I want to build a simple crystal radio receiver. I do not want amplify the signal received. I want to detect the presence of a transmitted signal, and then use the presence of the received signal as a trigger to switch on another device (battery powered). 
My knowledge is VERY basic, and I have been trying to learn more. I have found a schematic on the web. 



http://www.circuitdiagram.org/how-to-make-build-crystal-radio.html

Is this design suitable for my intended purpose? (minus the Earpiece)
From what I can tell, this receiver is made up of an inductor, a variable capacitor, and a diode. I am assuming my circuit would need a transistor switch as well. What else would I need? (I have assumed here that the antenna is part of the inductor coil - is that correct?)

I am looking for components I can use to make up this circuit.
I want to receive the signal across a range of 60 feet and I want the circuit to be small (>1cm). What else do I have to ascertain in order to start searching for the components I need? 

If anyone can to suggest suitable inductors, capacitors and/or diodes - this novice would be grateful!


Question: How to ask a question according to the specific sections?
Answer: What do you want to achieve by getting up early?  I get up early in order to catch the morning bus. 

What is your reason for wanting to get up early? I get up early because if I don't, I will miss the morning bus.

Note that the question can really the same: why?  The difference is how the answer is worded:


Why do you X? I do X in order to .
Why do you X? I do X because of .


I think your intended answers are based on the fact that you must catch the morning bus to arrive to work on time. 
 - I get up early in order to catch the morning bus. 
 - I get up early because if I don't, I'll miss the morning buss. 
 - I get up early so I can make it to work on time. 
 - I get up early because I want to make it to work on time.

Following is a bunch of examples. I'm not sure if it's just me, but it seems that often the "because" answer is kind of worded in the opposite sense of the "in order to answer".  It seems like "because" is the driving force or reason, and "in order to" is a goal state.  Also, the "in order to" answer seems more cold/clinical/unemotional/to-the-point while the "because" has more emotion and  a broader set of reasons.  I don't know if this is just me though:


Why do you eat hamburgers? I eat hamburgers because I like hamburgers.  
Why do you eat hamburgers? I eat hamburgers because [I'm trying | I want | I need] to gain weight.  
Why do you eat hamburgers? I eat hamburgers in order to gain weight. 
Why are you eating hamburgers right now? Because their only $1 each.
Why are you eating hamburgers right now? In order to save money; they're only $1 each.
Why are you eating hamburgers right now? Because [I want | I need] to save money, and their only $1 each.
Why do you eat food? I eat food in order to live. Note how well "in order to" answers an abstract question.
Why do you eat food? I eat food because I need to eat food in order to live. Not a great answer. 
Why do you eat food? I eat food because if I don't, I will starve to death. Because is using the opposite sense to mean the same thing.
Why do you eat food? I eat food in order to avoid starving to death.  In order to sounds more awkward this way than the first line.   
Why do you eat food? I eat food because I get hungry.  Because is more simple here, based on base emotion or desire.
Why do you eat food? I eat food in order to satisfy my hunger.  In order to has to carefully consider the goal state.
Why do you watch James Bond movies? I watch James Bond movies because I like James Bond. 
Why do you watch movies? I watch movies in order to gain enjoyment.  In order to is more cold/passive way of describing things.  
Why do you watch movies? I watch movies because it's fun.
Why do you smoke? I smoke because I'm addicted to nicotine.
Why do you smoke? I smoke in order to satisfy my nicotine cravings.
Why are you trying to quit smoking?  I'm trying to quit smoking because smoking is bad for me.
What are you trying to quit smoking? I'm trying to quit smoking in order to get more healthy.