I had some time this weekend to assemble my Daisy MP3 player kit. This amounted to 3 or 4 hours of soldering everything together, making a few mistakes, and working around some minor problems. Now I’m listening to the Make podcast on my first open source MP3 player, and I’m happy to say my feeble soldering skills got me by. If you’re a little new to this stuff and you’ve been wondering how to put this bag of parts together, don’t sweat it. I’ll take you through some of the tricky spots and you can share your experiences and questions in the comments.What You Should Have Before Starting
Soldering Iron: There are great ones. There are crappy ones. I think mine doubles as a wood burner. You’ll probably be a happier person if you get the best one you can afford, but if you’ve got something with a relatively pointy tip and it gets hot enough to melt solder then you can probably make it work. Beware that the cheap irons tend to get really hot. You can counter this by constantly cleaning it on a wet sponge, keeping a layer of fresh solder on the tip, and turning it off when you aren’t using it for a few seconds. Start using it right away once it’s warmed up enough to melt the solder you are using. You don’t want it to heat up too much or you risk overheating a connection and delaminating a trace from the board.
Solder: Get the thinnest rosin core solder you can find. It should be thinner than the width of the pins you are working with.
Solder Sucker: This is a bulb with a narrow tip. You can use this to suck out excess solder from tight places. For instance, if you’ve accidentally soldered over a hole, just heat the hole from one side with the iron, and suck on the other side with the bulb. It’s pretty easy once you get the hang of it.
Solder Wick: This is a braided copper wire that absorbs heated solder like magic. Good for cleaning up messes.
Side Snips: For cutting off the excess leads, cutting things to size, etc.
Basic tools: You’ll probably want a needle-nose pliers or a pair of tweezers to hold and position hot things. Some little clamps can come in handy as well if you feel like you’re running out of hands.
Soldering The Decoder Chip
The first step is the hardest, and the VS1011 is why. This chip is responsible for decoding your MP3 files, converting digital signal to an analog waveform, and amplifying it for the headphone output. It does all of this in a package as small as the tip of your pinky finger.
As great as this IC is, you’re going to have to solder it directly to the board, and it’s surface mounted… not to mention the tight spacing on the leads. You’ll want to take your time with this one, but it’s doable. Start by putting a very tiny solder bead on one of the corner pads. Then position the chip carefully and heat that corner pin to fasten it to the corner pad. Once it’s secure, solder down another corner and make sure everything is lined up perfectly.
When it’s secured and aligned correctly, solder down all the rest of the pins. Don’t worry about solder spanning between pins. We can clean that up later. Just focus on making sure that solder has flowed correctly and fused each pin to its pad.
You’ll probably end up with a big mess of excess solder. You can use the iron to melt the excess and, using surface tension, pull the excess solder around. Try and collect it into a big pool. Then you can lay a clean strip of solder wick over the lump, heat it with the iron, and the excess will flow into the wick. You may have to do this several times, but eventually there will be so little solder left on the pins that the surface tension will keep the solder from spanning multiple pins.
I’m not sure if there’s a better way to do this, but it worked okay for me. It just requires a little patience and a little trust that it will turn out okay. I made a quick movie so you can get an idea for how much of a mess you can make and still have things work out for you:
Once you have the decoder chip mastered, you’ll find the SD socket, the audio jack, and everything else to be pretty straightforward. Pay special attention to the tabs on the audio plug and SD socket. These serve to hold the components in place when you’re jamming stuff into them, so you want to focus on a good physical bond when you are soldering.
The LEDs in the kits are really tiny. If there’s any polarity marking (flat side) on the casing, I can’t see it. Just don’t trim the leads at all before you have soldered them in. The side with the shorter lead should match up with the flat side in the diagram on the board.
The 10uF capacitor doesn’t fit particularly well between the 40 pin socket and the resistor network. You just have to lean the resistor network over a little to make room for the capacitor.
Pay attention to the order of assembly in the instructions. It’ll save you a lot of hassle, as it gets the hard-to-manage pieces done before other parts start getting in the way.
FAT32 And Nothing Else
When you first turn the Daisy MP3 player on, both LEDs should light up. If you’ve got an SD card in with an MP3 on it and nothing is happening, it’s probably because the card isn’t formatted FAT32. I was testing with a smaller, 64MB SD card, and it was formatted FAT16 by default. I was unable to format it as FAT32 using the OS X disc utility, but if you reformat your card on a pc (with a USB SD card adapter), you’ll be able to read and write to it from either OS just fine.
To format your card with a FAT32 filesystem (assuming your card shows up as drive E:), type the following at the DOS command prompt:
format e: /FS:FAT32
Then copy an MP3 over and give it another shot. The red light should flicker and you should hear sound now.
Where To Go From Here
Here are just a few ideas for making the best use of your Daisy:
- Make a slick looking case to show up your iPod.
- Add audio output to a home-brew clock.
- Use the addressable track mode to give your robot a voice (think R2D2).
- Add an IR receiver to enable advanced remote whoopee-cusion technology.
Have some other good ideas? Please share ‘em in the comments!