Altering a cat toy?

[caphair]

Picked up a cheap small vibrating cat toy. It's just a vibrating motor, batteries, and on/off switch.

Cat loves to swat at it and I was wondering how I could have it turn off when she hits it and on if she hits it again. Would be more entertaining for her.

It's only about 2 inches in length, inches in width. Is there a type of switch I could wire in that reacts to impact?

[momaka]

Re: Altering a cat toy?

I don't think so, but I'm not an expert.
Perhaps some kind of a tilt switch could do the job of "random" twitching - that is, if the cat makes the toy flip a certain way, the toy won't move anymore, but if the cat touches the toy again, it might just activate the tilt switch and make the toy move again. I dunno... But outside of a microcontroller and some sensor, I'm not sure if there's another way to exactly achieve what you want.

[caphair]

Re: Altering a cat toy?

I don't think so, but I'm not an expert.
Perhaps some kind of a tilt switch could do the job of "random" twitching - that is, if the cat makes the toy flip a certain way, the toy won't move anymore, but if the cat touches the toy again, it might just activate the tilt switch and make the toy move again. I dunno... But outside of a microcontroller and some sensor, I'm not sure if there's another way to exactly achieve what you want.

Tilt switch might just be perfect actually. As long as it can keep turning off at random should be better than just constantly on

[eccerr0r]

Re: Altering a cat toy?

and that's what the microcontroller is for, to turning off at random...

Microcontroller could discern shaking of the toy whereas a simple on/off tilt sensor may not. Perhaps a supervisory routine of detecting motion by the tilt switch changing states (either on->off or off->on) would trigger the state machine of whether to turn on vibration or not depending on timeouts.

interesting project, and requires microcontroller. Not sure if it would be feasible to make it small enough any other way.

[petehall347]

Re: Altering a cat toy?

i wouldn't be surprised i china could supply the parts for less than the price of a cup of tea

[AdrianM]

Re: Altering a cat toy?

How's about using a piezo to trigger a mosfet for a short duration - the cat pawing the mouse should make it react for a while then shut off.



The piezo generates a small voltage when hit, rectified by D1 and held on C2. R1 discharges this over 4 or 5 seconds and while above the gate threshold of M1 (around 2V) the mosfet holds the motor on. D2 clamps the gate voltage to a safe level.

Even a fairly small piezo should work OK for this and the best thing to do is add mass to it by sticking a steel nut or lead fishing weight to the ceramic side. The inertia of the moving mass flexes the ceramic generating an alternating voltage pulse. Not much current, but not much is needed to turn-on a mosfet.

However, some current is needed to build up a charge on C2 so without testing it I'm not sure if these values would be best. In principle the mosfet gate alone will provide sufficient charge storage however the total leakage might not be enough to get away without a bleed resistor R1 to get it to switch off after a few seconds. Many 10's of mega-ohms would be required which is why I spec'd C2-R1 values to be more easily controlled.

[AdrianM]

Re: Altering a cat toy?



Well, it does work. I left out R1 and changed C2 to 1nF to get around 1 to 10 seconds on-time depending on how hard it's poked. I'm not sure how the physical side of things would work out inside a toy though. That's with a FQP7N10 mosfet I had laying around on the bench.