Hacking the spy gear motion detector from McDonalds Happy Meal.

A friend of mine recently purchased a happy meal at McDonalds.
(40 Yrs old and she eats Happy Meals, go figure.) Included with it was a spy gear motion detector toy. She knew I liked gadgets and brought it to me.  Basically you set it some place stationary, say in a hallway and if anyone walks through the area it will light up and beep. Very cool toy and amazingly enough it works pretty darn well.  

Except for one problem. The beeping sounds like an anemic canary at the bottom of a 100ft mine shaft. I assume the manufacturer intended this so as to not tick off the parents. Imagine driving home from Mcdonalds with a real motion alarm constantly sounding. My ears aren't what they used to be so i decided to see if I could easily make it any louder.

For this Mod you will need the following tools.
  1. Dremel tool or electril drill with a small bit.
  2. Size 1 Triwing security bit for screwdriver.
  3.  small strait bladed screwdriver.
The triwing security bit is a bit hard to come by. I have a set of Wiha security bits I found on the net for less than $20. It might be possible to loosen the security screws from the device with a small strait bladed screwdriver but it would be very tedious.


The first thing I discovered was that their were no holes in the case to allow the sound to get out. If I could make a few holes in the case it might make it quite a bit louder.
Remove the 3 screws in the shell and gently pry up the shell. It tends to bind at the top. I believe the housing for the led is what causes this. just take your time and it will come off.

Here is an image of  the device once I opened it. click on the thumbnail for a larger image.
inside the motion sensor Circled in green is the speaker. Lift the speaker up out of the center of the clam shell and also lift up the circuit board. I ended up removing the circuit board too. If you do this you will need to get the reed switch positioned correctly when you replace the cicuit board so that it is just under the contact attached to the batteries. there is a little plastic holder for the reed so make sure it is situated within that.

Take a dremel or small drill and drill several small holes into the center of the clamshell. Neatness doesn't count as long as we make a way for the sound to get out. Now put everything back the way it was. and put the shell back on. When i did this the clear led housing always turned a bit and wouldn't line up perfectly with the holes in the housing. Just take a small flat bladed screw driver and push up on the little ears until they pop into place between the 2 shells.
Don't try to drill these holes without removing the speaker first. The speaker has a very delicate membrane that sets right next to the shell. If you try to drill the holes without removing the speaker you will have made an ugly paper weight instead.

Here is what mine ended up looking like. Not pretty but sounds a lot louder.
motion detecter with holes

Of course this could just be the beginning of what you could do. You could snip the speaker off, add a jack to the shell, and use with an external amplified speaker.  Or possibly pur it in a bigger shell and replace the watch batteries with a 9volt battery.

Have Fun!