UPDATE Nov. 29th: Added base station mod instructions!

Anyone who was in elementary school during the 2000's probably knew someone who had one of these SpyGear tracker systems. In fact, if you had one, you were probably the coolest kid in sixth grade. Both my sister and I had one of these, and it was definitely one of our favorite spy toys back then.

However, in terms of real practicality, the sensors were huge and awfully conspicuous, which often voids thier usefulness in a super-stealth scenario. There is a need for sensors that would get the job done but not stand out.

For my first Instructable and Altoids project, I present to you, the Altoids Mini Motion Tracker. It originally started as a friday evening project, and I thought I would share it with you all.

EDIT Nov. 25th: Wow, featured Instructable and 1000 views! I'm honored! Thanks everyone! :D

The next step will tell you what you need to build this.
I hope you enjoy :)

Step 1: Materials Required

This list is separated into Materials and Tools

Materials

Altoids Smalls Tin (any flavor)
Ordinary Altoids Tin (also any flavor)
Spy Tracker System (Mine is the one shown on the intro step of this instructable. I cannot guarantee other brand's will fit in the Altoids tin.)
CR2032 or similar 3V button battery
2AA batteries (Optional)
AA battery pack (Optional)
Various Lightweight Wire

Tools

Philips Screwdrivers
Electrical Tape
Soldering Iron and solder
Desoldering Tool of Your Choice (I used a desolder pump)
Multimeter (Optional)
Drill
Hot Glue Gun
General hand tools (Pliers, Sidecutters, Files, etc...)

Step 2: Sensor Disassembly

The sensor is held together by two screws inside the battery compartment. Remove the battery cover and batteries, unscrew the body, then carefully separate the parts.
The sensor is held to the top piece by a screw. Unscrew it to make it loose.
Cut the power wires as close as you can to the battery terminals (alternatively, desolder the wires from the terminals). Cut the small antenna wire close to the big wire as well.

Step 3: Preparing the Altoids Tin and Sensor

Discard/Throw/Share/Eat the Altoids in the tin.

After washing it, cover the bottom of the Altoids tin in electrical tape. You can spend as short or as long of a time on this depending on your level of OCD, but the important thing is that none of the conductive parts of the circuit make contact with the tin. While usually the tins are initially coated with an insulating material, that insulator is easily rubbed or scratched off.

On my sensor the power switch was on the bottom of the circuit board. To make it fit I needed to unsolder the switch and solder it back on the other side. If you are sure that you soldered it well, move to the next step.
Otherwise, if you are unsure of your soldering abilities like me, if you have a multimeter use it to check that your joints are solid.

Step 4: Bringing the Sensor Together

By now you should be ready to bring sensor together. Drop the circuit into the tin. For me, it fit quite snugly. Begin to think about where you want to position your sensor diode. The picture above describes the location I put mine. I had to use the drill to make a hole in the circuit board (where there were no circuit traces of course!). I could then screw the diode back in using the same screw that it was holding it earlier.

After securing the diode, I marked where its edges were on the tin, then drilled a hole for it. Hopefully yours turned out better than mine. If its rough, you could use a file to grind it down, which is what I ended up doing later.

Step 5: Powering It Up!

At this point I attached a AA battery pack to the sensor. I couldnt find a CR cell that was charged at that time, however I can now confirm that a CR battery does work instead of a AA or AAA. I highly recommend CR batteries as they fit into the tin nicely.

I found the best way to secure the battery was to use electrical tape to tape the +'ve and -'ve wires to the battery, then to wrap a small elastic around it.

Step 6: Disassembling the Base Station!

Now that you have completed the sensor, its time to mod the base station!

Disassembly of the base station was not difficult, it only was held together by six screws or so. Unscrew them all and you should be left with what is shown in the second picture..

Cut the wires connected to the battery terminals to separate the two halves. Then unscrew the circuit boards from the remaining half. Our goal here is to completely separate everything from the shell half. In my own case, I ended up having to carefully peel off some hot glue that was holding the wiring to the plastic. Also, getting the speaker out involved using a flat head screwdriver through the crack beside the edge, and leveraging it out. I desoldered it from and removed the rest of the circuit first.

The third picture shows the separated items.

Step 7: Preparing the Base Station

After separating the circuit boards from the original plastic case, we now prepare to put the base station into the Altoids tin. Since there were a few different components, I will separate the instructions into different groups.

Remember, don't glue/secure anything permanently yet!

Power Switch/Reset Button
I wanted to have the power switch and reset button accessible from the front of the tin. To do this, the switch and button needed to be flush and sitting upright on the bottom of the tin, facing outwards to go into the hole that I will eventually make in the tin.
However, I hit a problem, and that was the wires connecting that board to the rest of the device also faced outwards, meaning I would need to find some way to get the wires around to the back. I thought about unsoldering all the wires, but then decided that making a hole at the bottom of the board (where there was no electrical traces) that i could stick the wires through was easier. See the first picture.

Next, measure out where the switch and button would be on the tin, and drill out holes for them. See the second picture for this. Once you ensure the switch moves freely and the button can be pressed from the outside, move on to the LED indicators!

LED Indicators
I wanted to mount the LEDs on the top half of the tin, and the long ribbon wire that connected them made it convenient to do so. Consider the location you want the LEDs to stick through. Measure out and mark down the spacing for them, then drill the holes. If you got it right, and used an appropriate size, the LEDs should stick snugly in the holes. See the third and fourth pictures.

Misc.
Mark down where you want to place the remaining components. I made it so my main board would be in the northeast corner, the switch on the south east, the battery on the southwest, and the speaker on the northwest. Drill speaker holes under where the speaker will go, and a hole on the tin wall beside the main board to allow the antenna to poke through.
I also cut a corner off the board (again, where there were no traces) to fit the curved nature of the tin.

Step 8: Bringing the Base Station Together!

From here, you should be almost ready to bring it together. Remove everything from the tin, wash it if necessary, then cover at least the bottom of the tin with electrical tape. Poke holes through the tape again if it covered any up.

Drop the components into place. Make sure the antenna makes it out of the tin through the hole you drilled earlier. Then, one by one, hot glue them into place. I decided I would glue them in a way that made it relatively easy to remove, yet still strong. See the photo to know what I mean.

There are many different combinations of how you could arrange this. My initial plan was to go with what is pictured in the first photo, however, upon realizing that the speaker of mine was still broken, decided to put less priority to it. Instead of getting its own corner, I lay it over the main board, and used the extra space for a AA battery back. The base station will work with a 3V CR cell battery, however, it will not last as long and I wouldnt recommend it. The base takes more power in the radios, as well as having a power indicator LED.

To save space, if you have one, a AAA battery pack will work just as well.

Step 9: Final Notes

Effective Range
Something to keep in mind is the range of this sensor. The original toy had an advertised range of around 75 feet. That was with fresh batteries, clear vision from base to sensor, and both having their foot long antennas in an optimal position. From experience we got a maximum of around 20-30 feet reliably with our toy.

The range on my current prototypes with fresh batteries is around 15 feet maximum in optimal conditions, which is rather impressive considering the antenna on the sensor is now nothing more than a half inch wire on the sensor and 3 inches on the base. T̶h̶e̶ ̶l̶o̶n̶g̶e̶r̶ ̶t̶h̶e̶ ̶a̶n̶t̶e̶n̶n̶a̶s̶ ̶o̶f̶ ̶b̶o̶t̶h̶ ̶t̶h̶e̶ ̶b̶a̶s̶e̶ ̶s̶t̶a̶t̶i̶o̶n̶ ̶a̶n̶d̶ ̶t̶h̶e̶ ̶s̶e̶n̶s̶o̶r̶ ̶a̶r̶e̶,̶ ̶

t̶h̶e̶ ̶l̶o̶n̶g̶e̶r̶ ̶y̶o̶u̶r̶ ̶r̶a̶n̶g̶e̶ ̶w̶i̶l̶l̶ ̶b̶e̶,̶ ̶o̶b̶v̶i̶o̶u̶s̶l̶y̶. This is not correct, as I found out later. There is a whole section of math dedicated to antenna length calculations.

The trick here is to figure out an antenna system that is both inconspicuous on the sensor, yet functional. If keeping the base station inconspicuous doesnt matter, you could easily increase the range by increasing the size of it's antenna. I'll continue playing around with designs to see what works best. If I find something that works better, I'll update this.

Smaller Sensor Hole
I'm going to see if I can take the diode out of the little plastic module its in and maybe make it so all that poke out is the diode instead of the big hole. I'm not entirely sure how these things work, (if anyone knows, please comment!) so I'll have to experiment with the other ones I have. Again, if I find a better option, I'll update this instructable.

Full Suite
If you wanted, you could continue and complete the set and mod more the remaining 2 sensors into Altoids Smalls tins. Maybe even have each sensor in a different flavor tin haha.

Other Random Things
The speaker on my base station broke a long time ago, so I'll want to fix that. But does anyone know how you could change the sound file it plays when a sensor is tripped? I have a feeling it would be a huge deal that is way out of my league at the moment, but I'm just curious if there is anyone that knows, or if its even possible.
...I'm just thinking... "CODE WINTERGREEN! CODE WINTERGREEN!"

Thanks!
Thank you for reading, and I hope you enjoyed, learned from, or built this project. As this is my first Instructable, please offer whatever constructive crit you can, be about my build, procedures, or writing. Thanks :)