Cause and Effect Toy 0

A defining feature of makers/hackers/diyers is having a junk pile—a collection of items they’ve saved from the landfill because they tell themselves “I might use this one day.” The maker lives for the day that their junk pile has utility.

My moment arrived when my wife (who’s a pediatric occupational therapist) was talking to me about one of her patients. To achieve therapeutic goals with the kids, she has to find activities to motivate them. These activities also need to be meaningful. They need to strike a balance between challenging and achievable. In this case, she was working with a boy who was unique. She tried using simple cause and effect toys to develop purposeful/functional movements from him but nothing seemed motivating enough. It seemed to his therapists that he didn’t understand cause and effect. The only consistent purposeful movements demonstrated with his hands were scratching himself or removing a blanket or shirt from covering his face. Searching for motivation, my wife found out that he loved videos from a kid’s show. He would pay attention to these videos for long periods of time, something he didn’t do in any other activities. Immediately, I thought of something I could do. I had an LCD screen that was being thrown away by a store and some components I could use to make what she needed. Once she got excited about it, she was able to get large buttons and switches that interfaced with other toys at work. So we came up with a clear picture of what she needed–a customizable display activated by a large button. Luckily, she talked me out of making it much more complicated.

The Display

The LCD was part of a product display being thrown away by a store. It has multiple button inputs, volume and brightness controls, an SD card slot, a USB port, and it’s powered by 12 V DC. Hooking it up through USB to the computer, it shows up as a storage device. There was a video on there, which helped me reverse engineer it. The five button inputs would play five different videos, but they had to be formatted specifically. PB1 played VideoA.avi, PB2 played VideoB.avi, etc. Additionally, videos could be played from an SD card.

The Button

It’s simple switch that connects to toys via a 1/4″ mono plug. The button also has a light, which requires batteries in the switch, but is not required to work.


The initial prototype was made with cardboard. The button input jacks on the LCD were four pin (two for input, two for power to illuminate a light in the button). However, I only needed the two input pins.

Faceplate with Bracket

I needed to make a stand for it. I worked with the TI Innovation Lab at the University of Central Florida to sketch out a design and CAD it for laser cutting. Below is what I went with. The legs are tightened with some threaded knobs from my junk pile with nuts inset in the acrylic.

Putting Everything Together

After laser cutting the face, I began to put everything together. As I began, I dropped the faceplate and shattered one side. I sawed that part off to leave me with one speaker. It worked out, because I only had one speaker anyway.

Everything was together and I just needed to give it some power. I decided on a 12V wallwart to supply power, but I needed to change the connector. Once I had the new connector on, I plugged it in, flipped the switch and heard a pop. Then the smoke started making its way out. I opened it up to discover a capacitor that had spilled its guts. I got the polarity mixed up. At that point, I decided not to deal with the plug, figuring batteries would allow for better portability anyway. I replaced the capacitor and used a battery pack with 10 AA batteries, regulated down to 12V with an LM7812.

The Results

Once it was finished, I gave it to my wife to take to work. She made sure that I wasn’t too optimistic about her patient using it. At best, she figured it would take a couple months before he learned how to use it and do anything with it. I told her that I would be happy if it just functioned. However, when she was at work, she called me and she was ecstatic. After a few minutes of showing him how to use it, he was doing it over and over again. They had never seen this kind of activity from him in all the years he’d been going there. It was great that it functioned. It was even better that it worked.

See this post for the next version, where I expanded the functionality and addressed deficiencies.