Temperature Task

Flavorflav
Member
Member
Posts: 1376
Joined: February 5th, 2006, 7:06 am
Division: Grad
State: NY
Has thanked: 0
Been thanked: 1 time

Re: Temperature Task

Post by Flavorflav » February 28th, 2011, 2:48 am

ichaelm wrote:
craZ4soccr wrote:How can you get a thermistor to work without using transistors? (since they're illegal, right?) We tried using a relay but the relay itself seemed to inconsistent in the amount of resistance needed to flip the switch...
Yes, transistors are illegal, which means amplifying the minute changes in the resistance in a thermistor due to a temperature decrease in order to trip a relay is almost impossible. Technically it's doable, but I wouldn't count on a relay as a precision voltage sensor. I think either you'd have to abandon the thermistor, or create such a huge temperature change that it could be easily sensed by a relay.
Haven't tried it yet, but our backup plan is to wire four or five thermistors in parallel. Each is supposed to go from 1.5K ohms to 25, which I would think would be enough to trip the relay, ganged up.

User avatar
ichaelm
Member
Member
Posts: 440
Joined: October 23rd, 2008, 3:10 pm
Division: Grad
State: PA
Location: CWRU, Cleveland, OH
Has thanked: 0
Been thanked: 0
Contact:

Re: Temperature Task

Post by ichaelm » March 12th, 2011, 8:19 am

This new FAQ is pretty interesting: http://soinc.org/node/731

bwy
Exalted Member
Exalted Member
Posts: 65
Joined: December 22nd, 2009, 1:52 pm
Division: C
State: CA
Has thanked: 0
Been thanked: 0

Re: Temperature Task

Post by bwy » March 12th, 2011, 10:14 am

ichaelm wrote:This new FAQ is pretty interesting: http://soinc.org/node/731
Yeah, I'm not sure the whole nichrome/bimetallic strip thing meets the "spirit of the task" either

In which case I don't really see any way of doing this task. They're basically asking for ice cubes or cold packs... to do what?

User avatar
illusionist
Member
Member
Posts: 942
Joined: March 20th, 2010, 4:13 pm
Division: C
State: MI
Has thanked: 0
Been thanked: 0

Re: Temperature Task

Post by illusionist » March 12th, 2011, 6:34 pm

As someone else pointed out:
Using dry ice, place a quarter/other object vertically partially embedded in the dry ice, and when the ice melts (it melts very rapidly) it will cause the quarter to vibrate side-to-side.
2012-2013 Building Event Captain
Rule 7d. "Event Supervisors are allowed to break any competitors' devices" -bearasauras

yousmellchinese123
Member
Member
Posts: 96
Joined: March 12th, 2009, 8:00 am
Division: C
Has thanked: 0
Been thanked: 0

Re: Temperature Task

Post by yousmellchinese123 » March 12th, 2011, 9:10 pm

Has anyone seen dry ice at competition yet? o__o
2010 Events: Elevated Bridge, Mission Possible, Ornithology, Astronomy, Experimental Design
2011 Events: Mission Possible, Astronomy, Experimental Design, Tech Trek
2012 Events: Robot Arm, Astronomy, Experimental Design, Tech Trek, Thermodynamics

User avatar
Primate
Member
Member
Posts: 409
Joined: January 15th, 2009, 4:34 pm
Division: C
State: NY
Has thanked: 0
Been thanked: 0

Re: Temperature Task

Post by Primate » March 12th, 2011, 11:10 pm

bwy wrote:
ichaelm wrote:This new FAQ is pretty interesting: http://soinc.org/node/731
Yeah, I'm not sure the whole nichrome/bimetallic strip thing meets the "spirit of the task" either

In which case I don't really see any way of doing this task. They're basically asking for ice cubes or cold packs... to do what?
Why not? It's more than difficult enough to implement.

Thermistors are your other option.
events 2012 gravity vehicle, robot arm, thermodynamics, tps

JTMess
Member
Member
Posts: 104
Joined: January 14th, 2011, 6:45 am
Division: Grad
State: NY
Has thanked: 0
Been thanked: 0

Re: Temperature Task

Post by JTMess » March 14th, 2011, 6:30 am

How are you guys keeping the time down on the temperature task so it doesn't take too much time from the sand timer? Our bimetallic strip is taking about 38 seconds to cool, which makes the task not even worth the 50 points compared to the 76 points the sand timer cound earn in this time.
2014 States: Scrambler-2nd, Mission Possible-2nd, Experimental Design-3rd, Circuit Lab-3rd
2014 Regionals: Scrambler-1st, Mission-1st, Technical Problem Solving-1st, Circuit Lab-1st, Maglev-1st, Bungee Drop-1st
2013 States: Gravity Vehicle-1st, Fermi-8th, Maglev-1st

User avatar
Primate
Member
Member
Posts: 409
Joined: January 15th, 2009, 4:34 pm
Division: C
State: NY
Has thanked: 0
Been thanked: 0

Re: Temperature Task

Post by Primate » March 14th, 2011, 6:09 pm

JTMess wrote:How are you guys keeping the time down on the temperature task so it doesn't take too much time from the sand timer? Our bimetallic strip is taking about 38 seconds to cool, which makes the task not even worth the 50 points compared to the 76 points the sand timer cound earn in this time.
Find a different bimetallic strip, or cut it down (width/thickness, not length). Ours takes five seconds.
events 2012 gravity vehicle, robot arm, thermodynamics, tps

noahb1110
Member
Member
Posts: 3
Joined: December 27th, 2010, 12:47 pm
Division: C
State: WI
Has thanked: 0
Been thanked: 0

Re: Temperature Task

Post by noahb1110 » March 21st, 2011, 4:52 pm

My temperature task is nearly instantaneous, it take like half a second.

bwy
Exalted Member
Exalted Member
Posts: 65
Joined: December 22nd, 2009, 1:52 pm
Division: C
State: CA
Has thanked: 0
Been thanked: 0

Re: Temperature Task

Post by bwy » March 21st, 2011, 5:16 pm

noahb1110 wrote:My temperature task is nearly instantaneous, it take like half a second.
Are you going to just drop that hint without telling us what it is? ;)

Locked

Return to “Mission Possible C”

Who is online

Users browsing this forum: No registered users and 1 guest