Monthly Archives: May 2013

2.007 Recap (or How My Robot Will Beat Me At Operation)

Another great class. Since a fair number of my fellow MechE’s had robotics experience on their high school’s FIRST robotics teams, I came into this class feeling a little outmatched. I hadn’t had much Solidworks experience beyond making and cutting simple shapes, and I really had no experience building structures, joints, mounts, etc., all the practical bits that make mechanical things… well… do stuff. Nevertheless, if there’s one thing that MIT has taught me, it’s that diving in is the best way to learn. They give us the opportunity, we supply the effort.

And so we began. Thankfully, we started out with some tutorials in CAD modeling, as well as primers on some of the more useful mechanisms discovered in the past few millennia of engineering. We also had primers on electric motor modeling, tolerances and robust design with error margins, and a practical recap of the structures we learned in 2.01/2.02B.

With some mechanical basics under out belts, we started designing for the competition. The challenge this year was quite a throwback; Hasbro’s “Operation,” except blown up huge with Tim the Beaver, our fearless mascot, going under the knife.


The board has many differences, all in an attempt to give us a variety of tasks. One could extract a steel wrench from the ankle, perform a minimally invasive surgery on butterflies in the stomach, replace a torn ACL with rubber bands, remove some ribs (I still don’t have a clue what was wrong with them), expand a stent, or fMRI scan Tim’s “brain” to see what he is thinking. Whelp, the number of activities were nearly overwhelming. Add in the point values of each, though, and you can narrow them down pretty quickly.

2.00b is the Best Freshman Course Ever.

Meet us and our final project for 2.00b:
The Product and the Team

2.00b was an incredible class. Hands down, the best class I have ever taken. The amount of time and attention to detail that the staff put into making it a fantastic experience was obvious, and paid off. There were lectures on design, safety, fun (we literally tried describing fun and found ways to quantify a toy’s “fun factor” that DIDN’T seem totally ridiculous and mechanical) and ideation.

We were treated to special sections on casting, electronics, prototyping tools and a memorable trip to Hasbro HQ (I bought one of their freaking awesome lightsaber replica’s there on a courtesy employee discount, smartest business move ever 😀 ). Best of all, we were given a semester, tons of resources, brilliant classmates and opportunity for peer and advisor review to perfect the final project, a toy based on the theme “Imagination.” A broad theme for toys I grant you, but that allowed us to be as opened minded as we could when we plastered the walls with hundreds of toy ideas, from the lame to the insane to the unsafe to the few that became final designs.

Our group decided on making a kit that would let kids set up a high-tech laser security system, just like the ones in spy movies, in their own home, with visible beams and cool sound effects. As the only one on the team with significant electronics experience, I knew a lot of responsibility was going to fall on me to set up the guts of the toy, but I was pretty thrilled at the prospect. Since it’s a blog post and I don’t want to give away too many details, I’ll just give a brief overview.

I designed three different, totally wireless units, lasers and receivers, of which there are many, and a home base, of which there is one. Since safety was a major concern, I had to make sure that if a beam was ever broken, the laser shut off to be eye safe. Thus, I included a lot of safeguards in case of lost connectivity, normal broken beams from a child setting off the alarm, and a safe set-up setting so the lasers and receivers can be paired up easily. I also made each pod rechargeable so use would be convenient and wireless. To play, just stick the pods on a wall or tripod, aim a laser at a receiver, turn on the home base briefcase (which doubled as the carrying case 😀 ) and hit the big red button; the timer display counts up, and gives time penalties if you break a laser beam. Time yourself to improve you skills, or race your friends!

So much fun, making it and playing it! It was pretty gratifying too to be voted best toy of the semester. Hit the links for the presentation videos!
Our intro video:
200b Movie final

Our full presentation:
Laser Maze Presentation

Electric Keyboard on the Super-Cheap

Each year, MIT has a(n absolutely incredible) weekend of events for prospective freshman (herein referred to as prefrosh). Next Make always has an event to teach prefrosh basic soldering skills, how easy making your own electronic trinkets can be, and of course how awesome Next House and Next Make are!

This year, based on some inspiration from different sources, I came up with a way to make an electric piano at just a few dollars a pop. The results aren’t pretty for that price, but work well enough!

Essentially, you just draw on paper with graphite, the conductive material used in pencils. The graphite will have some resistance between two connected points, which varies with line thickness, layer height and distance. This resistance can be used with a 555 timer, which charges and discharges a capacitor to make an oscillating signal. The frequency is related to the time it takes to charge the capacitor, which depends on the resistance. The frequency of the sound depends, then, on the resistance through the piano.

About 40 prefrosh stopped by to make a circuit, the halls rang with 8-bit-esque sounds! For a moving sample of how to play the piano, our very own Eva plays piano.

Let’s make things.

Here are a few more links to help others with their projects. ABS
–Because one can never have enough ABS on hand

OSHPark Circuit Boards
–Circuit boards in really small quantities for an awesome price and fast, fast shipping. Prototyping dream come true!
–Some really cool specialty plastics, electronics, laserable metals… all sorts of neat things to beautify a project.

PCB Manufacturer Comparison
–A nice comparison of the quantities and sizes that make each small-order pcb manufacturer cost-effective.

And I don’t even get click through revenue!