2004 DarkSabre MPC

From Science Olympiad Student Center Event Wiki

Articles in this series

Main Article
Descriptions of how to accomplish specific historic tasks and bonuses
A guide to programming with Lego Mindstorms and NXT
DarkSabre's 2005 ETL, illustrated with pictures and comments
The code for DarkSabre's 2005 MPC
DarkSabre's 2004 ETL, illustrated with pictures and comments
Information about acquiring and using Nichrome Wire
Diagrams, information, and uses for relays
Examples of Closed System Hydraulics
Examples of Photoresistor Use

This is Dark Sabre's Energy Transfer List (ETL) from Nats 2004. Added on are two columns (Picture and Description) to help explain what is going on. The pictures here have been cropped significantly to help show exactly what is going on. Many more pictures are available on the gallery here.

Note that the rules for the ETL have changed every year and the below should not be considered an example for whatever the current rules are.

This machine was not nearly as successful as my entry in 2005. This is mostly my fault, rather than the machine's. At nationals, I was nervous and over-volted my laser, which broke it (goodbye starting transfer). I also forgot to uncap the sharpie that was supposed to draw a figure-8 on the post-it. I also misaligned the squirt gun and it got water on a judge :P. Nationals was in Juniata that year and it rained. A lot. My static detector, which was a little gimpy to start with, failed completely. Needless to say, I went into 2005 having learned some lessons about building machines and not screwing up from being nervous.

No.ActionEnding EnergyPointsBonusPictureDescription
Playing card drops through slot onto see-saw, raising light barrierMechanical
1Laser shines through diffraction grating, breaking beam into primary, secondary, tertiary, etc dotsEMS1015
This setup was designed to satisfy a number of bonuses. The starting task was to drop a playing card into the machine. There was a bonus for using a mirror and also one for using the principle of diffraction. When the card dropped, it lifted a shield from in front of a laser, which then shined through a piece of diffraction grating and then one of the diffracted dots (not the primary laser path) shined on the light sensor.
Some dots reflect off of a mirrorEMS15
A secondary dot hits Lego light sensor which signals RCXElectrical
[RCX triggers motor]
2Motor turns Lego arm, hitting switchMechanical10
Hard to see here, but it isn't really important. Just a motor hitting a microswitch.
3Switch disconnects the electromagnetElectrical10
4Electromagnet releases metal ballMechanical1015
Electromagnet (magnet wire from Radioshack wrapped around a nail using a drill) drops a ball bearing into the seesaw.
Ball tips see-saw, raising permanent magnetMechanical
Magnetic switch is triggered by movement of permanent magnetMechanical15
Cow magnet on a window security sensor (has a magnetic reed switch inside that toggles in the presence of a magnet). Bought it at Radioshack.
5Magnetic switch completes circuitElectrical10
Electricity passes from an audio source (radio) through a 1:1 transformerElectrical30
This is actually a picture from my 2005 MPC, but I used the same setup. Use of a transformer was a bonus. The little green box on the left is a 1:1 transformer. Lacking an AC signal in the Mission box, I used a weather radio, which provided a working alternative. The green Lego box housed the LED that the radio powed via the transformer. The transformer is from Radioshack.
LED is litEMS
Light from LED triggers a Lego light sensor, which signals RCXElectrical
[RCX triggers motor]
Motor pushes trigger of the (non-flammable) air can, releasing pressurized airMechanical
The state bonus was for playing two consecuative, different notes on a harmonica. This massive rig held a compressed air can (for cleaning keyboards). I tried out a few brands until I found one that didn't use an ignitable propellant. The upper motor pressed in the trigger of the air can, which blew air through one note and tipped over the orange arm (right side) to cover a light sensor. This triggered the motor at the bottom, which switched the pneumatics to play a second note and then disengaged the air can.
Air pushes arm over a light sensor [plays first harmonica note]Mechanical
Change in light triggers light sensor, which signals RCXElectrical
[RCX triggers motor]
Motor turns and switches the air flow through a pneumatic switchMechanical
Air pushes second arm over, rotating axle [second harmonica note plays]Mechanical50+50+15
Change in position of arm's axle triggers rotation sensor, which signals RCXElectrical
[RCX triggers motor]
Motor turns arm, hitting a switchMechanical
Circuit is completedElectrical
6Nichrome wire increases in heat, lighting the candleThermal1015
The candle is actually not present here, but it was a tea-candle and rested between the two alligator clips, which held a piece of Nichrome wire that was wrapped around the wick.
7Candle burns natural fiberChemical10
8Formerly suspended weight is droppedMechanical10
There were two bonuses here, one for storing energy in a spring and one for releasing energy from a spring. Neither were allowed to be "spurs". The weight it shown hooked onto the hook from which it would usually be suspended with fishing line. You can see one of the alligator clips that held the Nichrome wire. When the weight was released, it fell down the tube and compressed a fairly powerful spring (storing energy in a spring). Underneath the spring was a momentary switch, which was in turn depressed by the spring. The spring then lifted the weight (releasing energy from a spring) and the switch at the bottom was released. This oscillation happened a few times. The switch at the bottom controlled a solenoid, which was pressing and releasing a touch sensor as the switch at the bottom of the tube was pressed and released. The RCX program counted the number of press/releases and would only trigger the next transfer after x cycles. This demonstrated that the spring's oscillation and sequential storage and release was vital to the operation of the machine.
Switch is depressed by weight's weightMechanical
9Circuit is completedElectrical10
10Nichrome wire increases its heat, melting the fishing lineThermal10
Weight is dropped, storing energy in the springMechanical30
As the spring releases its energy by depressing the switch at the bottom of the tube, it lifts the weightMechanical15
This is repeated, pressing the switch and completing the circuit multiple timesElectrical
Solenoid alternately depresses and releases touch sensorMechanical
Touch sensor sends signals to RCXElectrical
[RCX triggers motor]
Motor lowers the cathode into vinegar jarMechanical
The first part of the Chemical Battery bonus, the copper pipe was lowered into a vinegar jar to complete the battery. This was also where I manually adjusted time for how long the device would run. The higher up the pipe, which lowered very slowly, started, the longer the device ran.
11Anode, cathode, and vinegar reactChemical10
A vast improvement over the 2003 Mission, I used an ice cube tray with copper and zinc metal strips. I believe each side was in series with itself and in parallel with the other side. Regardless, it generated enough current to power the LED featured below.
Reaction produces voltageElectrical15
12LED turns on, shining on light sensorEMS10
Low-current LED from Radioshack, housed in an enclosed Lego box.
Light sensor signals RCXElectrical
[RCX triggers motors}
Pen and paper drives move in coordinated motion to draw a figure eightMechanical100
The National bonus that year was for drawing a figure-8 on a piece of paper. This was a two-axis drawing machine I built that I could attach a sharpie too. Just programmed it to draw the shape I wanted.
Movement of the paper drive activates a touch sensorMechanical
Touch sensor signals RCXElectrical
[RCX triggers motor}
Motor spins PVC pipe against rabbit furMechanical
Static charge is built up via the mechanical transfer of electronsElectrical
The "Static Detector" detects change in static potentialElectrical30
There was a bonus for using static. This rotated a PVC pipe against the "fur" of a fake mouse toy. Sorta visible is a resistor and a Field Effect Transistor, which acted as a rudimentary static detector. This triggered a low voltage LED.
Circuit is alternately completed and broken by DetectorElectrical
LED flashes on and off repeatedlyEMS
Repeated change in light is sensed by Lego Light sensorEMS
Light sensor signals RCXElectrical
[RCX triggers motor]
Motor turns, dumping Na2CO3 into jarMechanical
This is an example of chemical precipitation, which was a bonus that year. I kept the darker half of the solution, the ferric chloride, in the test tube (which had the light beam passing through it to the light sensor) so that it was demonstrable that it was not the color of the two components separately, but the actual precipitation reaction that triggered the next transfer. I got the ferric chloride from my chem teacher and the washing soda from the grocery store.
13Na2CO3 reacts with FeCl3 to make a semi-opaque precipitateChemical1015
14Precipitate blocks light source from light sensorEMS10
Light sensor signals RCXElectrical
[RCX triggers motor]
Motor dumps Ammonium Chloride pellets into waterMechanical
For the "Decreasing heat" bonus I opted for a chemical reaction in 2004. The 2005 solution is much more elegant. This dumped the pellets from the one-shot cold-packs you can buy at the grocery into a bin of water, which had a temperature sensor in it. The chemical reaction made the water quite cold and triggered the next transfer.
15Combination of substances results in a decrease in heatThermal1015
To speed the above reaction, I mounted the water bin on a rotating base, which swished back and forth rapidly, stirring the mixture.
Decrease in heat is sensed by temperature sensorThermal
Temperature sensor signals RCXElectrical
[RCX triggers motor]
Motor turns, changing position of pneumatic switchMechanical
Pneumatic piston pushes the trigger of a toy squirt gunMechanical
Water is hydraulically forced out of the toy squirt gun, runs down a funnel, and lands on candleMechanical15+15
The final task was to extinguish the candle that was lit earlier. There was another bonus for using a toy squirt fun in the machine. This did both: the pneumatic cylinder pressed the squirt gun's trigger and the water ran down the plexiglass, through the funnel, and onto the candle.
Candle is extinguished by waterThermal