switchesvelocity
I'm not at all electronically minded, but am looking for a small electronic circuit switch that is operated by velocity. Many years ago, I used to have a Casio watch that had some sort of switch for the light, where if you turned your wrist 90 degrees at a reasonable speed, the light would come on for 10-15 seconds.
I am now looking for some sort of component that would do the same job, and don't have a clue where to start.
Any help would be greatly appreciated.
Thanks.
For waterproofness you can't beat.
Magnet + reed switch
Magnet + Hall sensor.
Reed switch has advantage of zero off power and no lower voltage limit.
Hall sensor can be more robust.
Reed can be extremely robust if mounted well (floating in soft packing)
These BU520xx hall sensors from ROHM cost about $1.20/1 from Digikey BUT have under 10 uA off state current drain worst case.
2.4 - 3.3 V operation.
If current does not matter you can get 6 MA when off parts for about 1/2 that cost.
If you want single cell operation at 55 uA typical for a horrendous $9.72/1 you can have this marvel.
NVL AFE series. Operation down to 0.9V.
Left goes to mains, middle to your appliance, right goes to ground (maybe via a resistor??). The difference between 5503 and 5508 is that 5503 disconnects both sides of the lamp when off, while 5508 keeps the ground side connected. So the '(un)switched neutral' refers to the neutral of the lamp only.
I don't see the purpose of the 'disconnect the lamp's neutral': the other side of the lamp is still connected to the neutral via the load, so for safety purposes it is still connected.
Best Answer
Making something opereated by velocity is difficult because it needs to measure the relative velocity of surrounding objects or whatever you consider your reference frame. For example, a GPS can do this because it determines its position relative to the earth periodically and can therefore calculate velocity.
It is much easier to measure accelleration, because that can be done from inside a inertial reference frame. Note however that the force of gravity then can't be distinguished from accelleration due to change in velocity.
There small electronic chips that can measure accelleration and report it either via a voltage or digitally. This, with some firmware, can be used to detect specific gestures like you describe. Just like there are small electronic accellerometers, there are also small electronic gyrsoscopes. These report the angular velocity instead of angular position like mechanical gyroscopes do. These small gryros and accellorometers together are used in various motion and gesture detection schemes, like the wii toy, for example.
There are also very basic motion sensors. These look like a switch electrically that randomly opens and closes as a result of motion, and freezes state when stationary. They detect motion only, and are not useful for detecting specific gestures or determining velocity.