Toaster Charger

Charger Box

This project was started in Summer 2012 in order to build an object that would be able to transport robots safely, store them comfortably, and charge them effectively.

Building the Models
The project started with the vacuum form machine. It would melt an antistatic plastic and take the shape of whatever we place underneath. Due to the high temperatures (200-1000 F) required to form the plastic, it would be difficult to use real robots. I took the Solidworks model of the rone bot and cut it in half with the split feature. Also using the split feature, I divided the robot into .125" and .250" sheets of acrylic/wood so that I would be able to laser cut and bond the pieces in order to make a robomodel.

The Phlatformer
Using OEDK's new vacuum form machine, I thought it would be possible to make the molds we wanted. However, things did not go as well as I expected. Using four models, the mold came out thinning. Using six models, the mold popped meaning the sheet was expanding too much. One thought was that if we used thicker plastic, it would not thin because there is more material. However, this was a mistake as the skillet used to heat the plastic only goes to 350F which is not enough to form the plastic. After many failed results, we decided to contact a company.

Deco Plastics
We contacted Deco and they said we needed to make a plethem(?) box, basically a box that would be able to hold the models with holes near the edges to allow vacuum in tight areas. They would've charged us $300 to build but we knew it would be easy to build so we took on the task. A day later, we built the box and Gorilla Glued (at the request of Deco) the molds on the top; afterwards we drilled holes near the edges. A few days later, we went to pick up the molds and they charged us $100 to set-up the machine and $6 per PETG mold.

Electrical Side
The charger involves using 2 DC-DC converters and a power supply. I'll add more as I work on it.

Lessons Learned
A few tips about vacuum forming.
1. The height you are trying to expand should be the distance you have between parts.
2. The holes you drill in the plethem(?) box should be as big as the thickness of the plastic.

Phase Two: Box Construction
In Spring of 2013, a new charging box was constructed. It had a greater focus on mass production then the previous design. Originally due to the limitations of the charging boards a single box was going to hold 6 robots. However, once it became apparent that the charging block had the capability to supply two charging boards power in parallel the original design was changed and a 12 robot box was designed. This design was mostly hand cut and assembled though future iterations promise to require much less manual labor.

Phase Two: Electronics
Power is delivered to the charger through a bucket socket power brick. From there it enters two boards which distribute the power appropriately between 6 robots. The charging is facilitated by aluminum l-channels which when brushed against by the rone's charging prongs complete the charging circuit allowing charging to begin.

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