I have what is probably a very nooby question. I’ve just started learning about circuitry and I think this is within my abilities but I just want to clarify…
It’s powered by an 18v wall adapter. I’d like to put a SPST rocker switch into the circuit instead of having to plug the 2.1mm jack into the system every time I want the lights to be on. I see the red and black wires on the female end of the 2.1mm plug clearly. But I’m unclear on whether to put the switch before or after this connection. And also if I have to splice into the wall adapter cord.
I know that a rocker switch has 3 connectors but I’m a little unclear how it all should be wired. I could use some guidance but I also understand that this is probably too simple a circuit for people here to be interested. Like I said, I’m really new. Alternatively, if there’s a site that has the information you think I need, please pass it along. I’ve done a lot of searching online, but haven’t found an example of what I’m doing.
You would put the switch after the female plug, cutting into (generally) the + wire (most likely the red one). I assume this is inside of the model. The switch to be mounted inside or on the model’s surface (with the wiring inside) ? The switch does nothing more than either keep the 2 ends of the wire you just cut separate, stopping the current flow … or bring the ends together, as if they weren’t cut and thus allowing the current to flow.
Switches can vary but I’ll guess the center terminal is labelled common and you can solder (or otherwise attach) the red wire you cut, coming from the plug, to it. If you can find a terminal labeled NO (normally open) then attach the other end of the red wire, going to the rest of your circuitry, to it. When the switch is open the common and NO terminals are electrically separated. When the switch is on, they are electrically connected. If there’s a 3’rd terminal on the switch, it’s likely a NC (normally closed) one. It’s electrical operation is the reverse (vs physical switch position) of the NO terminal. It’s open when the other is closed and visa-versa.
If you can post a link to the particular switch or post a pic of it’s terminals. Also note if the switch has just 2 positions or has 3; as in up, center, and down. FWIW I’d say most SPST switches only have 2 terminals.
The wall adapter (unmodified) then stays plugged into the socket.
Thanks, guys. Very helpful. I think i’ll try Mee_n_Mac’s solution. Question: if I get an illuminated rocker switch, then I have to connect the NC terminal to ground, correct? And if I have an 18v wall adapter, are there specific specs I have to look for in an illuminated rocker switch?
Nice model btw. I’ve got a Star Trek Enterprise D (1/350) with custom lighting and sounds. Working on an NX-01 and have a ST: Voyager still in the box.
Thanks, codlink. I’d really like to learn the arduino so I can put sound effects and and motion into the model, but I think i’m going to save that for my next model – a studio scale x-wing.
Do I need to build in a resister before the rocker switch or do they include one inside?
With illuminated switches, they specify the voltage and current for the light and the max rating for the switch itself. You might find that 18V is less common than 12V… Check Ebay for starters…
What he said ^^^ re: an illuminated rocker switch. It might need special wiring compared to a normal SPST switch. Post details on the switch when/if you can.
Question: if I get an illuminated rocker switch, then I have to connect the NC terminal to ground, correct?
Hmmm, not so fast. The other terminal is likely not an NC connection and instead something different. Having said that you will need to provide a ground connection to the switch to make it illuminated when switched.
So let me also just mention that I’ve seen model makers who want to hide the on/off switch. One clever (so I thought) way was to use a magnetic reed switch to do the deed (for low power models). Then what you’d do is stick (or not for off) a magnet in a place near the (inside) reed switch. The magnet possibly being distinguished as something else.
But ignore the above if you want, part of “our job” here is to complicate any easy design ! :twisted:
The second one is rated only for 15v DC (and it has a 2.1mm barrel plug to make things easier), where as the first one says it’s rated at 120 VAC. I’m still learning about current, amps, and ohms. Any advice you guys have would be really helpful.
Interesting idea about the magnetic reed switch. I’ll have to look into it.
Thanks, oldtemecula. That’s a good suggestion. However, I kind of want to use this as an opportunity to learn how to wire a switch into the circuit. I’m reading up on voltage, resistance, and current. I think the first switch I listed should work… it seems like it’s rated to be used with AC wall power and I’m only using an 18v DC adapter (which is less charge, correct?). So it should be fine, right?
I chose a rocker switch without a LED. It’s rated for 120VAC and 15A. If I understand correctly it can handle up to that amount of current and voltage. My wall adapter only puts 18v and .83A so I should be fine, correct?
And it has two connectors on it so I will split the positive/red wire and attach those two the poles. I hope I’m right about all this. I’d hate to blow all the work i’ve done inside the falcon. I think I might learn how to use a multimeter today and test it all out before I wire it up.
senorjacob:
I chose a rocker switch without a LED. It’s rated for 120VAC and 15A. If I understand correctly it can handle up to that amount of current and voltage. My wall adapter only puts 18v and .83A so I should be fine, correct?
In this case you should be OK. A switch may have very different AC and DC ratings. A lot depends on the type of load being switched. A rule of thumb is that when all you have is an AC rating, the switch can be used at the specified current rating for up to ~30V. Your case is sooooo very far from the ratings, it's a don't care situation.
senorjacob:
And it has two connectors on it so I will split the positive/red wire and attach those two the poles. I hope I’m right about all this. I’d hate to blow all the work i’ve done inside the falcon. I think I might learn how to use a multimeter today and test it all out before I wire it up.
Correct and correct. A DMM is about the single most useful tool you'll have when doing basic electronics. In this case you can use the ohm meter and measure across the switch terminals before you attach or cut anything. When the switch is open/off, it should read a very high number. When closed/on, it should read < 1 ohm.
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