Virally Communicating Stressballs


First of all, it is crucial to have the spectrum analyzer AND an antenna. That took me forever to figure out.

Since there has been SUCCESS, it has been documented in case it goes away.

Clip 1 (Right click and download)

Clip 2 (Right click and download)

Clip 3 (Right click and download)

Clip 4 (Right click and download)

The final versions of the circuits are also here:

TX Board (Right click and download)

TX Schematic (Right click and download)

RX Board (Right click and download)

RX Schematic (Right click and download)

More Circuit Talk

After a lot of testing and blowing out part (especially voltage regulators) I finally got the transmitter and the receiver to talk to each other! With lots of thanks to Hector for helping me out with that! Unfortunately, after using the scope and the spectrometer to take a look at the output pin of the receive chip, there seems to be some problem with the impedance matching of the motor with the overall circuit. That means that I'm probably going to add at least a mosfet and maybe some other power too, which would bring me to two batteries which is not going to fit inside the stressball ...

I suppose that I am going to have to accept that for now, however, the antenna is always going to be sticking out of the ball regardless. There will definitely have to be future work in redesigning a coil antenna or something that can simply go inside the ball. Also, there will have to be a better power source I think, although I haven't gotten anything to pull up the circuits yet.

Solenoids Not Strong Enough!

So, it turns out that the solenoids that I have are not strong enough to actually cause any sort of reaction within the stressball. I guess rather than try and find something that is going to work in the same way on such sort notice, I'm just going to use some toy motors with some current regulation. This also means that I'm going to have to add some sort of MOSFET to my circuit to drive the motor properly.

First Round Circuit Designing

After searching around for some feasible solutions for making my stress balls, I found some LINX RF chips that seem to be manageable in use. I decided to get some of these to use in my final project. They are also not too expensive although it would be much cheaper if I had time to make my own solenoids and test what was going on.

I made some first run circuit drawups. Essentially, I want to run the chips using a TINY 13 microcontroller. Later, if I want to send more degrees of freedom to my stressball or if I want to send a byte to my stressball, I can add that. Also, if the stressballs are used in a noisy environment, then I can add some sort of simple encryption to set the stress squeeze information apart from other things going on in the 418 MHz band

The following are some snapshots of my current design:

Board of Transmitter

Schematic of Transmitter

Board of Receiver

Schematic of Receiver

Detailed Plan

I have gotten some stress balls and have cut them open to take out the core and replace it with something that can contract. For now, I think that I will just be starting with two stress balls

Following, I am going to first try a solenoid with the IR circuit (with some help from Ken). Using the solenoid does not require a bit stream and can simply use one click as a blip to indicate that there has been movement. For now, the squeeze is still triggered by a button.

The stepper motor circuit that I printed out earlier this semester might be able to be used for more advanced settings, that is, more than one degree of freedom etc.

Here is the first try at the circuits. They don't quite work, however I am pretty sure that the schematic is correct so it will only require some debugging!


I have decided to make some stressballs that can communicate with each other. If I can successfully make two, I'd like to eventually make many more so that I can simulate a viral stress network for fun. In order to better demonstrate what exactly it is I'm trying to do, I'm made two blender animations.

Viral Stress Balls 1 (right click and download .avi file)

Viral Stress Balls 2 (right click and download.avi file)

There will be several parts to this project. I have narrowed it down to a few partitions (1) a mechanical job (2) a wireless implementation (3) a decision for the medium

For the mechanical portion, I originally thought to use some gears and motors or perhaps even a mechanism with a spring and a motor. However, after speaking to Neil, he suggested that I use a solenoid because it would give me the few degrees of freedom that I would need.

For the wireless implementation, I would really like to try and look into the Internet0 rather than using a Zigbee chip for example. An example of the uses of Internet0 is here In essence, it is bringing the internet nodes away from what we currently know as the Internet. Trying to implement one of Neil's devices would really allow for a lot of place for growth in the future. The video shows something with one degree of freedom. For the first prototype, I think that just having this degree of freedom would be excellent

For the stressball to be really attractive and have a usability appeal (such as in the Blender model), the medium would have to be convincing. While sewing a cloth shell is one possibility, I would really like to have the rubber feel of stress balls that we're accustomed to.