No electronics project of mine ever ends without me rerouting and resoldering at least two connections.

Why?
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I haven't got a clue, but I can tell you what I did.
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(Somewhat) apropos yesterday's article on tinkering: I wanted a simple setup to mount my Treo phone/pda in the car. None of the kludges for sale impressed me favourably, all being expensive/clunky/both or worse.

Being the Dismantler and Recycler Of Crap that I am, I have a few dead hard disks sitting around. Dead hard disk = two large and strong magnets, iff you manage to get them off their backing without breaking the brittle material. Sometimes I do manage, sometimes I don't.

So here's my ghetto mount: a fat magnet in heatshrink tubing, embedded in the back of a slab of coreflute which is stickytaped to the car dash. The Treo-side consists of a bit of thin sheet metal (was once part of a floppy drive housing) taped to the back of the treo with super-thin packing tape.

The hard disk magnet is easily strong enough to work through one layer of heatshrink, coreflute, the silicon glove and the packing tape. With the packing tape no irreversible mods to the Treo are necessary.

Simple, neat and zero-cost. I like that.

It's Conny's laptop and I'll paint if she wants that.

Actually, she does, and not surprisingly, I did. She wanted a skull and crossbones design and who am I to object to that Sound Sensible Choice :-)

I found a tiny image on the web and used that as an inspiration to come up with this design. Then I reused an old conference presentation slide and cut that for a mask, and went shopping for paint: fluoro pink. The mask I fixed to the lapdog lid with spray glue (sprayed onto the mask, of course), and then I rattlecan-sprayed four layers: plastic primer, a thin coat of silver as a lightening base and two layers of pink. Removed the mask, cleaned the glue residue off and neatened some of the spots where I had been too generous with the paint (raised edges). The stupid pink paint decided not to be very fluorescent (even with the silver base), but pink it is. Another coat of gloss enamel for the whole lid is forthcoming, but Conny is pleased with the result - and so am I.

I just saw a really interesting article, titled reflections on tinkering. Recommended.

The object of my repair efforts this time: a Coleman Instant Hot Water system for camping. The product is nice, the company is lousy and unwilling to sell any spare parts; but that kind of plot does not work with me.
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I dislike throwing away repairable things. Like this old, very cheap but quite good knife (originally from Ikea): after more than a decade of daily use and the associated dunkings, the wooden handle had finally rotted away and split.

So I made a new grip: reused some wood reclaimed from a door frame, shaped it with my router, glued-and-screwed the grip halves on, sanded and lacquered the thing multiple times.

Why? Because I can, because it is fun to (re)make things and because a well-made thing gives me satisfaction.

My Wheely King RC toy was a tad fast for crawling over obstacles and also lacked torque and endurance with the stock motor and batteries. Simple fix: I cooked up a cheap brushless motor setup.

Ingredients:

• one cheap Chinese 2830 outrunner (850KV, 58g, 3.17mm shaft): $20 with shipping
• one fairly cheap Chinese/German ESC (speed controller) for brushless motors, $35 plus $15 shipping
• smaller pinion gears, 12, 13, 14, 16 and 17 teeth: $20 plus $10 postage
• some time for filing down the motor mount: dusty but free

Install the 14 tooth pinion. Mix and stir well. Season with absolutely incomprehensible Chinglish instructions for the ESC. Simmer on "Medium Angry" for a week. Find the German partner company who's responsible for the design of the ESC, and who has a manual in Real English. Turn off the heat, install, enjoy the slooooow speed at full blast. Up the pinion teeth, to 16. Reinstall, enjoy both the torque and fast-walking speed on full throttle. Mounting the brushless dwarf was interesting, because it doesn't have the same screw pattern as the big 540-size original motor. It comes with a converter plate but using that the shaft is too short. So I made do with the smaller screw spacing. I simply filed away a fair bit of the motor mounting plate and then used a drilled steel washer as counter-piece for fastening the motor.

Getting the ESC to stop beeping and start working was almost as horrible as having to learn vi without a clue and a manual (ie. it beeps a lot but doesn't work, no matter what you do). Extremely frustrating. The thing being a very no-name non-brand, I even cut off the heatshrink to have a peek at the circuit board looking for manufacturer clues, but to no avail. Eventually and only because of a few really odd, happy circumstances I finally found out that it's one of these and got a working manual. Wohee, this actually works! I glued on an old heatsink block to the ESC's metal back plate and then closed it up again with transparent heatshrink tube. Looks neater than the original.

Overall the result is very pleasant. Torque is way up, this ESC has a proper brake (which the original didn't have) and with the tiny brushless motor (a powerhouse despite weighing only a measly 58g) I get very nice long run times even with the old original nicad battery. The reduced weight up top helps too.

As mentioned earlier and before I have a Wheely King rc toy. Me being me, that WK is nowhere near stock and I often delight in tinkering with it to make it work better or more fun or whatever.
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Not entirely unlike a Kaplan turbine, my mini-turbine is used in a high-flow, low-head(room) scenario. Only in reverse, sort-of. Confused? Perfect, mission accomplished :-)
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Conny likes to fall asleep with some light on. I dislike having to wait until she's gone late at night, just to switch off her bedside light. I dislike having an energy-wasting halogene 25W burning all night long even more, not to mention the temperature problems with the transformer base buried in stuffed animals.

The solution: teach her something! So we repurposed an old broken desk lamp carcass, I taught her how to solder, programmed a 12f629 PIC and we combined the above with sufficiently many white LEDs and some recycled laptop Li-Ion cells into an auto-off bed light: Press the button when off, and you get 18 min of light. Press the button when the light is on, and the light goes off. Simple, neat, efficient. As a bonus the lamp body is black, Just Like It Should Be.

The circuit is trivially simple, the diagram follows and the PIC code (also boringly simple) is here (plus the auxiliary delay library).

The diagram is not complete in two particulars: I used a 4.5mm plug with a builtin bypass switch to isolate the battery when charging (don't want to blow the LEDs and/or PIC when my intelligent charger feeds the LiIon), and I repurposed the original lamp switch as an extra "general disconnect". BSTS.

Great care should be taken to avoid shorting or annoying the three 2000+mAh cells in any way - unless you like to play with fire extinguishers.

Conny did all the soldering apart from one or two small fixes and the LED interconnections. Well done.

I enjoy technical challenges...if and when I succeed eventually. This posting may be a technical challenge for you, but watch me not care. Some of you may appreciate the information and that's good enough for me. So, if you're interested in homegrown MP3 music boxes, Linux on Netvistas, PIC microprocessors, RS-232, infrared remote controls, and what an obtuse idiot I occasionally am, read on!

(As always I also hand out the involved source code, which might come handy if you want to build something similar.)
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This was actually quite fun to build, a quickly gratifying small job: how do you drive an LED from very little voltage (as in, a single 1.5V cell)? You can't do it directly because leds need more voltage (at least 1.6V for reds, above 3.0V for many/most whites).

So you need some booster circuit. Clive has a nice set of instructions for making what he calls a "Joule Thief", a simple inverter with three parts only: a centre-tapped inductor, a resistor and a transistor (He also has articles on other Must-Have Cool Things, like how to make a USB-powered turd).

For the ham-fisted among us, these guys show how to build the same setup with larger-sized parts.

I had a few minutes of nothing better to do this arvo, and built three variants with a fat 10mm white led: one hand-wound largish coil (2cm dia), one salvaged coil of similar size, and one smaller hand-wound one (0.9cm dia) with which the circuit wouldn't light up continuously.

For the adventurous, Dick Cappel has another set of really nice pages on similar projects, like the Rusty Nail LED inverter.

Daylight is fine, but darkness isn't to be frowned at. If you have LEDs, that is.
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Rob gave me a 1GB clonepod. Its Chinese designers made a number of...questionable design decisions, and as a result the player was somewhat broken when I got it.
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A few months ago, I made a simple PIC-based POV toy for my daughter. Here are some building notes, photos and code of course.
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Silastic RTV sealant is very useful, even if a third of the tube has already vulcanized...
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Having a 4 channel oscilloscope makes tinkering so much easier. Now I can look at four incomprehensible and unexplainable voltages at the same time!
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...to hear how my friend rob is spending a lot of time in the gym. My character is already fucked, so why waste time in the gym? It's spent way more productively with soldering iron in one hand and a datasheet printout in the other ;-)

Latest example: I talked to rob earlier this evening (about 3.5hrs ago), and he asked me how hard it would be to make a Hardcore Gym Timer, so that he can keep his "8 second blast/12 second slow" training regime precisely.
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"Innsbruck, Ich muß Dich lassen"...viel schlimmere Barock-musi gibts nicht. Ein guter Grund, das Gedudel als Türglocken-Melodei zu verwurschten. Weil es soll ja nicht gut und wohlig klingen, sondern laut und nervig damit a) ich aufkreuch und zur Tür gehe und b) die Wartenden sich möglichst gleich ohne meine Mithilfe dazu entscheiden daß sie sich schleichen. Weil mei home is mei kastl, da sind nur wenige besondere Leute willkommen. In diesem Sinne also eine perfekte Wahl. Wie ich das verbrochen hab, erzähl ich weiter unten.
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Somehow I don't think I'll run out of caps anytime soon. As I've been tinkering a little bit with electronics and microcontrollers recently, some more components were required. I dislike wasting money. And I like bargains.

Somebody sold off his stuff by the kilo, after retiring from an electronics repair career. All bandoleered, also mostly labelled and well mixed: a few strips of transistors and filters/ceramic resonators, resistors, a pile of chokes/inductors, some tantalums, a pile of ceramic caps, a big pile of film caps and a bloody huge pile of electrolytics. I said well mixed: all common values well represented. Ah yes, and more fuse holders than I'll ever need.

4.7kg of gear, for a whopping total of AU$80. I'm pretty pleased. But the sorting is a pain.

I've got a new toy: a Tektronix 2246 ModA, for about $500 (incl. shipping from the UK). It's really nice (100MHz, 4 channels, analog but microcontrollered, hence nice measurement and cursor features).

Current project: making a very obnoxious and loud doorbell with a PIC. I came up with the necessary microsecond-precision delay routines and the remaining frequency generation stuff, and a bit of perl took care of eating a MIDI file and barfing out suitable frequency and duration information in PIC assembler.

The last insanely horrible tune I've been trialling: "Innsbruck, ich muß dich lassen". Sounds perfectly ghastly when a cheap piezo is squarewave-squealing its guts out. I'm also thinking about using "Tirol isch lei oans" just to remind me why I'm here and not there.

Here's a pic of the latest test setup: I'm currently learning how to use an inductor to boost voltages (and how a common collector amplifier works). Messy but fun.

...cupboard doors into desks, IBM Thinclients into music boxes and all politicians everywhere into dead politicians. I'm all for it, and I did my part for the doors and the music player. (And just for the bloody record, let's get rid of all the governments, too. Yay for Anarchy! I'm in a bad mood today, as you can surely tell.)
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Here's some recent projects/happenings. For my new RC plane I needed reasonable charging facilities, because most trickle chargers like the one I got with the RC gear are trash. So after some thinking about building my own charge controller (not too tricky but time-consuming) I bit the bullet and bought this SJ Propo Swallow Advance charger: a very nice bit of equipment, charges pretty much anything from Lead-Acid to Li-Po intelligently, and with nice options. $90, so not exactly breaking the bank.

But the Swallow is DC only, 11-15V, good for taking with you in the car, bad for at home. I hate wallwarts. So I need: DC, preferrably 12V at 3-5A. But I have: loads of lousy underpowered wallwarts (bad) and loads of old garbage (good). Because the old garbage contains the innards of a few Sun SCSI enclosures, some of which came with brilliant fanless Sony-made switching PSUs. APS-28: old, silent, solid, juicy and saucy :-)

Time for the tinker: it simply took a few galvanised nails, some foam and a bit of soldering to convert the Molex outlets to posts for crocodile clamps. (There is extra insulation behind the foam, but the sparkies wouldn't be too happy with the design. Screw 'em!)

That PSU now also replaces three wallwarts, which makes me really happy. I fabricated some custom charging leads from scrap (old wires, some computer connectors, crocodile clamps from rotten test leads etc.) next: one 12V lead for the Yaesu VX5R which has its own charge controller (Li-Ion) and a tiny plug, one 12V fat plug for the CDMA phone's charger-stand (with its own controller).

The fat plug also works with the cordless drill, now and only after I gutted the drill charger stand: first I connected the Swallow to that, but the stand actually contains a few resistors for trickle charging. The Swallow blasted a few Amps at about 19V across that, the resistor got a tiny little bit hot, the stand plastic started growing surrealistic in shape and I quickly stopped things before the Magic Smoke got out. Now: gutless stand, brains in the charger. Me happy.

Another recent successful tinkerproject was modding Guntis' radio: he wanted a remote PTT switch to connect to his small speaker-mike sitting on his shoulder, just like the setup I've used for the last two years. (My new in-helmet setup was tested on Sunday and works superbly.) So I hunted up parts, traced the wiring in his speakermike and Simply Dit It. First I rewired the speakermike to activate on the PTT switch, and then I built a new remote PTT switch from scratch.

Here's the switch I made for him: 100% recycled components! :-)

The switch is a leftover from a dead computer mouse that I desoldered, the cable with conveniently moulded-on mono plug comes from a first-crap-then-defunct $50 "stereo system", the button (for improved tactile feedback with gloves) is from the sewing kit my great-aunt left me, and the velcro was a leftover from some other project. Even the idea for the switch is recycled: this guy had it first :-) (Ok, solder, superglue and shrinktube were new. Sue me.)

And the next projects are already on the horizon: exploring the wonderful world of PIC microcontrollers. These things are cool! (I recently spent about $250 on a better multimeter and a bunch of chips, and may soon spend another up-to-$800 on an oscilloscope. Learning electronics is fun, but getting a reasonable set of tools is not -- for a money-concious person like me.) Here's my first pic circuit: it toggles the led state on every switch activation, debounced in software. Looks like nothing, better stuff to follow soon because I've got shitloads of wacky ideas that I want to implement...