Mission Possible C

[cypressfalls Robert]

Hey guys, I'm so excited about mission possible next year, I've never done it before, although our team got first at nationals a few years ago , and I'm wondering what kind of energy transfer contraptions have been used before that were successful? I will be testing all throughout the summer to come up with some good ones

[Dark Sabre]

Haha...well, there's no guarentee that the new MPC will be anything like the old MPC, but you can look at some of this stuff...:

Check out the three subgalleries here:
Mission Possible C Image Gallery <-- kinda the evolution of three years of my Missions. The 2005 machine got 3rd at nats after a 3-way tie for first was broken, so I'd like to think it is pretty good. If you wonder wtf is going on in the pictures, I can explain the machines in general terms or the way particular transfers worked...whatever.

The Mission Possible C Wiki also has some useful overview information on how the event worked back then.

[Dark Sabre]

Ah, the old Mission P.....

My oldest son, Ben, was at Nats in '05, too. I can't recall how many "full points" boxes there were (DS and the other two who tied, plus a few more that didn't run perfectly). Ben's was a full points box, too, i.e., one that had all the required energy transfers, and all the bonus elements; it needed a couple touches - so only finished 18th.

I'm guessing the new rules will be designed to make it a bit less intense. Under the old rules, it was arguably the most intense, time and money consuming event of all. We put well over $1,000 in it, and hundreds of hours. Those that got a full points box to work successfully accomplished something truely amazing.

I dug back through some archived files, abd actually found Ben's energy transfer list for Nationals - it gives you a sense- one example of the kinds of things/kinds of transfers involved. Format when copied to here is a little funky, but, it will give you the picture:

Code: Select all

TRF#   Action Description   Ending Energy Form   Pts   Bonus
1   Magnet attracts steel bar, which moves up, contacting nail   MECHANICAL 1   10   
2   Nail and bar contact completes/energizes circuit   ELECTRICAL 1   10   
        SPUR-energized circuit activates recorder announcing school name (school name bonus)   (electrical)      50
3   Completed circuit continues device by turning on single light source, illuminating phototransistor via fiber optics   ELECTROMAG 1   10   
4   Light from light source (via fiber optics) changes state of phototransistor, completing circuit   ELECTRICAL 2   10   
5   Current flow in that circuit through Nichrome wire causes heat increase in wire (increasing heat bonus)   THERMAL 1   10   15
6   Heated Nichrome wire touching candle wick causes candle to ignite starting chemical oxidation    CHEMICAL 1   10   
7   Heat from candle flame melts plastic fishing line holding up a card that covers a phototransistor (line is shielded from heat of Nichrome wire)   THERMAL 2   10   
8   Melted line breaks, allowing card to fall, which exposes phototransistor to light from light source via fiber optics   ELECTROMAG  2   10   
9   Light from light source (via fiber optics) changes state of phototransistor, energizing circuit   ELECTRICAL 3   10   
10   Energized circuit passes current through Peltier Junction, reducing PJ temperature   (decreasing temperature bonus)   THERMAL 3   10   15
   Decreased temp of PJ changes state of thermistor in contact w/ PJ which completes/energizes circuit   (electrical)      
   Current flow in that circuit energizes home-made electromagnet (home-made electromagnet bonus)   (electrical)      15
   Magnetic field changes state of Hall Effect sensor, completing circuit through oscillator ___descr____   (electrical)      
   Oscillated current flows through isolation transformer (passing current through transformer bonus)   (electrical)      30
11   Current from transformer activates motor, which winds string,which stretches spring (storing energy in spring bonus)   MECHANICAL 2   10   30
   Stretched spring contacts two electrical leads, completing/energizing circuit   (electrical)      
12   Circuit activates solenoid,releasing coil spring-loaded lever (releasing energy from spring bonus)    MECHANICAL 3   10   15
   Lever opens valve, flows pressurized air against paddle on pivot arm; air moves arm (mechanical pneumatics bonus)   (mechanical)      15
13   Moving pivot arm swings attached mirror into path of light from light source via fiber optics, reflecting light onto phototransistor   ELECTROMAG 3   10   
   Reflected light off mirror changes state of phototransistor, completing circuit   (electrical)      
   Circuit activates electric motor, lowering Cu & Zn electrodes into cup of vinegar electrolyte   (mechanical)      
14   Electrodes react with electrolyte activating battery (home-made battery bonus)   CHEMICAL 2   10   15
   Homemead battery generates electricity(~0.9v @ ~ mA) which trips transistor, activating circuit   (electrical)      
   Activated solenoid releases mousetrap spring, causing swing arm to strike piezo-electric ceramic crystal    (mechanical)      
   Arm impacting P-E crystal produces brief electrical output (Piezoelectric effect bonus)   (electrical)      30
   Electrical output causes LED adjacent to phototransistor to flash light    (electromag)      
   Light from LED flash changes state of phototransistor, activating circuit    (electrical)      
   Circuit activates fan, rapid air stream flowing over top of vane reduces pressure on upper side, lifting vane arm (Bernoulli effect bonus)   (mechanical)      30
   Lifting vane arm breaks electrical connection btw arm and support fork, tripping transistor & activating circuit   (electrical)      
        SPUR-Circuit activates electric motor, which starts to shakes baby rattle (shake baby rattle >10 sec bonus)   (mechanical)      30
        SPUR : Circuit activates electric motor which winds up strings to tie overhand knot in shoelace (Nat'l bonus)   (mechanical)      100
   Circuit continues device by activating solenoid, which squirts Pb(NO3)2 solution in pipette into tube containing KI solution   (mechanical)      
15   Reaction creates solid yellow precipitate Pb(NO3)2 + 2 KI ==> PbI2+ 2 KNO3  (chemical precipitation bonus) ck?-in Nat Ex, wrong?)   CHEMICAL 3   10   15
   Precipitate blocks light from light source (via fiberoptics) from reaching phototransistor    (electromag)      
   Decreased light trips phototransistor, activating 555 timer circuit which delays then completes circuit to Nichrome wire    (electrical)      
   Current in circuit heats Nichrome wire, which melts string holding back spring-loaded lever   (thermal)      
   Melted string releases spring-loaded lever pushing squirt gun trigger, releasing water under pressure thru tube to syringe    (mechanical)      
   Water pressure pushes syringe plunger and moving plunger trips mouse trap trigger (mechanical hydraulics bonus)   mech      15
   Released mouse trap arm strikes ping pong ball, launching it upward through tube   mech      
   Ping pong ball exits device, then re-enters, lands & stops on adhesive-covered catcher, ending device run and timing         100
BONUSES DISTRIBUTED THROUGHOUT DEVICE            
 Single power source (12v Pb-acid automotive battery w/ 30 amp fuse & + terminal shield, in container box)            50
Single visible light source (12v halogen bulb) distributed by 3 fiber optic fibers to all 3 claimed electromag transfers             50
 Point Breakdown (this is for information only)            
Transfer points             150
Energy Demonstration Bonuses            620
Task Completion            100
Maximum timing points (60 seconds)            120
ETL submitted on time            75
ETL 100% accurate            25
30-minutes (or less) to prepare device bonus            50

[cypressfalls Robert]

is fire reliable in the device? like a candle for example.

[Dark Sabre]

One year the task was to light and extinguish a candle. I always used nichrome wire to do it, which worked consistantly...but there's not a whole lot of reason to use open flames unless a bonus/transfer specifically requires it. Like if you just need a "chemical" transfer you can use nichrome wire to burn through some natural fiber string or if you need a "heat" transfer, you can use it to melt through fishing line.

That's actually what these are:


The wire burns the string or melts the line, which releases a weighted arm...that presses a switch which both initiates the next transfer and turns off the nichrome wire for that transfer.

Historically speaking, you have not been allowed to use "flammable" substances like acetone or gasoline or the like, but are explicitly allowed to use things like matches, candles, and small rocket igniters. I always found rocket igniters to be prohibitively expensive, since they were one-shots, while you could use the same little length of nichrome wire for an entire season. I never used matches outside of my first year or candles except for the year that was the task :shrug:

[yousmellchinese123]

I look foward to joining my high school team and doing mission.
It's one of my favorite building events.
I reember the 7th grade memories

[Dark Sabre]

Oh, robotman asked what nichrome wire was on the chat, but I figured I would mention it here too if people didn't know.

Nichrome wire (or NiCr wire), heats up rapidly when you put voltage across it. It gets hot enough to light candles, matches, burn string, melt fishing line, melt foam, melt legos, etc. Like any other wire, it comes in different gauges. What gauge you want and how long of a piece you want to use depends a lot what kind of battery you have. Ideally you want a piece long enough or high enough gauge that you can leave it on and it won't break...if you use a piece that is too short or too thin then it will break rapidly and you'll need to put in a new piece...just a matter of experimentation. Too long of a piece and it doesn't heat up.

Places you can get it:
Online: Places that sell foam-cutting equipement like Pitsco carry replacement wire: 32-gauge, 18-gauge
Some toasters (particularly the bagel variety, rather than toaster ovens) use NiCr wire for the heating elements.
All of the hairdriers I have taken apart have used a long coil of NiCr wire as the heating element.

I'd recommend you go to GoodWill or whatever your local second-hand general store is and pick up a $5 hairdrier if you want some NiCr...take it apart and pull the wire and the bonus fan out. It will be coiled rather than straight like you get it on the spool, but you can straighten it out easily enough.

[gh]

If you are desperate and are in need of a heating element, you can boil a pencil for the pencil lead or buy mechanical pencil refills in various diameters.

[starpug]

If you are desperate and are in need of a heating element, you can boil a pencil for the pencil lead or buy mechanical pencil refills in various diameters.

I think it's pretty simple to just take apart a 5$ toaster and use the heating element there which is already hooked up. It'll be interesting to see how the rules change

[cypressfalls Robert]

I am already taking apart a toaster and testing, what I think is nichrome wire, and it is working well Thanks guys

[Uncle Fester]

To cut down on extra experimentation. . . think RATIOS when determining NiCr wire lengths. If you're using 12V and a piece of NiCr from a 120V hair dryer, the 12:120 ratio means that a piece 1/10 as long will get the same results (heat, current draw, longevity) as the full length at 120V. Obviously, different battery voltages will mean different ratios. Since THAT amount is quite a lot of heat, a somewhat longer length will mean lower temp as well as lower current draw.

Also, use as beefy of copper wire as you can for connecting. Heck, strip the case off 12 gage house wire if you can. Delta Hat and I have sen a few where telephone wire was as hot as the nichrome-- abd, bad, bad! Use the biggest batteries as you can, and use new alkalines for competition. if D's are allowed, use D's, and NOT AA's or AAA's. NiCr draws a lot of current.

And please be careful. I've seen a few pretty painful burns over the years.