Thursday, August 13, 2015

6. Putting it all together

Now that all the components are ready, it's time to put them all together. There is no way one can work with this wirey mess:

The power module, main board and button board

For this purpose I bought a nice ABS case from TME that seems to be big enough to hold eveything in. A metal case would have been better because it would have made the device more solid and it would have helped with the cooling (not there's much heat). If you find a metal case instead of plastic, go with that instead (especially if you have tools to cut the ports). Also, try to get a case that has vent holes in it to decrease the possibility of overheating.

The case as received from TME

From another angle

After measuring the front panel of the case, I used the GIMP to create a design for it then had it printed on an A4 piece of paper. This step is important from an usability point of view so make sure you arrange the ports in such way that the screen will be easy to read, the buttons easy to press with one hand and the soldering iron cord doesn't get in the way. After settling on a design the next step is to laminate the printed page so that it's nice and shiny (and not so easy to destroy):

The laminated page cut to the size of the front panel of the case

This laminated sheet will be glued to the panel, but first the ports for the screen, buttons and soldering iron conenctor need to be cut:

First the outlines were traced with a marker

Then the holes were cut in the plastic

Before glueing the face to the panel, we need to add some protection for the LCD. It's not a good idea to have it exposed directly to the exterior, especially when working with molten metal around it. For this, I used a thin piece of transparent plastic since that's all I had at the time:

Any protection is better than none at all (TM)

The protection screen was glued directly under the face mask

A better idea would be to use a piece of plexiglass since it would offer much better protection and it's easy to cut to shape. After the protection screen was installed, the face was finally glued in place:

A bit rough on the edges, but otherwise it's okay

Next up is installing the components on the front panel. Great care must be taken with the LCD installation since it's ESD and shock sensitive. Try to use some anti-ESD gloves if you have. To make things easy I soldered some pin headers to the LCD and connected the corresponding connector to a piece of ribbon wire:

One ribbon cable, 2 x 6 pin connectors and their counterparts, some heatshrink tubing and the LCD

Ready to install

Make sure to carefully think where to mount each component inside the case. If your transformer has the tendency to get warm, it should be mounted close to the vent holes and far from the power board since the electrolytic capacitors are sensitive to heat. For the same reason, it's a good idea to mount the transformer on some cardboard washers especially if you're using a plastic case so that the heads of the mounting screws don't melt through the material (sorry for the picture, I am really bad at drawing):

The washers will offer some basic protection against heat

Another thing to watch out for is mains voltage. Please double check that the cord of the device is NOT INSERTED in the mains before attaching it to the device or when working on the mains connection of the transformer! After finishing the connections, check them thoroughly then insulate them with heat shrink tubing or high quality electrical tape. Also, don't forget to connect the earth wire of the power cord to the metal bracket of the transformer, to the ESD discharge wire of the soldering iron (if it has one) and to the case (especially important if you use a metal case) to prevent electric shock in case something goes bad. A quick-reacting fuse is also required for safety and can be attached on the exterior of the case in a covered plastic holder for easy access.

After installing all the components and adding some hot glue here'n'there, my version of the soldering station looks like this:

Everything installed in the case (except for the MCU)

Note the ground connection and the connections of fuse holder in the picture (highlighted with the 2 red circles).

Well that's about it, in the next post I'll show a demo video of the station in action, so stay tuned.

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