Posted January 15, 201213 yr I want to give my brother a unique gift for his birthday. I decided that I am going to make him a MP3 radio. It will not produce ear shattering audiophile output but it should sound good for what it is. The design of this radio will make it useful for near field listening such as a computer desk or small room book shelf. There will be four different audio input methods:MP3 decoder with memory card and USB drive readerBluetooth input capability3.5mm audio input jack inputThe unit will have three identical enclosures. The center enclosure for the electronics and two enclosures for the left and right speaker. I am using a Dayton audio 15x2 amplifier and Tang Band 3" full range drivers. I will not be using any filters on the drivers. I will be porting the speaker enclosures so a baffle step filter should not be needed. Someday when I have the dough for a proper microphone and software I will be able to design filtering networks.My MP3 decoder is on backorder. When I have it I will post pics.I have not started assembly this yet. I am still piecing everything together and figuring it out.I am using an outboard power supply. The Bluetooth module and MP3 decoder need 5V. I will be building a 5V regulator.I placed a penny in the pics so you can see how small this guy is
January 16, 201213 yr Author Sounds neat. Way more technical than anything ill ever do.Actually it isn't that technical. I am just wiring up a bunch of electronic components.It probably will not be the best sounding radio but it will be unique!
January 21, 201213 yr Author Small update:*Sorry for the shitty pics.*I used a Radio Shack breadboard to layout a simple 5V regulator circuit built around a LM7805. LM7805 diagramHere is the basic circuit.Board designSimple video of how the circuit works. For some reason the video quality became very poor when uploading it Next up is to transfer the circuit to a PCB(printed circuit board).
January 27, 201213 yr Looks nice, should be pretty sweet when it's all done.I read you want to get a mic so you can make networks, can't you design and test them out with software?
January 27, 201213 yr Author Looks nice, should be pretty sweet when it's all done.I read you want to get a mic so you can make networks, can't you design and test them out with software?Yes you can, primitively. Play incremental test tones and use a spreadsheet to record the SPL. The data that was collect will represent any peaks and dips in the FR.
January 29, 201213 yr Author Here is a screenshot of the PCB layout that I designed, very basic. I need to print this out and transfer it to a single sided copper board to be etched.
February 6, 201213 yr I love tinkering around with stuff like this. Cool project, did you find an instruction manual for this or is your design?
February 7, 201213 yr Author I love tinkering around with stuff like this. Cool project, did you find an instruction manual for this or is your design?No instruction manual or how to. There are similar projects around the net but nothing exactly like this.This is a cool build, I can't wait to see the finished productI just got my copper boards in the mail. After I make the PCB I can continue. I have until April to finish this so no rush.
February 12, 201213 yr Author Update.I finally had a minute to mess around with this.I revised my circuit layout with thicker traces and larger solder through holes.I printed my layout on Press-n-Peel. I trimmed and piece of copper PCB board to size.I iron on the Press-n-Peel. Here is what is left on the copper board.I etched the remaining copper off the board.After cleaning off the toner, copper traces remain!Up next is to drill the through holes and solder the components. Edited February 12, 201213 yr by edouble101
February 12, 201213 yr Author Honestly...that is cool as hell.I'd probably end up like Thanks man I had imagined the copper traces be more fine lined and precise. But I guess for a first time PCB construction it isn't too bad. Good enough for this atleast. Edited February 12, 201213 yr by edouble101
February 12, 201213 yr Edub, I know you got a while before you give it away, but I am loving this build and dying to see how it all comes together in the end. Are you gonna make some sort of housing for everything? Like a hobby box,etc?
February 12, 201213 yr Author Edub, I know you got a while before you give it away, but I am loving this build and dying to see how it all comes together in the end. Are you gonna make some sort of housing for everything? Like a hobby box,etc?I will be fabricating three enclosures. One for each speaker and one for the electronics. The enclosures will be a mostly 3/4" oak with a dark stain. I also have a couple unique materials/components I will be using
February 13, 201213 yr Author I have the PCB done. Onto bigger and better things!Drilling the through holesAll soldered.Penny to show size. Edited February 13, 201213 yr by edouble101
February 17, 201213 yr Author crazy tiny!!!Yep.I drew up the enclosure plans last night. Possibly next week I will start on them. Edited February 17, 201213 yr by edouble101
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