FM modulator light only and no transmitting
- Thread starter pharaon
- Start date
Mono plays the same sound through both speakers, stereo seperates the audio to a left and right channel... so some music has lyrics or other instruments shifted to one side more than the other. It give the music more depth, and a more realistic feel.
I can do that. Sit tight and I'll get something drawn up.
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Just so you know. That was a concern with longevity of the repair product.
If you used an 78M05 to test your unit, chances are you will get the exact same result with a different supply. (like the one you are going to build)
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Right, a 78M05 is fine for testing using a power supply, but if you want to put it in a car, a transistor will be better at withstanding the surges and spikes.
It would be even better to add reverse polarity protection by inserting a UF4007 diode between the +12V from the car and the transistor's collector and the resistor, but that would mess up your nice layout because the antenna coupling capacitor should go straight to the car's +12V, which would not connet to the transistor's collector any more.
It would be even better to add reverse polarity protection by inserting a UF4007 diode between the +12V from the car and the transistor's collector and the resistor, but that would mess up your nice layout because the antenna coupling capacitor should go straight to the car's +12V, which would not connet to the transistor's collector any more.
Would putting the diode on the negative side be an acceptable solution?
will for now I'm going to build my own FM transmitting so i'll start from zero
thus I wonder if you can help me to build a good power supply circuit for the transmitting and a good FM transmitting circuit that work on line in
Well... I hate to bust your bubble but...
Building the power supply before you have an actual circuit made could very well end up requiring that you build another. These things are planned out completley before they are built.
That and. Building your own FM transmitter is not a task that will fly by in 30-minutes.
Consider if this is worth it to you. This will require more time invested in design and building your circuit (although examples can be found online, you will most likely need to tweak them for your purpose).
A new FM transmitter with a line-in can be bought extremely cheaply. I would personally rather buy a $15-$20 FM transmitter than spending any more than 2 hours on making my own.
If this is a project you want to tackle for academic reasons, we will help you learn. I personally will not be drawing a bunch of stripboard layouts to get this project done, but I will help you in getting your own drawn out so you can learn how to do this in the future with other projects.
If this project is to 'save' you some money... I hate to say it, but a DIY FM transmitter will be more expensive than buying an entry level model once you account for the time you will put into it.
Let us know
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I don't think that's a good idea. I think it would be best to keep the 0V rail at chassis voltage.
I agree with Gryd3. Any pre-built solution will be cheaper and a lot easier than building your own circuit. And it will have the features you want - reading the Flash drive and broadcasting in stereo.
I agree with you
but this is not for saving money it's for me to learn
and what I mean about build power supply I meant for the FM transmitting like the one you draw for me that one I'll build but Kris said that we can put diode to make it better and I'm nope I'm trying to learn of you guys that's why I asked Kris if he can give me a design for better power supply with the diode he is talking about so I can use it for the FM I'll build
I'll build this one and use line in rather than the mic
but I wonder if there's any enhancement you advice me to do for it
Attachments
you will find that one very unstable frequency wise
for one to be transmitting music you need one that has a PLL ( Phase Locked Loop) system
and that immediately makes the circuit much more complex.
I appreciate you want to learn to build things and that's awesome
....but you should start with circuits a bit more basic
Dave
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Here's the power supply with the diode added. This circuit has an output of about 5V. If your FM transmitter circuit needs a different voltage, you'll need to change D1 to a zener diode with a different voltage - its zener voltage should be about 0.6~0.7V higher than the output voltage you want.
Zener diodes are only available with certain nominal voltages. If you use a transmitter that's designed to run from a 9V battery, you would have to choose between a 9.1V zener and a 10V zener. I would use a 9.1V zener: http://www.digikey.com/product-detail/en/1N5239BTR/1N5239BFSCT-ND/1532769
I can't help with the rest of the circuit I'm afraid. RF is not my thing.
Zener diodes are only available with certain nominal voltages. If you use a transmitter that's designed to run from a 9V battery, you would have to choose between a 9.1V zener and a 10V zener. I would use a 9.1V zener: http://www.digikey.com/product-detail/en/1N5239BTR/1N5239BFSCT-ND/1532769
I can't help with the rest of the circuit I'm afraid. RF is not my thing.
thank a lot KrisBlueNZ
what do you mean with unstable frequency in the video it use trimmer capacitor to control the frequency..do you mean that the frequency will keep changing??you will find that one very unstable frequency wise
for one to be transmitting music you need one that has a PLL ( Phase Locked Loop) system
and that immediately makes the circuit much more complex.
I appreciate you want to learn to build things and that's awesome
but you should start with circuits a bit more basic
Dave
what is the Phase Locked Loop? what its use
how about this video
it use mp3 player to transmit it..dos it have Phase Locked Loop....
there is nothing to keep the freq stable and on the required freq, it will drift all over the place
specially with varying voltage, temperature and just by moving your hand near it
that is why they use crystal locked oscillators and associated PLL circuits to keep the freq stable
specially with varying voltage, temperature and just by moving your hand near it
that is why they use crystal locked oscillators and associated PLL circuits to keep the freq stable
I see
so do you think I can use crystal locked oscillator in the circuit in post #74
There are a TON of different circuits that can be made
If you just interested in learning, would we be able to talk you into simpler projects first?
Radio of any kind is difficult to work with, and can be made an absolute nightmare without the right tools.
You will need to be able to 'tune' your circuit, and for this, you need some way to measure the frequency of the device you make.
Some Digital Multimeters have a frequency setting, and an oscilloscope will be able to help.
Starting on something simpler will also let you focus on how the components work, as well as how to lay-out your connections and how to draw your circuits.
How would you sum up your electronics knowledge thus far?
-Are you familiar with, and comfortable with how to use a transistor?
-Are you familiar with regulated voltage compared to regulated current supplies?
-When driving an LED, you need a regulated '_______' supply.
It's pretty basic, but gets you in the door.
Ultimately it's your call on what your project will be, but I would strongly urge you to avoid wireless anything for the first project or two.
So.. do you want to track down an alternative starter project or dive into radio?
If you just interested in learning, would we be able to talk you into simpler projects first?
Radio of any kind is difficult to work with, and can be made an absolute nightmare without the right tools.
You will need to be able to 'tune' your circuit, and for this, you need some way to measure the frequency of the device you make.
Some Digital Multimeters have a frequency setting, and an oscilloscope will be able to help.
Starting on something simpler will also let you focus on how the components work, as well as how to lay-out your connections and how to draw your circuits.
How would you sum up your electronics knowledge thus far?
-Are you familiar with, and comfortable with how to use a transistor?
-Are you familiar with regulated voltage compared to regulated current supplies?
-When driving an LED, you need a regulated '_______' supply.
It's pretty basic, but gets you in the door.
Ultimately it's your call on what your project will be, but I would strongly urge you to avoid wireless anything for the first project or two.
So.. do you want to track down an alternative starter project or dive into radio?
