Computing stuff tied to the physical world

Assembling the Ether Card

In Hardware on May 30, 2010 at 00:01

(This is going to be a long post, so I’ve split it up a bit)

Here are the steps needed to assemble the Ether Card kit, starting from this PCB:

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This board is very easy to build, since it uses only through-hole parts and has relatively few components. The basic idea is to build from the flattest to the highest components. That way, when you turn the card over for soldering, you can push on it to press the component against the board.

So let’s start with the 7 resistors. Don’t mix them up, they have three different color-coded values:

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Turn over the board, don’t use too much solder, make clean solder joints, and snip the wires off when done:

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The important thing is to get the solder flowing into the plated-through holes.

Next, the ferrite bead (a small inductor which blocks high frequencies):

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Now insert the 25 MHz crystal, turn over, and solder it in:

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The crystal needs two 20 pF capacitors (the blue ones!) to function properly:

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Now add the 6 yellow decoupling capacitors (marked 104: 10 x 10^4 pf = 100,000 pF = 100 nF = 0.1 µF):

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Next in line is the 28-pin IC socket, note the notch which goes on the left:

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This one is a bit more work, you have to solder 28 pins/pads:

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Next, add the two 10 µF electrolytic capacitors. These are little “cans” with two pins sticking out on one side. Be careful, these capacitors are polarized, so you have to put them in the right way. The long lead is +, so is the square pad on the PCB. The short lead is -, it is also marked with a gray stripe on the side. The top capacitor has + pointing up, the bottom one is turned 180°, i.e. + pointing down:

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Next is the 3-pin voltage regulator. Gently bend the wires to match the triangular layout on the board, with the flat side of the package facing left, i.e. outwards. Then push it through the wholes, wiggling gently because those wires can break off near the case:

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Ok, all the main electrical components have been soldered on. Now the 3 male headers. These need to be soldered flat to the underside of the board. I normally start by adding some solder to one of the center pins:

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Then place some solder on the corresponding pad and heat them together so they join. It can be a bit tricky, but try to line up the pins and make them flush with the board:

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Don’t solder any of the other pins before the header is positioned correctly:

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You don’t need the rightmost header near the corner, strictly speaking, since there are no connections using it. I added it mostly to get some extra mechanical support.

The last step is to solder in the RJ-45 MagJack ethernet connector:

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This is what it’ll look like. Note that one (unused) pin is missing. This is ok:

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The very last step is to insert the ENC28J60 chip. You need to bend the pins slightly inwards, i.e. make them more or less parallel. Be sure to insert the chip the right way around:

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That’s it. Your Ether Card is ready to go!

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And here’s the whole assembly:

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Note that the JeeNode (or JeeNode USB, or JeeSMD) has to be plugged into the Carrier Board not just with the 4 port headers, bus also with the 2×4-pin SPI/ISP socket hooked up, so those I/O signals will reach the Ether Card. You must decide in which orientation to plug in your JeeNode – there are slots to put the headers on either side:

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Now upload the “etherNode” sketch from the EtherCard library, plug in a LAN cable, and you’ll be connected!