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i-pod speaker
i am making an i-pod speaker (3.5mm out put) as my electroics project and i was wondreing if anyone has any simple circuits that i would be able to use as the internet only shows extremly complicated ones. it also must have two intergrated circuits so i was thinking about using a pic chip and an op-amp
i am making an i-pod speaker (3.5mm out put) as my electroics project and i was wondreing if anyone has any simple circuits that i would be able to use as the internet only shows extremly complicated ones. it also must have two intergrated circuits so i was thinking about using a pic chip and an op-amp
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Just out of curiosity, is this relevant?
I ask you this because we have had a number of people come here and ask pretty much the same type of question that you asked, however I've never been certain about the level of the course, so I really don't know what to suggest.
If that document is relevant, then it appears that design is the important issue. Are you going to write a set of requirements based on the specifications of the circuit you have found? It might work, but you're doing it backwards.
If you decide the problem is that "I can't have several people listening to my iPod". Then your next step is to research the available outputs from the iPod and their levels, then determine what power is required for "comfortable listening", then go off in search of something that will transform one to the other. You may end up in the same place, but you'll probably have a more credible piece of work to hand in. Also your teacher *should* probably reject a proposal that comes with the solution but not the initial design -- but maybe standards are dropping...
My school project was an "electronics workbench" which was basically a wooden surface with an enclosure at the rear to hold a power supply, a signal generator, and amplifier and a device which allowed an audio signal to appear on a TV (a-la CRO). All of the design except the TV-CRO adapter was my own. The design brief covered ergonomic issues (such as the size of the workbench to allow easy reach of all controls), electrical safety (yes, it had 240V wiring), and various specifications that had to be met. Sure, for one power supply I pretty much knew I was going to use a 723, but because I started from specs, the final design was substantially different from the initial concept.
I guess I have high expectations for school projects.
edit: it was *many* years ago...
I ask you this because we have had a number of people come here and ask pretty much the same type of question that you asked, however I've never been certain about the level of the course, so I really don't know what to suggest.
If that document is relevant, then it appears that design is the important issue. Are you going to write a set of requirements based on the specifications of the circuit you have found? It might work, but you're doing it backwards.
If you decide the problem is that "I can't have several people listening to my iPod". Then your next step is to research the available outputs from the iPod and their levels, then determine what power is required for "comfortable listening", then go off in search of something that will transform one to the other. You may end up in the same place, but you'll probably have a more credible piece of work to hand in. Also your teacher *should* probably reject a proposal that comes with the solution but not the initial design -- but maybe standards are dropping...
My school project was an "electronics workbench" which was basically a wooden surface with an enclosure at the rear to hold a power supply, a signal generator, and amplifier and a device which allowed an audio signal to appear on a TV (a-la CRO). All of the design except the TV-CRO adapter was my own. The design brief covered ergonomic issues (such as the size of the workbench to allow easy reach of all controls), electrical safety (yes, it had 240V wiring), and various specifications that had to be met. Sure, for one power supply I pretty much knew I was going to use a 723, but because I started from specs, the final design was substantially different from the initial concept.
I guess I have high expectations for school projects.
edit: it was *many* years ago...
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Here in the UK, GCSEs are generally taken at age 16. For some students, these are the last examinations before leaving school, while others stay on to continue their studies. GCSEs are therefore taken by pupils of a wide spectrum of abilities, who will not all show the same degree of motivation.
How candidates understand what is required of them may depend on their degree of interest in the subject - are they striving to get maximum credit, or to minimise their effort? Do the questions they have asked you give a clue to this?
yes it is relevant and as part of the GCSE board I will have to do a specifications as will most of the other people who ask the same questions. however the work about working about the power for "comfortable listening" would be more than a GCSE standard or if you did do this it would put you in the high a* category but I am only looking for an a out of it. I also think that you probably have high expectations as you say for school now as no one has enough knowledge at this level to do a project of the standard that you did. I'm also sorry that it took a while for me to reply to this but I was finishing my ICT work as it has now beeing sent in for moderation.
I live in the UK too but my electronics has to be finished in may and the final exam is in may as well and I don't turn 16 until 8th may. This may not be the same for all of the school but i know all of those around my area split up the people who take electronics into two different groups, the ones who aren't predicted as high of motivated go down into BTEC engineering and there are also the other group that I am in that are predicted b, a and a* and are more motivated and have better skills.
I'm going to apologise to you here whoms. I'm not from the UK, and I had misinterpreted what a GCSE was (somehow thinking it was what your A Levels are).
Also I note that you can complete a vast number of them. My final project was done in a subject where it was one of 6 subjects -- pretty much the same as your A Levels (although it was a subject that did not count toward University admission scores).
So, I take back all (or at least most) of what I said.
There are a number of integrated circuits designed specifically for external speakers for devices like this.
I would start by looking for a device that does what you want it to, then checking the datasheet for sample circuits.
So, I went to the digikey site and searched for Audio Amplifier and then selected that I was looking for a Linear audio amplifier IC, then used the selection thing to specify through-hole first (I assume you're no planning to do surface mount work), then selevted a range of output powers (from about 150 to 750 mW), and then class AB, or B, blah blah blah, until eventually I found a reasonably small list of devices.
However I have an advantage in knowing a device that was made for this exact application I think you should look at the LM386. It's cheap, it's pretty foolproof, and most importantly, it was designed for what you have in mind.
Read here and see if you agree.
You still need to do some design work though. I would get an oscilloscope and take a look at the audio output of an iPod. What voltage level do you see? What gain will be required to get a full voltage swing from an amplifier running at 6V (as may be typical if you're running it from batteries) Can the LM387 do that?
What output power is required? If you can get a signal generator and an amplifier, connect them to a speaker and play a 1kHz sine wave. If you measure the RMS voltage across the speaker and use P = V^2/R you will get a rough indication of power (use the speaker impedance for R). What is sounds loud enough? Do the same thing with music being played (say from your ipod into the amplifier).
Can the LM386 provide that much power?
Consider that the LM386 is a single channel amplifier. You will need to build 2 of them for stereo. Do you want to do it on one PCB, or 2? Do 2 identical circuits count?
I'm sure the LM386 will be fine, but looking at the requirement for the project, if you do these tests and document them and their results, you should be well rewarded in your final mark
Also I note that you can complete a vast number of them. My final project was done in a subject where it was one of 6 subjects -- pretty much the same as your A Levels (although it was a subject that did not count toward University admission scores).
So, I take back all (or at least most) of what I said.
There are a number of integrated circuits designed specifically for external speakers for devices like this.
I would start by looking for a device that does what you want it to, then checking the datasheet for sample circuits.
So, I went to the digikey site and searched for Audio Amplifier and then selected that I was looking for a Linear audio amplifier IC, then used the selection thing to specify through-hole first (I assume you're no planning to do surface mount work), then selevted a range of output powers (from about 150 to 750 mW), and then class AB, or B, blah blah blah, until eventually I found a reasonably small list of devices.
However I have an advantage in knowing a device that was made for this exact application
I think you should look at the LM386. It's cheap, it's pretty foolproof, and most importantly, it was designed for what you have in mind.Read here and see if you agree.
You still need to do some design work though. I would get an oscilloscope and take a look at the audio output of an iPod. What voltage level do you see? What gain will be required to get a full voltage swing from an amplifier running at 6V (as may be typical if you're running it from batteries) Can the LM387 do that?
What output power is required? If you can get a signal generator and an amplifier, connect them to a speaker and play a 1kHz sine wave. If you measure the RMS voltage across the speaker and use P = V^2/R you will get a rough indication of power (use the speaker impedance for R). What is sounds loud enough? Do the same thing with music being played (say from your ipod into the amplifier).
Can the LM386 provide that much power?
Consider that the LM386 is a single channel amplifier. You will need to build 2 of them for stereo. Do you want to do it on one PCB, or 2? Do 2 identical circuits count?
I'm sure the LM386 will be fine, but looking at the requirement for the project, if you do these tests and document them and their results, you should be well rewarded in your final mark
it is ok and the problem with using the 2 integrated circuits would be an easy one to solve as I would just use a 4017b ic and then link up some L.E.D's to it so then I would have an audio and a visual output in my project and that would also give some extra marks. I think that the LM386 is a better idea than the circuit that I found before that included a pic chip and a op amp as the pic ship in the last on was able to play the music but was not loud enough so therefore had to use the op amp and this would do the job of both of them together making it a simpler circuit to be able to understand and build as well as giving me an opportunity to have a range of outputs. I will probably do all of these tests on Monday since I don't have any of the equipment at my house and as I have electronics for most of the day and I will be able to spend a reasonable amount of time doing them properly and I will also test a few of the speakers and see how much power the use to give me another idea. lastly would I be able to use a potentiometer to let the me be able to change the volume for "comfortable listening" in different environments.
All good things to do. Another wrinkle is that different speakers have different efficiencies. Larger speakers are generally better at converting the electrical energy into sound and thus they sound louder (often dramatically so).
A 4017 won't give you the sort of display you're after. Look at the LM3914/3915 (which one do you think you'll need?
A 4017 won't give you the sort of display you're after. Look at the LM3914/3915 (which one do you think you'll need?
hi,
thank you for the idea of using the LM386.
i went and did some research as you suggester and found out that the LM386 did provide enough of power and was good for "comfortable listening"
i then went out and found a simple schematic circuit diagram and i had to convert that to a PCB layout.
overall for the course work side of my GCSE i got 82 out of 90 which it 1 mark away from an a* (what i would like to get after i have done the exam aswell) so i would like to thank you for all the help you have given me
thank you for the idea of using the LM386.
i went and did some research as you suggester and found out that the LM386 did provide enough of power and was good for "comfortable listening"
i then went out and found a simple schematic circuit diagram and i had to convert that to a PCB layout.
overall for the course work side of my GCSE i got 82 out of 90 which it 1 mark away from an a* (what i would like to get after i have done the exam aswell) so i would like to thank you for all the help you have given me
Hi,
I have a few questions about this. what did you use to amplify the input and do u still have the schematic?
Nik
I have a few questions about this. what did you use to amplify the input and do u still have the schematic?
Nik
Its just i cant find any simple schematics on the internet or with roughly the correct voltage that i need (9 volts)
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