Well, I’ve officially joined the DIY electronics community. Last week, I attended my first Maker Faire. It was my city’s first ever, and I was determined to take one of my projects as a booth participant. Nothing like a deadline to get my hind quarters into gear and (kind of) finish a project!
*** The following is a “bitter old engineer” rant. You’ve been warned.
At this ripe old age, I have come to value most the quality of a toolchain. I’ll go a step further and say that the coherency and consistency of the umbrella that toolchain inhabits is a most prized quality. And what spurred this revelation? Why the obtuse declaration?
I have seen the other side, brothers and sisters. I have felt the greener grass on the knoll of Arduino, and I’m here to tell you something: it ain’t that green.
My (albeit, limited) experience to date in hacker-friendly Arduino land has been lackluster. It reminds me of another favorite rant of mine: Linux. There are some striking similarities between the two communities of DIY hobbyists and computer enthusiasts.
- As soon as something “official” releases, there are half a dozen “forks” that have splintered off. This serves to dilute the overall user experience, causing bewilderment and disorganization.
- As a result, newer users aren’t sure where to start to get things up and running.
- Knowing where to turn for help is equally difficult. Because the dragon has a dozen heads, you might have to slay them all before you master the thing.
I have on my work bench a handful of Arduino-esque stuff, virtually all of it non-operational hardware (so far):
a) A Pololu AVR programmer
b) A Sparkfun Pocket AVR Programmer
c) A homemade ISP programmer
d) An Arduino UNO
e) A relay development board with ATtiny2313 MCU
This was a replacement for (b), promising to be more better faster. At least this manufacturer’s drivers are self-hosted, i.e., they make their own suite of drivers. It’s not some arcane foreign package, managed by yet another third party, long defunct. And yet… damned if the thing won’t work. I get the dreaded Exclamation Point of Death.
This is a hopeless mess. Sparkfun’s driver link just goes nowhere. After a half an hour of reading and clicking, I stumble over to another vendor’s site and find some hearsay about yet another suite of drivers that allegedly work. Finally this installs, but there’s no COMM port listed in Device Manager. So, none of the software tools can recognized the thing.
I was foolhardy to think I could make my own programmer from scant directions on the interwebz. That was just a big fail.
My first Arduino dev board, the Uno, does not work. I plug it in, and most of the time no machine will recognize it. No “bonk”, no “ding”, nothing. I took this to my office and gave it to my technicians who are well accustomed to working with QC and microscopes and fancy solder reflow equipment. They found nothing distinctly wrong with it. And yet it clearly doesn’t work.
I found that if I bend the Uno board a bit (yes, bend), I can get Windows Device Manager to wiggle a bit. So there appears to be an inner layer fault, most likely a trace intermittence. Lovely. Another brick for my pile.
To program the AVR chip, I turned to these sprinkling of software tools that purport to do so:
- AVR Studio
The top three have been dudes for me so far. I’m yet to try the gold standard, AVR Studio. After all, this is published by the manufacturer of the MCU…
The only piece of hardware above that I got to work was the relay I/O board. And you know how I did it? With a Freescale HCS08 dev board. Not an AVR chip or an Arduino board. The S family of chips is simply lovely. It’s soothing. It’s a fresher breath of air, having inhaled the stale aroma from the Arduino “hackerspace”.
But to be fair, Freescale is my comfort zone. I cut my teeth on the Motorola HC11. So it stands to reason that I’d favor that flavor.
The uniformity of experience in going from a line of C code to a hex file burned onto silicon is now even more valuable to me. The Freescale “way of doing things” is a much more pleasant thing. One application (CodeWarrior) weighing in at a hefty half gig, published by a single vendor that also happens to design and fab the chip you’re using, is all you need. Start to finish. That’s power.
I should note right here and now that I’m actually the biggest supporter of the Open Hardware Movement and the philosophies that Arduino espouses. There have been countless amazing creations achieved with this platform.
It’s in the implementation that I’m disappointed. Frankly, I’m surprised that the masses aren’t as frustrated as I am. I suspect that this is indicative of a greater public movement: that of DIY culture invading every corner of the marketplace. The software (or tool, or apparatus) doesn’t work as advertised? No sweat, just hack it!
And that ethos truly is something to celebrate. Kudos to the Everyman who fixes something rather than disposes of it, complains, and buys a new one.
But coming from the engineering and product development side of the aisle, I’m forced to side with the philosophies of coherent and esthetically pleasing user experience. This has value too, just as much (I would argue) as the value of DIY, crowd-sourced electronic hobbyism.
My office was liquidating a bunch of old computer equipment. In the heap, my eye was caught by a Dell box. “Hmm, what’s wrong with that computer?” And so began my next big obsession.
We have one of these little do-dads for our kid: HoMedics SS-3000 Soundspa Lullaby. It’s a nifty little product, makes different simulated white noise sounds and projects these images from a spinning disk apparatus. Like I said, nifty.
But also fragile, and prone to breakage. The company, HoMedics, replaced our first one because its little motor that turns the disk just quite one day. Well, the replacement now has the same symptom.
So enough was enough! Time to tear this thing apart.
It’s a complicated little gizmo. I had some difficulty separating the front from the back housing, but if you shove a flat head screwdriver into the side, it will pop out.
After get the motor assembly all torn apart, with some simple tests, I determined that the motor magically worked again. In my estimation, the point of failure here is misalignment of the projector disks with the engaging gear drive.
You see, HoMedics is relying on the forgiving tolerances of the plastic gears in the motor drive system, such that when you engage the projector disk into the disk bay, there will be proper alignment. I believe this isn’t a safe bet. When you feel resistance flipping the switch, that means the gears aren’t in alignment. Don’t proceed! This will dislodge the worm gear and your motor won’t turn anymore.
Or at least that’s my educated guess.
A while ago, I modified my daughter’s little kid kitchen. In that project, I found my design self teetering on that edge between two goals: get-it-done on the one side, do-it-right on the other. I had chosen the former and even my 2 year old (at the time) could see that this was a critical design mistake.
As a quick refresher, I had thought Those Thoughts 1. “Wouldn’t it be cool if her cute little IKEA oven had a light that turned on when the cute little door was opened?” Well, yes, but perhaps it would have also been cool if I’d considered the very likely fault condition wherein my toddler would leave the door open. Toddlers do that.
And you guessed what happens next: batteries died.
A very wise engineer once told me, “Rob, there’s never enough time to do it right the first time. But there’s plenty of time to fix it later.”
Well, here I am, fixing it finally.
I knew that a timer was in order. So I blew the dust of my Forrest M. Mims III Radio Shack booklets, particularly the indispensible 555 timer book.
When I was done, this is what I cooked up:
So to explain the “truth table“, the operation works like this:
- user (in this case, the kiddo) opens the oven door
- added lights inside oven turn on and remain on for about 10 seconds
- if user does not close door within this time, the lights go off to conserve battery life
- closing the door within the time frame resets the timer and turns the lights off
One other critical circuit requirement that the above Mims diagram does not account for was with the trigger input. His classical circuit only triggers on level changes, active low. In other words, for as long as the input is held low, the timer would be in standby.
That wouldn’t work for me, since I wanted the timer to start when the door opened. That’s an edge-sensitive requirement. I found a nice, easy capacitive switch solution:
The results, finally, were as they should have been: nice well-lit oven that doesn’t wear out the toy batteries. My engineer buddy would agree.
My garage has a single light switch in it for its overhead fluorescent lights. This light switch is not conveniently located; it is situated beyond our freezer, such that one has to walk into the darkened garage in order to turn the switch on. So I made an electronic 3-way switch. “Why?”, you ask. Indeed. My reasons are always convoluted and sometimes irrational. Best not to ask such questions.
But if you must know, our garage is mostly finished with drywall, so adding a second “3-way” switch would have been difficult. I opted for an electronic switching circuit 1.
First, start with the napkin diagram:
The core of the design revolved around a JK flip flop. Rockin’ this project with 30 year old technology.
For the mechanical switch, I removed the AC switch and used a surface-mount garage door momentary contact switch. The wiring then can also be garage door opener grade, small current wire (since this input to the circuit is on the low-voltage digital logic chip).
Here are some photos of the final project:
Full Project Album:
I ran across this most excellent xkcd comic the other day:
It’s just so funny on so many levels, if you’re a EE. Let’s just go clockwise around the page, starting at the top left.
- I love that the battery voltage is a square root. Just so obscure and mathematically nerdy.
- Gluing open the switch? Ha!
- That PNP transistor has two emitters, look out! Crashing electrons!
- I like that the printed value of the resistor isn’t explicit; just the color code is written. Priceless.
- Solder blob, yes! Any engineer worth his salt relies on solder blobs during prototyping. It’s especially funny that this blob is shorting out a bunch of parts.
- 666 timer. Why didn’t I think of that one? The 555 timer has had too much fun for too many years.
- Magic smoke bottle. Again, just so funny.
- Just try to do some nodal analysis on that resistor network!
- Holy water, tear collectors, and sandals… wow.
- “Hire someone to open and close switch real fast.” I laugh out loud each time I read that.
- Most expensive chip available — I used one of those in my senior design project!
- Arduino for blog cred. That’s so trending now.
- I’m afraid that 50V battery isn’t going to last long.
- Hot glue. Man, if I had a nickel for every time I whipped out the hot glue gun…
Insider parodies like these really crack me up. I’m reminding of the Death Waltz musical score, also comically brilliant in its absurd complexity. My wife reminded me of some music that her choir performed by ” PDQ Bach” 1. Here’s a delightful such performance:
In the professional world, it’s always good to have a sense of humor with regard to your work, whether it be circuit design or classical music.
She has a Pantech P7000 flip phone, but it stopped charging. I asked a few questions first to understand the nature of the problem. For instance:
- Has she tried other wall chargers? Yes, all give same symptoms.
- Has she tried other batteries? Unknown.
- Has she tried wiggling the cable to see if it makes connection? Yes, and it does.
The first thing I did was have a look at the charger, just to test out the verbal info I gathered from James. With a set of helping hands, I probed out the power and ground pins:
I saw a nice steady +5V, so the charger was good. Although its plastic shell was a bit wobbly, it seemed to be functional still. Now, onto tearing apart the phone.
I couldn’t find a tear-down guide online, so I had to figure it out for myself. There’s one obvious screw above the battery compartment:
But I had a hard time finding the other hidden screws. Turns out, there are four hiding underneath a bezel surrounding the keyboard:
Once those are gone, the assembly comes apart rather easily:
Now the back shell can be removed. When I did, the charging connector tumbled right out. So it was no longer even attached to the PCB:
Here is a closeup of the connector:
You can even make out the copper pads still attached to the pins, which have ripped off of the PCB. That’s never a good thing! This type of damage is actually quite common in consumer electronics. This interface isn’t always well designed on most cheaply produced gizmos. And yet, it’s an area that is very high-traffic; in other words, the mating cycles of the charger or serial cable to the phone is always quite high. As a designer, I would prefer these interfaces to be more robust. But then, I’m more interested in lifespan of my electronics, whereas most electronics companies would prefer you buy new products every 6 months. I digress.
At this point, I wasn’t yet sure I could repair this. There was significant damage to the PCB pads (some pads entirely gone!), so I first cleaned off the remaining pads by re-tinning 1:
Next, I cleaned off the pins of the connector. Then I re-placed the connector down on the board and soldered it back on. I got maybe 80% coverage of pins to pads. The number of pins on this connector is maybe 10-12; obviously only 2-4 of which are used for the power charger. So all that was strictly necessary were those sets of pins. As luck would have it, those power pins were still intact. The phone is back to life!
Full Project Gallery:
You remember the first phase of the iPod jukebox, yes? To jog your memory, the basic goal was simple. How do I make these dust-collecting components:
…work with my iPhone in order to have music in my workshop? Simple concept, not so simple electronics. The project is mostly a connectivity issue, i.e., there are tons of inputs and outputs that must all be managed with connectors and wiring and power regulation.
On paper, the system looks something like this:
In Phase 1, I had done a substantial amount of wasted work with one such cable: the audio/power cable for a first & second gen iPod. Since the project had been shelved so long, several generations of iPods and now iPhones have come and gone. Well, in that time, Apple has settled on USB as their power bus of choice, rather than FireWire. Thus, I had to likewise change directions on this project to accommodate my iPhone (rather than the antiquated iPods). Mounting options naturally have to change as well. And the overall enclosure gets modified too. It’s quite a ripple effect when your central component (the music player!) gets the switch-aroo.
I was locked in a brain-freeze for quite a while on this part, the mounting and enclosure. I had been stuck on the idea of trying to make a “pretty” Apple-esque Plexi box. But I finally admitted to myself that this is just above my skill set. I have a hard enough time making ugly black plastic kit boxes look pretty, let alone clear Plexi where blemishes show so easily.
So instead, I’ve decided to embrace ugly. Why not just make this phase of the project an intermediate step rather than the final step? My garage is already an acceptable and appropriately dirty place, as is the attached workshop. Just let this jukebox fit in with that kind of environment.
So I completely re-thought the enclosure phase. I began cobbling together other old cases, car mounts, and such to make a quick enclosure that would be practical, yet secure. Such parts included:
In putting all these items together, it now (unintentionally, I assure you) might resemble something else entirely, as you’ll see in the project gallery below 1. But hey, this jukebox does reside in the man-cave after all.
What’s in store for Phase 3? Coming soon, I’ll package all this mess a little nicer. I have some connections in the machine shop world. I also will reveal this gizmo’s name, so stay tuned.
A while back, a guy contacted me through my blog about contracting some monitor repair. He had come to acquire a bunch of LCD monitors that all had failed in similar fashion. So I took him up on his offer to repair them so he (and I) could resell them all.
Continue reading “Samsung LCD monitor repair”