As I'm sure you've realized by now, I'm not too experienced with such things.
My question is this: what type of switch could I use for automating camera control in place of the reed switch, and how would I need to implement it? It says in the post that I could use a transistor; would this work/be simple?
I'm sorry for my technological illiteracy. I'm very grateful for any help anyone can provide!
I do understand that they are NOT working in that diagram - if that's
the improved diagram I'd can't imagine the previous one!!
The diagram is meant to be for a reed relay (4-pin), but due to missing Fritzing
parts a reed switch (2-pin) has been substituted - because diodes are absent
it is designed for reed-relays with built-in diodes and < 40mA current drain.
I do understand that they are NOT working in that diagram -
I may be totally wrong here (shoot me down if I am - please), but isn't the original designer intending for the wire laid alongside the reed switch to supply the magnetic field to switch the reed switch when the relevant Arduino pin is made high?
I do understand that they are NOT working in that diagram -
I may be totally wrong here (shoot me down if I am - please), but isn't the original designer intending for the wire laid alongside the reed switch to supply the magnetic field to switch the reed switch when the relevant Arduino pin is made high?
Bernie
Getting enough amps from the national grid for that to happen will be a problem. Reed switches need quite a few ampere-turns (10 to 50) to operate so expecting to get that amount of magnetic field from only a part turn (straight wire) will take an amazing amount of current
You're probably right jackrae, so how (assuming he's shown the actual layout he says he used) is that design supposed to work?
I can only think that MarkT has it when he says the wrong parts are shown. Personally I'd be looking at that second option as a superior solution.
One thing is for sure is it won't work. I think he might have been looking for a reed relay rather than a reed switch.
He says:-
This uses two Reed Switches from Radio Shack for about $3 each — sure I could have used other types of switches or a transitor, but they use magnetism which is cooler
What does he think a relay uses?
Yes it will work if he has two magnets in his hand, he can even throw away the arduino.
WOW, thanks for the responses everyone! What a knowledgeable and helpful community!!
So, opto-isolators it is! I read enough about them to understand the (very) basics of how they work, my new question is this: I see that in the example using the octocouplers, his have 6 pins, but he only uses 2 on either side. Would it be possible to use a 4-pin isolator, like this one: https://www.sparkfun.com/products/314
and Grumpy_Mike, I'm afraid I have no clue about the difference between an opto transistor and an opto FET. What advantages would the latter have?
Thank you all again for the responses!
In case anyone's interested, I've attached a picture of the pieces of the whole project rounded up together. I'm trying to build a system where someone could type in a word, and the system would draw out the word with an LED while capturing it with a DSLR. I've still got a ways to go, as I'm sure you can tell!
I do understand that they are NOT working in that diagram -
I may be totally wrong here (shoot me down if I am - please), but isn't the original designer intending for the wire laid alongside the reed switch to supply the magnetic field to switch the reed switch when the relevant Arduino pin is made high?
Bernie
Getting enough amps from the national grid for that to happen will be a problem. Reed switches need quite a few ampere-turns (10 to 50) to operate so expecting to get that amount of magnetic field from only a part turn (straight wire) will take an amazing amount of current
Not only that, but those wires are only connected at one end so no current can flow in them.
Grumpy_Mike:
That would certainly work but it would still need a diode across the coil especially if driving it directly from the Arduino's output pin.
Grumpy_Mike, is this in response to my earlier question?
I thought we had. We gave advice on your problem, then there was a small distraction.
You said you would try something.
So it is up to you, did you try it? did it work?
I'm sorry, I didn't mean to sound ungrateful. You were all very helpful.
What I was planning on trying was using the opto-isolators, as in that second example I posted. The problem I had was that I wasn't sure if 4-pin ones would work, as the example uses 6-pin. I looked at the parts' datasheets and found that the 2 pins the example didn't use are the 2 pins the 4-pin version doesn't have, so I went ahead and ordered the parts.
They are in the mail now. I'll let you guys now how it works out!
So, the opto-isolators came in yesterday, and I just wired it all up, and told it to shoot. Nothing happened. I have the circuit set up exactly as in the schematic, except that I'm using 4-pin instead of 6-pin opto-isolators.
My question: should the circuit be working with these isolators, or do I need 6-pin ones? Here's the type I'm using: https://www.sparkfun.com/products/314
