May 8, 2014

Working Prototypes

An Altoid tin makes a good interactive whiteboard marker.

An Altoid tin makes a good interactive whiteboard marker.

At last we have a working prototype. It may not look like we intended, but it works. After all this research and design I thought it would be a good idea to make sure the LEDs work. So, I used an Altoid tin, some wires, an LED, and a battery to rig something up. We were excited to get something to work. We fired up the projector and the accompanying software, and…nothing.

It was a let down, but that is to be expected. It just opened up a whole new set of questions. Was the battery good? Are these the right kind of LEDs? Is the LED burnt out? Did something go wrong in the wiring? And how are we going to figure it out? If only there was a way to see infrared light so that we could know if it was working. Cue the internet. We googled “how can you see infrared light” and found this gem. It turns out the rear facing camera on your iPhone or iPad will pick it up. And guess what? The Altoid marker did work. It had to be something with how I was holding the marker. In order for it to work properly the sensor mounted on the¬†projector has to “see” the infrared light. I was holding the marker the wrong direction. I flipped it and it worked like a charm.

The camera on my phone clearly showed the light being on.

The camera on my phone clearly showed the light being on.

This lead to three important discoveries for us. 1. The circuit and the LED work. 2. We need to rethink how it will be held and the design of it. 3. We now know how to see the infrared signal when we need to. We decided that a simple redesign of the cap and moving where the switch will go will give us what we need.

It didn’t take long for the students to redesign the cap. They had a new one printed in about 20 minutes. After trying out our new soldering iron we rigged up a new prototype and had our first working 3D printed prototype. It still needs some modifications and a real switch, but it works. Now we are waiting for Amazon to deliver our switches and soldering our circuits together.

Our first working prototype. Still needs a switch.

Our first working prototype. Still needs a switch.

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