Mark-World - Tech Projects To Amuse The Curious
Presenting 'The Better Mouse Trap'

It has been said that a classic challange for a multi-diciplined engineer such as myself is to 'Build A Better Mouse Trap'.  Naturally I had to give it a try once I had a real need for such a device.    So here I present my version of  'The Better Mouse Trap'  (IMHO)

The goals of this mouse trap of course included that it must be able to trap mice.  That was done 3 times with this trap and it works quite well.  The trap does not harm the mouse.   Another goal of this trap was to try to make it low power so it could sit for days with very minimal battery usage prior to trapping the mouse.   The mouse trap runs on two AA batteries and can sit for a very very long time then trigger and catch the mouse.     
The 'Better Mouse Trap' uses the grey trap mechanism found in stores for catching mice as the mouse chamber.  Near the right end of the mouse chamber  but not all the way in we put an IR diode and on the other side a detector.   Just past this light 'trigger' we place some food for our hungry mouse.     The door of the trap has a rubber band that wants to close the door but the solinoid seen in red just below the mouse window does not activate till the mouse triggers the IR diode light path.    The door has a latch to mechanically hold it closed.

For mouse #1 I had no 'window' and soon realized a window was a very valuable and fun addition so here we see mouse #2 huddled in the back trying to hide.  The circuit was designed for minimal components and lowest standby power as I could tolerate.  

The circut is powered by two AA cell batteries in the battery compartment to the upper left.   The upper right shows the on/off switch and the 'reset' button used to place the trap in 'waiting to trigger mode.  A key goal besides long battery life for this mouse trap was more on the technical challange end of things as I decided that I would make a single IC called a 'quad OpAmp' do everything and that was quite a trick that was rewarding to pull off.  The black case by the way is taken from a different kind of electrical mouse trap that electricuted a mouse but that is all taken out and I only used the nice switch and battery holder and the rest of the case to hold my other parts of 'The Better Mouse Trap'.   

Mouse #2 In The Trap!

I hope you found this project as fun to read about as I found it to design and put into practical use.
Presenting:  The Better Mouse Trap
Mouse Trap