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Radio Controlled LEDS?

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Hey Blue,

I may have explained it poorly, but the idea was to have a limited range on the RF signal, and then just detect signal strength. I'm not exactly sure how that is done yet, but I think the idea was that the receiver would detect the incoming signal and once it trips a "threshold" then the MCU sees that it has enough strength and the lights begin to turn on.

The thing I am trying to figure out is whether the MCU is sending out "Data" letting the other MCU know that two other devices are in range.

Someone on another page suggested just having two receivers in each device hooked up in series so each have to have a strong signal in order to "trip the switch". This is an interesting solution as it doesn't involve any MCU's, but I think I need the MCU's there anyway to control the lights.

So basically, I'm trying to get a straight answer as to what is the best solution, which schematic to begin with, and if the MCU's are detecting frequency, ID's, or something.
 
The thing I am trying to figure out is whether the MCU is sending out "Data" letting the other MCU know that two other devices are in range.

It depends on what you decide :) ...

1. if you go with 3 different frequencies (light or RF does not matter) that will not "mix" then each device should have 2 receivers (one on each freq as the other two devices) .. then when both receivers are "triggered" you do what you wanted to do (flash lights)

2. other way is "do it on single freq" but then you need all devices to emit ID, and you need devices to decode received ID in order to know if one or two devices are near

if you go with 1, it is bit more "parts" meaning "bit more power consumption" but it is logically simple. If you go with 2, then you have more logic to implement (you cannot just send data all the time, you need to listen and send data only when the "air is clear", you have to decode the data ..)

in general, [1] uses more power, has more "parts" but it is simpler to make and probably can be done uC free ... the [2] solution requires uC and some sophisticated programming but it should consume less power (as it will have only one receiver and not two)
 
have a look at the TI CC1110, 1111 range. These have a single cycle 8051 and data transciever with +10dBm(enough for this project) for a few dollars each. Very low number of external components required. TI als include simple networking software.
 
arhi,

in general, [1] uses more power, has more "parts" but it is simpler to make and probably can be done uC free ... the [2] solution requires uC and some sophisticated programming but it should consume less power (as it will have only one receiver and not two)

Good call! I wonder though, this is basically assuming that there are no other RF signals in the area. So if I have an only RF (uV) free system, there may be issue with interference no?

Using an ID, might make things a tad more reliable if there are conflicting RF signals since all that would have to be done is to tune all the devices to a free frequency instead of possibly three new frequencies.

As well, slightly lower power consumption might be a good thing as the LED's still have to go as well....so the more power I can commit to the LED's, the better, but you're right it that it'll take some more programming.

Tough call...perhaps I'll start simple to see if it even works, and then go from there.

(on a related note)

Would putting resistors on an antenna limit the power and decrease the distance? How does one decrease the distance of an RF signal?

Super_voip, thanks, I'll look into those for sure!
 
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Could someone please check my breadboard circuit? I can't seem to figure out if it's working or not. I can't find it anywhere on my FM dial.

**broken link removed**

Thanks,

Jeff
 
You can't build VHF circuitry on a breadboard, and certainly not widely spread out like that - it's essential that it's small, compact, and correctly designed, and NOT on a breadboard.
 
Awww...really?

Dammit...that's like $40 down the tubes.

Could you perhaps post some links for what I need in this. I have spent like $200 in stuff and I'm not getting anywhere. If someone could write me a definite list of what I need that would be awesome!

Also, is there something better I could use for C5? The plan calls for a 3-18pf Adjustable Cap, but no one in town has that. I had to go with a 5.2pf -30pf Trimmer Cap...

Here is the link. FM Transmitter
 
I think you guys are talking about this one?

**broken link removed**

I have a few questions...as always :D

- Is there a parts list for this anywhere with alternatives for some of the more "rare" parts?

- What is that silver wire on the photo, is that just normal wire? What kind of wire would I get

- What gauge is that copper wire?

- What is that part (LM2931a 5.0)?

- Could I just take the mic right off? Or does it need a mic to send a signal (I don't need a mic in my design, just a signal that a receiver can pick up)

- Would my 5.2pf - 30pf Trimmer Cap work for C6/C13?

- How big is that thing?

Thanks!
 
Wrong forum, I don't think you can view attachments unless you're logged on so this might not make any sense to a non-Electronics Lab member.

He's posted exactly the same thing over here.
https://www.electro-tech-online.com/threads/some-more-simple-fm-transmitters.12489/
fm_transmitter_mod4_pic_schem_212-gif.7058

The LM2931A5.0 is a low droput voltage regulator.

The silver wire is just tinned copper wire.

I don't know what gauge the copper wire is, it looks like 0.5 to 0.75mm² to me. It also needs to be enameled so the turns don't short circuit each other.

You can omit the microphone and all parts left from R6 and C5, if you just want to broadcast a continious wave signal.
 
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Ha, I'm on like 5 forums....so I'm confused.

I think we're talking on two different forums, and that's whats getting me confused.

I have some 28 MAG 1.4lb. wire...

Thats awesome about the mic...thanks for that info. I really don't need a Mic in the end, but it's good to know I can perhaps use it to start and test, but then rebuild without one.
 
What I would like to do is, have 3 separate LED lights which would only light up if all three are close to each other (within 2 or less feet), yet when you take all three outside of that radius, they turn off.

A very long thread: but has anyone asked why you want to do this? It may help to get an idea from outside the box.
 
Ha, I'm on like 5 forums....so I'm confused.
I don't know about the other forums you post at but this is the best one I've seen.

Electronics Lab isn't very good because half the projects don't work and the moderator is a bully.
 
A very long thread: but has anyone asked why you want to do this? It may help to get an idea from outside the box.

Nobody had to; he explained it all quite early in this thread. And 6 pages isn't a terribly long thread. ;)


Torben
 
You are dreaming.
The system is much too complicated for your first project. It is many different circuits put together and you don't seem to know about the problems any of them.
 
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