillows.

A motor for this is overkill. You don't want to actively rotate the bucket, leave that to gravity. Better to balance it against some rest, so that removing the rest will topple it. You can use a solenoid for this, or maybe a servo (but then we're using a motor again).

enter image description here

To solve the humidity problem: don't fill the bucket with water, but when you balance it, don't tie it, so that it comes down itself. No dry pillow stock needed. :-)

Since you want a slow release of the water you'll need a motor to control the rotation. Use a DC motor with a reduction gearbox. You'll find those on any robotics website.

enter image description here

Another solution, which is mechanically simpler is to use a electric water valve; the bucket can then remain in place. You can find such a valve in an old dishwasher or washing machine. The water valve will probably release too much water, but you can reduce this to drop level by closing the outlet, just leaving a small opening, so that there will only be a few drops released.

  • \$\begingroup\$ Ok, so the suitable motor is the servo? \$\endgroup\$ Jul 20 '11 at 7:01
  • \$\begingroup\$ Or the solenoid. When it's activated it pulls the shaft in, so that the bail's rest is removed and it topples over. With a servo you could do the same thing, but then the movement is rotational instead of linear. Servos will be easier to find. \$\endgroup\$
    – stevenvh
    Jul 20 '11 at 7:05
  • \$\begingroup\$ There are also solenoids which pull out when activated, so be sure to pick the right model, otherwise you'll have to have it activated all the time. \$\endgroup\$
    – stevenvh
    Jul 20 '11 at 7:16
  • \$\begingroup\$ Btw you can get some pretty tough solenoids from pinball machine parts stores. \$\endgroup\$
    – drxzcl
    Jul 20 '11 at 7:19
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    \$\begingroup\$ The PIC can't drive the solenoid directly; it requires to much current. You'll need a transistor. Here on EE you'll find examples how to drive a relay from a microcontroller, it's the same schematic. "fall by degrees", you mean have complete control over the released amount of water? No, the solenoid will pull back or not, it's an on/off device. I edited my answer. \$\endgroup\$
    – stevenvh
    Jul 20 '11 at 7:31

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