Mission Possible C

=Description and Scoring= Students will construct a Rube Goldberg -like device which incorporates many Energy Transfers and Bonuses to accomplish a given task. Specific rules have varied widely over the years, so this wiki attempts to address the more recent iterations.
 * A Target Time is given with optimum points being awarded when the devices meets the Target exactly.
 * A limited number of Energy Transfer points will be awarded based on the use of the 5 Energy Forms
 * Electrical
 * Mechanical
 * Heat
 * Chemical
 * Electromagnetic Spectrum
 * The machine must start and end with a specific transfer, this being the given task, which is heavily weighted for scoring
 * Limits are placed on maximum device dimensions, battery voltage, run time, and danger level of components.
 * Penalties are assessed for violating construction rules and for touching the device during operation.
 * Bonuses of varying points are awarded for completing specific sub-tasks within the device. This article focuses primarily on satisfying such bonuses.
 * Additional bonuses are available only at the State and National levels of competition.
 * An Energy Transfer List (ETL) is required to list the steps that the device performs and the energy forms involved.
 * The BEST machine will satisfy all construction requirements, have working transfers for the requisite number of energy forms and for all the bonuses, complete the main task, and do all of the above in exactly the Target Time.

=Theory of Construction= As with any building event, your actual approach depends largely on your resources, time, and expectation for success as a team. Regardless of those, however, Mission focuses tremendously upon reliability. A device may have all of the possible transfers, but if they fail to function properly, the participant will end up having to touch the device and will lose more points than the transfers were worth in the first place. This means that every part of your device must be designed to work repeatably and reliably, or it is not worth having it in the machine.

Solid construction is one way to improve reliability. Machines made carelessly of Legos, K-nex, or other toys have a tendency to fall apart during transport to competitions. Hot glue, while very convenient for testing your device, should always be reinforced or replaced with screws where possible.

For more complex machines that attempt to satisfy many of the bonuses, surface area within the device on which to mount transfers is often at a premium. Builders should consider using at least two side walls, which dramatically increases available surfaces without sacrificing accessibility. Three walled devices and multi-decker devices are common at national competitions, but make it a lot harder to access your device for setup and troubleshooting.

=The Energy Types= All action transfers must fit into one of the five basic energy types: Mechanical, Electrical, Chemical, Thermal, and Electromagnetic Spectrum. To receive points for a transfer, a conversion must be made between any two of the energy types, for example, a metal ball rolling over a set of contacts to close a circuit would convert mechanical energy into electrical. More information is provided for each of the five energy types below.
 * Mechanical
 * Electrical
 * Chemical
 * Thermal
 * Electromagnetic Spectrum

=Planning= Planning is the key to a successful mission possible. Assemble yourself a small group of fellow engineers and read over the rules a few times, brainstorming possible solutions to the given problems. Try to break the entire Mission down into sub-units that all have a common interface, such as electrical or mechanical. Make the sub-units solve one particular problem, like executing a chemical reaction. Breaking the design up makes construction and troubleshooting a whole lot easier. Once you have some basic "modules" thought up, draw what is called a block diagram to show how each module fits into the sequence. After the block diagram is complete, design ways to accomplish each individual task represented by a block in the block diagram. It is always best do design each module on paper before implementing it so that you know where you are going during construction. Do take note: then entire device must follow a single, linear path. Failure to follow this rule will incur heavy penalty.

Be conscious of timing when designing your device. Although it is hard to resist the urge to build a device that completes in less than three seconds, at a rate of twenty transfers per second, your judges will never be able to keep up; and if your judges cannot figure out what happened, you get no points whatsoever. Keep the pace down and extend your device out so that it is easy to follow.

Competition tip: Don't expect your judges to know you machine as well as you do. Be patient with their questions and make sure to tell them when your device is about to take an expected turn.

=Definitions and Terminology=

Mechanical
Mechanical energy is by far the easiest to use. Anything that moves, or has the potential to move, can be considered mechanical energy: from rolling balls, to fans blowing air, to releasing a spring. Here are some tips to help you use Mechanical energy successfully.


 * Above all, avoid gross mechanical at all costs! As cool as it looks to have your Mission Possible look like a game of mouse trap, avoid the urge. Of all the things that will fail on your Mission Possible, mechanical transfers will fail most often. Also, the more complex your mechanical transfers, the more time you will spend calibrating them so that they work just right. Another thing to consider transportation. The more complicated your mechanical transfers, the more prone they are to becoming misaligned during the movement to and from competition. It is a disheartening experience to have weeks worth of building and fine tuning go sour at competition because a part became unnoticeably misaligned. Believe me, I speak from experience.


 * Use as little mechanical as you possibly can. Use the smallest, simplest mechanical actions possible. An object barely has to move to be considered mechanical energy. Use small, surefire actions as your mechanical transfers. Do not make mechanical transfers the backbone of your Mission Possible.


 * Don't fight thermodynamics, or, let the machine do the work. If you have the option of having your device raise a weight or drop a weight, opt for dropping. When you let physics do all the work instead of your machine, you stand a better chance of success. This idea applies to all forms of energy as well.


 * Switches are your friend. Keep this in mind, anything that closes a switch is a mechanical transfer.

Electrical
Electrical transfers are incredibly easy to incorporate into your device, as well as the very versatile. There are a wide variety of products on the market that can convert electrical energy into just about anything. Electrical energy is also the safest of all forms of energy allowed in the Mission Possible. When properly done, electrical transfers never fail. Here are some tips to ensure your success with electrical transfers.


 * Learn to solder! Even though using wire nuts or terminal strips is a lot easier and less permanent than soldering, the quality of the connection is inferior and can lead to increased failure.


 * Get a good book and read it. To succeed in electronics, you have to know a bit about electronics. Radio Shack sells some excellent books on introductory electronics, well as the superb series, The Engineer's Mini Notebook. Especially good is Mini Notebook on sensor circuits. It tells how to make everything from pressure sensors, to tilt sensors.


 * Design before hand. Before you cut your first wire, design on paper how the circuit will work. Unless you are some electronics genius, you will need some kind of reference while constructing the circuits.


 * Cannibalize stuff. Go to yard sales and thrift shops and pick up various electrical gizmos to take apart. Things like printers and copy machines are excellent for getting various parts out of. One broken copy machine provided me with all the motors, sensors, switches, and wire I needed for my entire device!


 * Think carefully about batteries. If you are going to use any electrical transfers in your Mission Possible, you will need to make a few considerations about the batteries you intend to use. First, do you want to power each circuit separately, or use one central power bus? A bus is a bit more complex to build, but provides easier setup and reduces the chance of a single dead battery causing our device to fail. Using individual batteries for each circuit simplifies the design, but requires more maintenance. Second, how powerful do your batteries need to be? The more components you put on a battery, the more power the battery will need to deliver. If you are using high-amp devices like large motors or nicrome coils, you will need a battery with a high amp hour rating source the necessary power. For smaller things, like LEDs and IC chips, a nine volt or a couple AA's will suffice. Finally, What kind of batteries will you use? Standard alkaline batteries are fine for low to mid power applications. Alkaline batteries are the cheapest batteries, but once they die, you need to buy new ones. NiCad or LIon batteries make a good substitute because they are rechargeable, although they are a bit more expensive. For high power applications, a six volt lead-acid battery will do fine. They are expensive (approx. $20) but last a long time and are almost infinitely rechargeable. Whatever you do, do not use a car battery! Automotive batteries are way too powerful and the safety concerns they pose outweigh the benefits. If you do decide to use an automotive type battery, the positive terminal must be shielded, and all current must pass through a single 30 amp fast-blow fuse, else immediate disqualification. Consult your rule-book for exact specifications.


 * Replace/recharge your batteries before your official run. This is just a good idea and will save a great deal of potential heartbreak.

Electromechanical Relays
Relays have many uses. An electromechanical relay uses the magnetic field produced by an electrical current flowing through a coil to close one or more mechanical switches.



A few uses for relays are:

1. Control a larger/smaller voltage/current with a smaller/larger voltage/current. 2. Holding or Latch circuit to �capture� a momentary input signal 3. As building blocks in basic logic circuits 4. Isolate the input circuit from the output circuit

The Holding Circuit (or Latch) has commonly been used in MP to turn on a device with a momentary signal. A brief electrical pulse actuates a holding circuit which keeps power applied after the pulse has ended. For discussion, we�ll use a ball rolling into an elevator to be raised to the top of the device. As the ball enters the elevator, it depresses a lever closing normally open contacts of a switch mounted on the floor under the elevator. As the elevator rises, it lifts the ball off the switch, releasing the lever and allowing the contacts to open. The drawing below shows the basic holding/latch circuit. To simplify the diagram, both the relay coil and Device Under Control use the same battery.



First Diagram: Electricity cannot flow to the Elevator (Device Under Control) because of the normally open contacts of switch (S1) and the relay. Second Diagram: The ball rolls into the elevator, closing S1, energizing the relay coil and starting the elevator. Third Diagram: The elevator lifts the ball off S1, allowing its contacts to open. Normally this would break the circuit and the elevator would stop; however, the closed relay contacts continue supplying current to both the relay coil and the elevator.

This works great, but sooner or later the elevator reaches the top. If it continues to run, it could cause physical damage or waste energy from the batteries. Our next circuit addresses the problem.



In this circuit we�ve added a normally closed switch (S2). Its purpose is to stop the elevator when it reaches the upper limit of its travel.

First Diagram: The ball has just rolled into the elevator closing S1 and starting the elevator. Second Diagram: As the elevator rises, S1 opens, but the latch circuit keeps the elevator on. Third diagram: When the elevator reaches the top, it opens the normally closed switch S2, de-energizing the relay and stopping the elevator. Since the relay contacts are now open, closing S2 will not start the elevator again.

A switch that prevents a device from exceeding specified parameters is called a �limit switch�, regardless of what type it is. Lever switches and magnetic reed switches are particularly well suited in these applications.

The Loop-Back Circuit And finally, the last circuit! Sometimes it�s desirable to have several devices in series. The circuit below shows how each device can turn off the preceding device. This is sometimes called a �loop-back� circuit.



Switches S1, S2 and S3 and the normally open relay contacts prevent any of the devices from running.



A mechanical action closes switch S1, energizing the 1st latch, starting the 1st device.



1st device continues operation, even though S1 has opened.



The 1st device completes, closing S2, energizing the latch, turning off the 1st device and starting the 2nd device.



2nd device continues to operate, even though S2 has opened.

2nd device completes its action closing S3, energizing the 3rd latch, turning off the 2nd device and starting the 3rd device.



3rd device continues to operate, even though S3 has opened.

3rd device completes its action, openings S4, releasing the latch and stopping the 3rd device. Since none of the relays are latched, none of the devices will operate, even if S4 closes again.



Next: Add a circuit to return the elevator to the ground floor after the ball leaves the elevator at the top.

Chemical
Chemical transfers may look hard to the casual observer, but in all actuality they are not. Burning anything is a chemical transfer, so is the timeless baking soda and vinegar trick. For the best chemical transfers, as well as most of the chemical bonuses, you have to think creatively. Your local chemistry teacher is an invaluable resource in your quest for the chemical transfer.


 * Safety first! If your going to get DQ'ed for a safety violation, this is probably the place. Generally, if a chemical would constitute a hazard in the lab, it will be a problem at competition. Acids, unless very very weak, are almost certainly a problem. If you have any questions about the safety of your chemicals, asking your event supervisor or someone on the scioly.org message board is a good idea.


 * Where should I start? Here are some questions to ponder when brainstorming chemical reactions.
 * What reacts to make gas, and what can you do with that gas?
 * What reacts to make heat, and can that heat be detected or used to do something?
 * What reactions produce a precipitate? What does that precipitate do to the opacity of the reagents?
 * What does it take to make light, and how would you detect it?


 * The next step: Implementation. Once you have decided on what chemical reactions you are going to use, you have to figure out how to implement them in a safe and rule abiding manor. Take into account any rapid changes in volume. Baking soda and vinegar work great for making gas, but a lot of foam is produced. If this foam spills in an uncontrolled fashion you could be DQ'ed. For most reactions, containment is the best approach. By containing the reaction in a sealed container, you remove all chance of a spill. Also, when a reaction is contained, you can use just the volume change to trigger the next transfer.


 * Your chemistry teacher is your best friend. I cannot emphasize this enough: make friends with your chemistry teacher. A chemistry teacher makes a great consultant during the design phase, as well as providing access to the chemical storage room.


 * Be careful about elevation! Changes in elevation will effect the timing of your chemical reactions. Take this into account when calibrating your device.

Thermal
Thermal reactions are right in the middle as far as difficulty and complexity, but with a little creative thought they aren't that hard. Thermal energy transfers incorporate changes in - you guessed it - temperature. The change can be either an increase or a decrease.


 * Combustion is heat. Yes folks, before anything burns, it's temperature must be raised to exceed it's ignition point, thus making a thermal transfer.


 * Use the Peltier Effect my son... The Peltier Effect Thermoelectric Cooling Module is really cool and can be purchased from almost any surplus catalog. When power is applied, these junctions get hot on one side and cold on the other. A lot of potential here.


 * Use radiant heat. Radiant heat is also a possibility when looking for a thermal transfer. If you can melt something with radiant heat, you could trip off a mechanical transfer.


 * Consider exothermic and endothermic chemical reactions: Chemical reactions that produce or consume large quantities of heat can constitute a thermal transfer if properly detected. Exothermic and endothermic reactions also tend to be used for bonus points.


 * The Nicrome/Match trick: When nicrome wire is used to conduct electricity, it gets really hot. Hot enough to ignite a match or cut a string.


 * Be careful of humidity! I have learned the hard way that humidity can reduce the reliability of match combustion. Store your matches in an air tight container with silica gel packs found in new shoes.

Electromagnetic Spectrum
Electromagnetic Spectrum is by far the hardest transfer to get. At the regional and state levels, it is not uncommon to find devices with little or no EM in the device. Don't be ashamed if your device doesn't have any EM, but realize that nationally contending Missions have as many as the rules allow.


 * EM IS NOT AN ELECTROMAGNET!!! This is a very common question asked and a source for constant controversy. Electromagnetic spectrum involves the transmission of electromagnetic radiation, not the generation of a magnetic field.


 * EM is versatile. All forms of light and radio waves constitute EM, thus a remote control car and a light activated switch are acceptable.


 * Be very creative. Electromagnetic energy is everywhere. Servo units from a hobby shop will work. So will a small remote controlled toy. There is an entire field of electronics called optoelectronics just waiting to help you. A very good source for optoelectric circuits is the Engineer's Mini notebook - Sensor Circuits found at your local Radio Shack.

Black Boxes
Beware of the black box! A black box is any device that is self contained and pre-manufactured. You cannot declare the internal workings of a black box on your action transfer list, unless of course you want to loose points. Black boxes fall into two categories: x-to-x and x-to-y. A common example of an x-to-x black box is a relay. Relays work like electrically controlled switches, closing one circuit when power is applied to the input coil. Relays are x-to-x because they use electricity as both their input and output. This class of black boxes are considered "invisible" by the judges and you cannot include them in your action transfer list. For example, the following sequence would not be valid on an action transfer list: electricity causes electromagnet in relay to energize, energized electromagnet causes reed to move, moving reed closes switch in relay. The x-to-y black boxes can be included in your action transfer list, provided that you only list their input and output. An example of an x-to-y black box is a remote control transmitter. It converts the mechanical energy of pulling the trigger into electrical energy in the internal circuits, and that electrical energy creates an electromagnetic transmission. The electrical transfer within the transmitter cannot be used because it lies within the inner workings of the black box. A good rule of thumb is, if you didn't build it, you can only use it's input and output.

Note: Do not confuse a black box with stuff that happens in a box that happens to be black. If you need to run a transaction in a light-proof box, feel free. Just make sure that the box can be opened to show the judges what happened.

The Energy Transfer List
Energy transfer lists are your interface to the judges, and thus, very important. Whatever you put on your list will be counted towards your score. The list must be accurate because any deviation in your list from the actual machine will result in lost points. From my experience, it is best to hold off on making you list until right before the deadline so that you don't trap yourself when you need to make changes. What follows are some pointers on how to be successful when writing your action transfer list.


 * Don't be late! The judges will not accept a late list, which means you will either loose points or be disqualified altogether. Trust me, no matter how convincing your argument, the judges will not bend on this one.


 * Be neat. It's just good practice to make your list look good.


 * Be accurate. Every incorrect line in you ETL will cost you points.


 * Follow the procedures mandated in the rules. The three column approach works best. The left column is for the starting energy form, the middle column is for the action that takes place, and the right column is for the resultant energy form. Note: Excluding the first and last transfer, every line must start with the output from the previous line. An improperly formated list will cost you points.

START quarter is dropped --- M      M - quarter connect switch -- E      E - power ignites magnesium - T      T -- heated magnesium sets off thermite - C      C --- Thermite creates light --- EM      EM - intense light powers photo cell  E      E -- Power activates Jacob's ladder, making heat and launching ping pong ball --- T      T  heat ignites rodent -- C      C -- Burning rodent runs in tread mill -- M      M - rotating tread mill tips vile, spilling ammonia into clorox - C      C  Pressurized chlorine gas shatters glass container  M      M --- flying shards impact lever, launching ping pong ball and closing switch --- E      E -- power activates 1000w spark gap transmitter --- EM      EM -- interference interrupts TV reception -- E      E  screwed up TV makes toddler have tantrum - M      M -- sound from toddler trips circuit --- E      E - circuit rings bell -- M      M  sound from bell activates Pavlov Dog, causing drool -- M      M --- drool fills cup, tripping liquid sensor --- E      E --- motor turns launching ping pong ball  END
 * Here is a sample list: Check your event rules for exact formating specifications.


 * Only include relevant information. On your list, it is only necessary to document the energy changes within your device. If you have five mechanical transfers in a row started by a chemical and ended by an electrical, you can consolidate them all into two steps: chemical to mechanical, and mechanical to electrical.


 * Document your bonuses. If you include a bonus in your device, document it in your action transfer list. This way the judges don't have to guess weather you are employing a bonus.

=Transportation and Final Shakedown= Without an effective method of transportation, all of your hard work could end up being for nothing. Even then, once you reach your destination, it is very advisable to run a test run or two, just to make sure everything works as it should.


 * Do not use a courier to ship a mission possible! Even if you pay for a great deal for insurance and the best shipping plan, the middle-men within the company are not paid anything extra. Thus, they really don't care if your box is labeled "EXTREMELY FRAGILE!!!!!" Instead, use a straight line shipping service. A really great idea that I have been told is to ship via Greyhound Bus - the package never leaves the vehicle the entire way there. Or, if you are charting a bus, bring the Mission with you.


 * Build a sturdy crate. A wooden box to encase your mission is just a good idea. Half inch plywood works great.


 * Secure your device to it's crate. That way it won't get crushed if it is turned upside-down. Wood screws work best to mount a mission into a box.


 * DO NOT BRING CHEMICALS ON AIRPLANE CARRY ON! I have learned from experience, airport security does not like chemicals, especially oxidizers. If you need to bring chemicals with you, ship them out or arrange to buy them at the other end. It is also not a good idea to bring any fragile parts that even resemble anything potentially hazardous. Batteries are another thing that cannot be brought on carry on. You can check these things if your feeling dangerous, but if they are found, they will almost certainly be confiscated.


 * Run a pre competition run. I cannot stress this one enough. Geographic changes, such as elevation, temperature, and humidity can affect the performance of your mission possible, especially chemical transfers. Run a pre-competition run to make necessary adjustments.

=Battery Choices= Alkaline:
 * Advantages: Low per unit cost. Highly available. Wide variety of useful voltages.
 * Disadvantages: Non-rechargeable. Must be replaced periodically. Mediocre-low Amp Hours.

Zinc Carbon (Heavy Duty/Common non-Alkaline):
 * Advantages: Extremely low per unit cost. Highly available. Some variety of voltages.
 * Disadvantages: Non-rechargeable. Must be replaced constantly. Low Amp Hours.

Lead-acid:
 * Advantages: Rechargeable. Limited availability. Extremely low variety of voltages (Vast majority are 6/12V). High Amp Hours.
 * Disadvantages: Relatively high cost. Larger than most rechargeable batteries.
 * Buy one good 12V one (>10Ah) for around $30
 * Buy one good 6V one (>10Ah) for around $20

Lithium-ion:
 * Advantages:
 * Disadvantages:

Nickel Cadium:
 * Advantages:
 * Disadvantages:

Nickel Metal Hydride:
 * Advantages:
 * Disadvantages:

Interesting notes found in research:
 * Energizer batteries of equal voltage should last longer, given their specifications (more Ah).
 * Energizer Alkaline and Energizer Intustrial Alkaline have�suspiciously similar specs (same in most cases).

As you can see, Alkaline batteries have the most Ah of those 4 types. Alkaline batteries will cost twice as much as Zinc Carbons (the most common non-Alkaline battery), but they will deliver more than twice as many Amp hours. Thus it is always better to buy an Alkaline battery. They will last more than twice as long on the same equipment or will let you use higher draw equipment. Lantern batteries are wonderful for high-draw applications and should last quite some time. One of my teams used a pair of large lantern batteries in four machines over 6 years, the latter two years of which made significant use of nichrome wire.

If you or your school is looking for a cost-effective high power Mission, especially over multiple years, you should strongly consider a rechargeable lead-acid battery. A properly maintained lead-acid battery can last for years. It is a high initial cost, since you have to buy both a fairly expensive battery as well as a way to charge it, but you shouldn't have to buy another. I would highly recommend that you do some of your own research from manufacturer's websites on properly charging lead-acid batteries. If you do not charge your battery properly and in the right conditions, it can be both dangerous to you (nasty fumes) and can result in the loss of the battery.

=Programming with Legos for Mission Possible=
 * See Lego Programming for tips.
 * See Sample Mission NQC Code for Dark Sabre's 2005 nationals code.

=Coach�s Training for 2002 Ohio Science Olympiad Mission Possible Event= The following is a list of Do and Don�t items concerning the Mission Possible event.