Thoughts? (on rule points)

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Re: Thoughts? (on rule points)

Post by sean9keenan »

Primate wrote:Just a quick question on something the original poster pointed out. I've seen both photoresistors (LDRs) and photovoltaic stuff referred to as photocells, but they seem to specifically want something that produces a current, not just inhibits flow from a battery or similar. Does this mean I can just wire up a flashlight pointing to a solar panel?
You can definitely have a flashlight pointed at a solar panel to power your next circuit... at least as far as I can tell. I would just like LDR's in unrelated applications, because they can be very useful... and I believe they are cheaper then solar panels, even if they can't drive a current they can still be useful

just my 2 cents, and I still haven't seen any responses on the FAQ's or the Rule clarifications...

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Re: Thoughts? (on rule points)

Post by sirup96 »

LDR, in use with a batterys or other power sorce and the loads, act like a dimmers swich, no light sorce to the LDR it opens your circit. When there a littel light to them it lets a small amount go unless the load needs more to operate like a moter that can't rotate with that littel energy. As someone mentions the use of Black Box. I like the idea but it dose takes some fun out of it, but i would think that as long as you can open it and show its workings there should be no problem with it
.

Now what when they say you use a moter to create wind energy and it leads to the next action what do they wont with that?
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Re: Thoughts? (on rule points)

Post by binary010101 »

1. Spelling, please. Thank you.
2. Answering your question, it basically means "use a fan to push something".
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Re: Thoughts? (on rule points)

Post by DeltaHat »

The hardest thing I can see about using Solar Cells in a device is the limited voltage and current they deliver. The hobby-class solar cells I found produce between 15 and 30 milliamps at between 2 and 6 volts in direct, high-intensity sunlight. The sun is orders of magnitude brighter than a flashlight or LED.

You will have a hard time getting enough energy out of a solar cell in a competition setting to do any appreciable work with it.
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Re: Thoughts? (on rule points)

Post by fleet130 »

Solar cell output voltage remains fairly constant at approximately 0.5 - 0.6 volts. Higher voltages are obtained by connecting several photocells in series. Output current is proportional to the photocell's area and intensity of the light falling on it. (twice the area or light intensity produces twice the current) Since voltage is relatively constant, output power is also proportional to light intensity and area (P=IxE). A solar cell indoors produces only about 5% of its output in bright, direct sunlight. This means you would need 20sq inches indoors for every 1 sq in required outdoors (or a very bright light source).

You may find this article on Performance and Use of photocells informative.
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Re: Thoughts? (on rule points)

Post by Primate »

Yeah, I was thinking of having the power produced from the solar panel be used for an unlisted mechanical action. I know it's kind of risky to introduce another mechanical aspect, but I figured at least I won't have to worry about that rule clarification. (Can you even get a motor to run off of .5 volts? The random motors I have lying around hardly spin at 1 volt...)

The wind power also seems ridiculously unreliable to me. I'll probably end up sticking the propeller in an airtight box with a windmill to trip the next action. I can't think of anything easier--all wind does is move stuff, and blowing a car around or something seems likely to fail.
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Re: Thoughts? (on rule points)

Post by Flavorflav »

sean9keenan wrote:Bonjour,

I figured that I'd post some of the rule clarifications that we're sending in... and would like to hear what you think of them. While I realize that some of them are a stretch, I'd rather hear an answer then have to wander into planning without clarifications. I know that you guys can't make anything official, and we are sending them in, I was just wondering what your thoughts on these were. Note that I know that a lot of this isn't properly formatted for a clarification... and on a whole I think that some are definitely more critical then other clarifications, I also added comments below some of them.

1) As specified in the rules, points are granted for only whole seconds, is this true for point deductions, is it only a point off for a full second over(ie at regionals is 60.0 the same as 60.9)? Also for the second tie breaker, is this time measured only to full seconds? To then be broken by the third tie breaker? Or is it otherwise measured to the most accurate time measurement available?

2) Are Laser pointers that follow the specifications pointed out on the soinc.org website allowed on the device? More specifically are they one of the allowed electronics, and are they allowed to be powered?
Laser pointers and Lightbulbs are disallowed in section 3d, but lightbulbs are almost allowed in section 3g (see below clarification). They could be banned under the hazardous materials clause in 3e, but the soinc site says that they aren't hazardous if they are class II. Mainly, I like lasers... :D

3) Are lightbulbs allowed?
They aren't under the allowed list of electronics, unless you consider a light bulb a "resistor" but then why wouldn't a wire be a "resistor". It does later in the rules give flashlights a specific allowance of sorts (3g)... but flashlights are a combination of specialized resistors and gas, which could be considered a dangerous material.

4) Is the photocell specified in section 4b required to be the sole use of power for the motor? or can it otherwise act as a trigger?
I'm expecting that people will say that it has to be entirely powered, but it's worth a shot...

5) Are Light Dependent Resistors allowed to be used on the device, or are photocells limited to devices that produce a voltage?
I like LDR's (and they are cheap) but alas are not on the list of specified electronics, they would also be easier/cheaper to use then photocells for many of the same tasks

6)What are the specifications on "switches" are only certain types allowed, such as SPST, or limit switches?
The reason for this question is that technically some digital electronics might be considered switches (such as a schmitt trigger) but are clearly digital, while other mechanical implementations of a simple switch might not be allowed, because they are not "just switches" whatever that might mean. Personally I'm least worried about this one, but better to air on the side of being too safe then getting DQ'ed

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Re: Thoughts? (on rule points)

Post by StampingKid »

Pardon me if this is obtuse but is a solar panel a photocell? I see photocell in the tasks for mp but I donot see solar panel.
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Re: Thoughts? (on rule points)

Post by andrewwski »

Correct, a more proper term for a "solar panel" is a photovoltaic cell.
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Re: Thoughts? (on rule points)

Post by sean9keenan »

Still no response (unless my coach is with-holding information from me :? )

I don't know if this would be under FAQ's or Rule Clarifications though.... I suppose only time will tell.

I assume people are just going to be using lightbulbs then? I'm going to avoid LDR's for a bit, but I have some Light switch circuits from JYC that I would like to reuse... not to mention solar panels are a pain to use >.> I should get on that.

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