Description
How to build AppMATes compatible cars from PEZ dispensers
Materials
- PEZ dispenser (cars2 edition)
- Knife, sandpaper
- Quick glue
- Double sided adhesive
- Conductive foam
- Conductive film
- Conductive glue
Development
Like many other kids, my son enjoys the Cars movies. He also likes my iPad so the Cars 2 AppMATes game was an immediate hit. The game can use normal touch control but the thing that makes it special is that you can buy miniature cars that drive on top of the screen to create an augmented reality. The only problem is that in Sweden, the delivery time is three to four month (see screenshot)! That’s quite a long time for a three year old… In order not to disappoint him during the wait I decided to experiment with the game. I know that the iPad does not have RFID or any other sensing, so the cars has to have a capacitive identity. Since both position and direction is detected I started playing around with three fingers closely together and quite soon I was able to drive a virtual car. Next step was to build a prototype:
I cut three small pieces of conductive foam (the kind of black foam that is protecting integrated circuits from ESD) into 5-6mm diameter.
The foam was placed on the iPad screen. When I touched all three of them I was able to drive the virtual car. By adjusting the spacing between them, different cars were selected.
To create something that my son could hold I bought Cars2 PEZ dispensers.
The car was removed and the base cut off.
I made the bottom flat using sandpaper.
The hole was covered by a piece of plastic glued into place (also from the PEZ base)
Then I used an ESD bag (the metal looking semi transparent plastic, used for storing ESD sensitive components).
I glued the three pieces of conductive foam on the ESD film with quick glue and made sure that the spacing between them was the same as when I tested the foam on the iPad. To reduce the resistance between the conductive foam and the conductive ESD film I added a small amount of conductive adhesive between the parts (wire glue).
I covered the backside of the film with double sided adhesive and cut the film so it covered the base of the car and the sides (where you hold it).
The cars work as a charm, but I’m quite sure they will be replaced with the real ones when they arrive…
Disclaimer
Please note that this text only describes how the AppMATes game works and how a capacitive identity can be created. It is not intended for piracy. I think that the Cars 2 AppMATes is a great game and therefore I have ordered the cars. If you appreciate the game, do the same. Since the app is free, the developers will only make their living from selling the physical car toys. I do not take any responsibility for how this information is used, please don’t do anything illegal.
Make sure the iPad screen and the conductive foam is clean. I do not take any responsibility if you scratch or damage your iPad in any way.
Licensing
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
Love this idea. Very cool how you figured out that the different placement of the conductive foam identified the different Cars characters. A bit of a warning. I bought the App Mates for my 5 year old son for Christmas. By that evening, my iPad screen was scratched badly in several places. Quite disappointed with the toys. Your foam bottoms will no doubt be easier on the screen.
Thank you for the warning! Hopefully the foam will work better, but sooner or later I guess there will be a grain of sand there… Im thinking of a second version only using the ESD film (folded in 3d), but have to do some testing first to see if it works.
Nice one indeed. You could also find the miniature cars as surprises in the Cars series of Kinder chocolate eggs.
Great idea, I will check it out. Hope they can be found in sweden ;)