{"id":1516,"date":"2018-02-20T17:24:38","date_gmt":"2018-02-20T15:24:38","guid":{"rendered":"http:\/\/borkedcode.com\/wp\/?p=1516"},"modified":"2018-02-20T17:24:38","modified_gmt":"2018-02-20T15:24:38","slug":"the-uss-enterprise-refit-from-star-trek-the-motion-picture-16","status":"publish","type":"post","link":"https:\/\/borkedcode.com\/wp\/?p=1516","title":{"rendered":"The USS Enterprise (Refit) from Star Trek: The Motion Picture"},"content":{"rendered":"

Build Log: \u00a0Part 16<\/h1>\n

Well, hi!<\/p>\n

First off, I feel an apology is necessary here \u2013 I haven\u2019t updated my log in a LONG time, and I should have.\u00a0 I\u2019m sorry.\u00a0 Since last we spoke, I\u2019ve had a move across the country to Munich and started a new job with a cool biotech firm, and that\u2019s been occupying a big chunk of my time.\u00a0 I haven\u2019t had the kind of space or free time to do the Enterprise justice, so I have been doing some Delphi coding and a couple of ocean-going ship models in the limited environment I\u2019ve had.<\/p>\n

However, I have a proper man-cave now, and I\u2019ve been able to make some progress, so it\u2019s time for an update!<\/p>\n

In trials with that little Chinese MP3 player, I discovered that the power output from a PC USB port is anything but steady, and this resulted in the player re-setting itself at random intervals.\u00a0 This had a really awful effect on my attempts to code a solution for the Big E, and I eventually scrapped it.\u00a0 I didn\u2019t find out about the voltage problem until well after I\u2019d soldered together a very nice transistor setup on that board I showed you, and while the player was having fits being plugged into my laptop, I was left thinking I\u2019d screwed something up in my soldering.\u00a0 As it turns out, I had everything right, but the player just wasn\u2019t up to the job.<\/p>\n

So let\u2019s talk about that player for a bit \u2013 given its sensitivity to voltage changes, it really isn\u2019t a good choice for a model that has more than one sound.\u00a0 If you\u2019ve got just one sound or some background noise, it\u2019s probably a solid play.\u00a0 But for what I have in mind, it just won\u2019t cut the mustard.<\/p>\n

Instead, I went looking for, and retrieved, several different MP3 options.\u00a0 My favorite so far, and one that does<\/em> work for this job, is this:<\/p>\n

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All the power of an MP3 player in about 1.5cm square.<\/p><\/div>\n

It takes a micro-SD card, just like these little players, and is only just barely larger than one.\u00a0 It\u2019s called a \u201cDFPlayer Mini\u201d, and you can get them dirt-cheap on eBay.\u00a0 Reference materials are widely available on the web, and they\u2019re very easy to control from an Arduino.<\/p>\n

Before I start digging into the Arduino code, I want to go into the soldering and setup of a PCB board with you first (skip ahead if this isn\u2019t of interest to you).<\/p>\n

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I\u2019m not a professional electrician, so if you have access to one, take their advice ahead of mine.\u00a0 I\u2019ve found this set of methods to be very useful, and feel it\u2019s my duty to share.<\/p>\n

Get the right size PCB board first \u2013 PCB means \u201cprinted circuit board\u201d, by the way, it\u2019s not some magic acronym or anything.\u00a0 You want to accommodate not only your parts, but your fingers too. Try to imagine where it\u2019s going to be mounted (in the model? in the base?) and what kind of height you\u2019ll have available.<\/p>\n

I\u2019ll probably design my base with an inch or two of height in it, and since this model is so huge there will probably be some very big empty spaces in the base\u2026so that\u2019s where I\u2019ll stick most of my controlling systems.\u00a0 The TrekModeler board will go in the secondary hull, so I won\u2019t have a kajillion wires going up-and-down the post.<\/p>\n

You\u2019re going to need wire \u2013 at least two different colors of insulated wire, and preferably one more spool of non-insulated.\u00a0 (Non-insulated tends to be a little stiffer, too, which makes it useful for creating false \u2018legs\u2019 for soft wires during your breadboard testing.)\u00a0 These shouldn\u2019t cost you a whole lot, and can be had from Radio Shack, Conrad, or bought online.\u00a0 Leftover speaker wire can work, but that can be a bit thick for this purpose, and hard to work with.<\/p>\n

Some needle-nose pliers are also going to come in handy, although you could probably use a wooden chop-stick from takeout Chinese to get this job done too.\u00a0 Wire snips are a big help (kitchen scissors work, but are kinda large and you might end up blunting them).<\/p>\n

Many electrical parts require properly-metered resistors to go with them, and of course longer wires from the board to reach your lights and so on.\u00a0 Although it is possible to mount them on a PCB and thread all the \u201cfeet\u201d together, I find that using little \u2018horseshoes\u2019 of uninsulated wire to connect the parts makes things slightly clearer when looking at the board.\u00a0 For some reason, I also find it easier to get my parts to sit more cleanly when using horseshoes.<\/p>\n

To make a horseshoe, just take some uninsulated wire and wrap it around one point of your needlenose pliers (or a chop-stick) and snip off the excess.\u00a0 Using those needlenose pliers, you can then grip the horseshoe by its middle and insert the legs into the holes on the PCB you want them in.<\/p>\n

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Grab the wire with pliers, end flush to one side…<\/p><\/div>\n

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Gripping the wire tight, roll the pliers so the wire folds flush against them at about the right thickness to match the holes on your PCB…<\/p><\/div>\n

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This makes a little “hook”.<\/p><\/div>\n

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Snip off to have even legs.<\/p><\/div>\n

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It’s easy to make quite a few in advance, so they’re ready when you need them.<\/p><\/div>\n

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When used, they make a nice clean look.<\/p><\/div>\n

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When soldering, a key rule to remember is \u201cless is more\u201d.\u00a0 You only want to use just enough solder to fill the hole in the PCB and cement the legs of the parts inside it.<\/p>\n

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Good solder looks like this.<\/p><\/div>\n

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You don\u2019t want a great big glob on the board, and you absolutely don\u2019t want spill-over to connect other parts of the board (these are called \u201cshorts\u201d \u2013 they\u2019re responsible for the term \u201cshort circuit\u201d, which is generally an undesirable connection that can potentially damage your components).<\/p>\n

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Bad solder, on the other hand, can look like that.<\/p><\/div>\n

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I went into a little detail in my last installment about how the functions of the program are going to work\u2026but after looking it over I\u2019m going to have to be more detailed than that in order to ensure I don\u2019t bork something up completely.\u00a0 It\u2019s going to be a rather extensive wiring setup, and I\u2019ll use one other 3rd<\/sup>-party item, a lighting board from TrekModeler (at least, I think I\u2019m going to use that \u2013 I haven\u2019t run current through it yet, so at this point I\u2019m assuming that it will do the job I want) to handle the lightup and power-down.<\/p>\n

Some of this may get a little tedious, but you really have to be tedious when you\u2019re designing an embedded software program with electronics \u2013 once it\u2019s in, you aren\u2019t going to get much chance to change it.\u00a0 (Where I position the controller will make this easier, but let\u2019s assume for the sake of argument that you aren\u2019t going to have that option.)<\/p>\n

Here are the main routines as I envision them:<\/p>\n