FIRST Pittsburgh Regional Robotics Competition

This last weekend was the FRC Pittsburgh regional. There were over 40 high school teams competing in the Frisbee-based competition, so the Peterson Events Center was packed with thousands of teenagers. I was there as captain/driver of City High's team, the Short Circuits (1743)  (as to why our team is named after an electrical failure, I'm at a loss). In short, it was the best robot our school has built and we consistently scored every match.

The competition lasted from Thursday to Saturday. Here is a basic schedule breakdown:

Thursday: Pass inspections and compete in practice matches

Friday: Compete in qualifying matches to develop a rank

Saturday: In the morning finish qualifying matches, in the afternoon are the final alliance selections and subsequent tournament

In fact, we were ranked first or second Friday morning and were in the top 10 90% of the competition. Our robot was one of the few to pick Frisbees off of the ground and most of the competition was just honing in shooting and dealing with small issues as they arose. These issues, like a broken belt or bad autonomous code, are dealt with the in pits:

Each team has a pit on the left side of the curtain and it is where they make adjustments to the robot or talk strategy. After a few devastating loses on Saturday morning, our team finished ranked 16th (the worst all weekend). This excluded us from be one of the alliance captains in the selections at noon and we were, furthermore, not one of the 24 teams to go into the tournament. But, because we were the top ranked team remaining we got to sit with our robot throughout the tournament in case there were any catastrophic failures in the other robots. 

And finally, all the mascots doing the Harlem Shake here.

Snow Day Tinkering

I had this old Sony boombox that used a lot as a kid to listen to Bruce Springsteen or Jars of Clay cassettes. It had a lot of buttons on it, several moving parts, and even a small LCD. What better way to make use of a snow day than to take apart old electronics?

I was thoroughly surprised by the amount of electronics inside the player. There's a main board, a power management board, an LCD board, a radio board, and several mechanisms for cassette and CD playing. 

The main board had several small trimmer potentiometers on it along with 2 much larger potentiometers. I desoldered one of each of those along with the small LCD to see if I could figure out how their wiring worked. This was fairly difficult to do and I was afraid the heat might ruin the LCD.

To test the LCD I used the 5 volt and ground ports on the Arduino and just made different connections on the screens 8 pins. There really weren't any consistent patterns that I could make out, but the screen was definitely working. I tried looking up a pin-out online, but there isn't much support for a 1 in by 1 in display from a 90's boombox.

There is, however, a lot more support for wiring up a simple trimmer potentiometer. The potentiometer as three pins, a positive, a ground, and the signal (the middle pin). This signal is analog in that it doesn't send 1s and 0s, it sends a variable voltage. Rather that research exactly what this signal looks like, I decided to use another great feature of the Arduino, the serial monitor.  It allows me to hook up a sensor into an analog pin and then print out all the numbers that come out. Doing this, the returns range from  0 to 1023. 

To put the sensor to actual use, I wired it up with an LED. LEDs can be programmed digitally (on or off) or through an PWM signal. A PWM signal essentially turns the LED on and off so fast that it looks like it has a partial brightness. This signal is given by a number from 0 to 255. In the code, I just multiplied the input from the potentiometer by .25 to get the proportional output to the LED. It is more elegant than using one or two different buttons. In the picture, the potentiometer is the little yellow circle. 

I tried to do the same thing with the larger potentiometers but when I hooked them up to the Arduino they shorted (even with resistors) and created a lovely smell. Thankfully the Arduino shuts itself off before it gets destroyed by my ignorance. 

To see the below wiring in more detail or to take a look at the code click on the Projects page and follow the subsequent links. 

Soon I will either put the DC motors to use by buying a motor controller or I'll purchase some servo motors which I can drive directly from the Arduino.

Fritzing!

I just found a great new resource for robot hobbyists called Fritzing. The folks there have created a great software that lets a hobbyist create visual or technical schematics of their circuits. Ideally, it will allow me to work on mapping out the electronics and ensuring their integrity without ever having to touch a wire. It should greatly increase my efficiency  as I'll be able to do the most difficult part of building circuits at school - planning the circuit out. 

Below is the schematic I just made for the 'Magic LEDs' project - it makes the wiring very clear.

For anyone interested, you can follow the link to download the software (which doesn't even require an install) here.

I will continue to use this software to map out any projects I work on in the future, including the main robot. You'll be able to see them on the project page (soon to replace the code page) which will include schematics, code, and links the the respective blog posts.

Fritzing also has compiled their starter kits for arduino boards, their own accessories, and great guides that utilize the community using their software. Check them out in the links page.

Also, look forward to future posts - I'll be working with an accelerometer for the Arduino and I'll launch a survey for your input into what kind of robot I should make.