In the past I’ve expressed a negative opinion of Arduino, I’ve described it as an overpriced solution for people that are too lazy to learn a real microcontroller. At this time I am completely flip-flopping on this opinion
. The Arduino is in fact a fabulously useful and reasonably priced tool that every nerd should own. In the past I felt that at $30 or so per unit was too expensive to actually use for anything On the Internet you see numerous electronics projects with an Arduino at its heart and this isn’t really what’s intended. The Arduino you see is actually a prototyping tool, that’s not a secret, they say so on the website very near the top of the page. However for a long time I failed to appreciate what that really meant. Hopefully I can rescue someone from my mistake.
The intended use you see,is to come up with An Idea, throw it together with bread boards and dead bug and tape and glue and whatever, and your Arduino! Then you can write your code, find out if your idea really works, get everything debugged and then you can design a board and build your device for keeps. Your Arduino goes back on the shelf for your next project and your board gets populated with an atemel microcontroller that runs between $3 and $4 depending on where you get it.
In the beginning of course all your projects are based on the same atmega 328 that the Arduino Uno is based on however this provides an excellent gateway to using many other atemel microcontrollers several of which have their own Arduino’s based on them. In short, Arduino’s are awesome, I was totally wrong about them, and you’re going to see a lot more of them here.
At some point in your life someone may have told you that a metal lathe is unnecessary, you can do the same thing with a power drill and a file. More than likely this person was an old man and you chucked up the comment to ignorance or dementia, I know that’s what I always did. Apparently that old guy isn’t crazy after all.
Recently I developed a need for a 9 mm fine thread bolt. Now you may or may not be aware that even size metric bolts are widely available but the odd sizes are very, very rare. I’m not sure why this is, probably a manufacturing conspiracy, but I’ll rant about that another time.
The solution is simple, Acquire the next size up, 10 mm in my case, Long enough to have no thread over the length I need to install my thread. Reduce the diameter, cut to length, and run a die over it. Bob’s your uncle.
This bolt is going to replace the handle in my tripod head, on occasions when the handle is in the way.
For some time I’ve been meaning to learn the skills necessary to fabricate custom PCBs at home. This is been on my to do list literally for years, since childhood in fact. Recently a project came up that gave me an opportunity to put the final pieces of the puzzle together and finally get off my butt and build something. No one else in the world will find this as jaw-droppingly fascinating as I do, but nonetheless here it is.
This is a 12 volt voltage regulator, it’s designed to handle 15 A but since I don’t quite know what I’m doing it needs a little tweaking to get there.
But I’m not really into talking about the circuit today, it’s etching the board that I’m gleeful about today. The entire process needs some refinement, I’ve used 1/16 inch 1 ounce board stock, since 15 A is the target 2 ounce copper may be more appropriate but since it took almost 2 hours to etch I’m happy with the 1 ounce at this point. I used homemade copper chloride etchant, it also needs some refinement in addition to the 2 hour etch time, the colors isn’t right, too dark.
I’m very happy with the final result, however there’s numerous faults to pick on. There are brown stains on the copper in numerous locations, this is where the etchant was beginning to break through the resist, not the end of the world but something that needs attention. I don’t currently have a plan to control the tarnish on the bare copper, I’d like my boards to be shiny in the future. There’s also a routing issue here, the upper two terminals are connected by a trace running around the lower perimeter of the board, this is ground. The lower two terminals which reach across the bare ground trace are positive, obviously this is not ideal. On this board I’m using traces 2 mm wide, these work very well but I suspect if I where using the much finer traces common today, I would not have had nearly as good luck.
But that’s all solutions for another day. Today I designed it, etched it, populated it, powered it up and it worked, no explosions. I’m pretty happy with that.
There doesn’t seem to be a whole lot of information online on the subject of installing a real operating system on popular sub-notebook computers. These handy little machines inevitably come with Windows 7 starter installed, the manufacturer seems to believe this is all a computer needs, it’s my opinion that seven starter is only appropriate to assess the quality of the screen before purchasing, you bring it straight home and put a real operating system on it whether it be win7 home or professional or your favorite flavor of Linux (if you’re into that). emachines actually declined to answer a driver related question on the grounds that I had installed an unsupported operating system, that’s not the way I see it.
The most common method, these days of installing Windows on a machine with no removable media drive seems to be to transmute the Windows CD onto a bootable USB thumb drive. Perhaps it makes me a failure is a nerd but I’m just not feeling it. Even with software tools various companies have developed specifically for the purpose it takes quite a bit of fiddling to get a working bootable copy of the modern Windows kernel onto a thumb drive. It’s just too much effort and not enough reward for my taste.
My approach is to use a standard everyday CD drive, plugged into USB using an IDE/ATA/SATA to USB adapter, similar to this one. I got mine on eBay from a seller in Hong Kong for about $8 shipping included, it’s most likely a counterfeit version of a unit some American company sells for $40 however it works just fine.
After a quick visit to the bios to make the CD drive the primary boot device the installation is smooth and uneventful. It should be noted that this adapter translates the true identity of the device it’s connected to, I used some such adapters where anything plugged into it shows up as a generic mass storage device, not the case here. This means you can plug it into a CD burner and actually burn CDs with it, or plug in a hard drive and remove and re-create its partitions. It also means it shows up in the bios boot device list as USB CD-ROM drive which you can leave the primary boot device without having the computer attempt to boot off of every thumb drive you inadvertently leaving in it.
The install completed with only two unknown devices, one being the wireless network adapter which Windows had no trouble digging up a driver for with a click of the update driver button. The other is the graphics adapter and that one is the source of my being peeved at emachines.
The driver provided on the downloads page does not say what operating system it is for(I know now that this is because Windows 7 starter is the only supported operating system for this computer) when you attempt to install this driver(either version), you Get an uninformative error saying your machine does not meet “minimum system requirements”. I e-mailed them, assuming there is a simple technical glitch in their webpage and that they would reply with a link to the driver I needed. In the reply I received however I was very politely told off for having installed an unsupported operating system on my machine!
A little bit of additional googling led me to an excellent review on notebookcheck.com that identified the graphics hardware used in the machine. One more consultation with the old man Google brought me straight to Intel’s driver download page and I was up and running in a snap, no thanks to emachines.
After reviewing my video stitching experiment I came to the conclusion that in order to be really impressive the camera really has to move. Obviously this leads smoothly into another experiment. The results are more interesting than the first but I must say much less successful. I mounted the cameras on my homebrew fig rig and continued my Shoreline theme. This is what it looks like.
As with my first experiment, this is assembled with premiere Pro. Starting with a simple pan across the rocks the first problem is immediately apparent, there’s a severe exposure mismatch. As the camera swungs around and the light evens out at about 15 seconds the scene looks pretty good. I could’ve corrected this by applying a brightness/contrast adjustment to both frames and animate the adjustment to follow the changes, but life is just too short. The mismatch starts to show again at about 24 seconds.
At 33 seconds I cut to a moving shot walking across the beach, exposure mismatch is still present but a few more flaws come to light as well. The walking introduces a vertical motion since the cameras are obviously not synchronized the corresponding frames on the left and right are actually captured at different times since I’m shooting at 10 frames per second synchronized to the nearest frame the difference can be up to 1/20 of a second. In the almost completely stationary shot of my first experiment this isn’t apparent at all, however with the fast vertical pan the problem is severe.
Further I believe this effect is responsible for the small misalignment of the waves in the bottom center of my first experiment, I could never get those to align quite right.It might be possible to correct this dynamic misalignment by stabilizing the videos in After Effects before stitching them together however, a far better solution would be to shoot the video at a higher frame rate. If shot at 60 frames per second as is commonly available in better quality consumer cameras, I don’t think the effect would be noticeable. It’s definitely a lot more work to fix it in post at any rate.
At 1 min. I begin to walk down the steep bank to the waters edge. The horizon moves up to top of frame revealing a very distracting distortion. I thought at first this was lens distortion taking effect at the edge of the camera’s field however it’s actually a perspective distortion. As the rig as a whole tilts down in the pitch axis each camera rotates in the roll axis with respect to its Horizon. Thus, in this configuration the rig must stay level for convincing output.
This idea kind of popped into my head fully formed one morning while I was loading my dive gear. I only needed a few minutes to build the hardware, and the shoreline of the dive site would be a lovely subject of the experiment.
Every digital camera nowadays has a feature to help you stitch overlapping photographs into panoramas I thought why not use multiple cameras and do the same thing with video. There’s nothing earth shattering about this idea it’s essentially the same thing that Google does to create street view and do a lot better job of it than I have (but they spend a lot more money on it)
What I’ve got here is a 10 inch long piece of strap aluminum with a quarter-inch hole drilled in either end and a tapped 1/4 20 hole in the middle. This allows me to mount two cameras on the tripod and point them together as a unit. These are a matched pair of Canon powershot A430s that I got on eBay for cheap. The cameras are secured with homemade thumb bolts that originally made for my fig rig.
There are few details about this that beg further discussion. The two videos were stitched together in Adobe Premiere Pro, I’m not going to go into how to use premiere Pro, if you know how, this task is fairly straightforward and learning premiere Pro is beyond the scope of this discussion. This can of course be accomplished with whatever nonlinear video editing system you prefer.
The first step is temporal synchronization of the two video clips. Right after I started the cameras I clapped my hands behind them impressing the sound on both audio tracks. You simply play through the clip and identify the frame during which the handclap occurs setting a numbered marker at that frame. The marker follows the clip through its journey from that point on. Once both clips are on the timeline you simply align the two markers.
You’ll notice that misalignment of the two video frames is visible at points one and four, this could’ve been eliminated by masking a few pixels across top and bottom.
The A430 is nearly decade-old technology and was a low-cost camera from its inception as a result it has trouble with some more demanding photographic situations. The left camera was getting a little too much sunlight in the lens which it tolerates poorly. I needed to make significant adjustments to the color of the left frame to make it blend with the right frame, even so the seam is still visible and the left frame is noticeably lower quality than the right frame. Also the camera only shoots video at 10 frames per second which kinda shows up once you’ve blown it up and rendered it at 720p high definition like I did.
To align the two frames I put the right frame on top and set it’s opacity to 50%, and used the rock at point 3 as a fiduciary mark, moving around the right frame until the two rocks blended into one. Due to lens distortion (which I did not attempt to correct) there is increasing misalignment the further from that rock you get. This is apparent at point 2 right next to widely known local landmark, Cape Forchu lighthouse(Barely visible). At point 5 another local landmark, bug light can be seen. There’s also misalignment visible in the rocks at point 4.
When I have occasion to do this again I’ll be sure to get a shot of a high contrast object in the center of the combined frame to provide a good marker for alignment.
More work in postproduction and more care in shooting could have eliminated most of these artifacts however perfection was not really the point of the experiment and in my opinion the artifacts add interest to a composition which is otherwise very boring. I actually recorded 26 min. of this, during that time the passing of the seagull was the only break in the monotony.
I never did get that dive in, although it doesn’t look it in the video (I left out the audio of wind whistling in two microphones) the weather was actually terrible for diving.
The monitor got installed in the boat the following weekend, and it worked perfectly. Sort of. Not really. When exposed to direct sunlight, a frequent occurrence where it’s installed, the screen fogged up so as to completely obscure the display.
Clearly this is a case of moisture contamination so off the boat and back to the bench. I opened up the casing, which I deemed unnecessary in the first pass but clearly I had to go a little deeper. I was hoping to find lots of high density foam rubber like what you see everything mounted in inside of a Panasonic tough book. That would provide an easy scapegoat for where the moisture was hiding, but alas, everything inside was solidly constructed with no obvious antivibration/impact mountings. But no matter, the moisture had to be hiding in there somewhere. The guts was all in a single assembly with the screen backlight and mainboard all attached and rigidly assembled. Sandwiched between the casing halves and secured with the same screws, with none of the dangling boards and parts secured with tape you normally run into when you strip the screen out of a monitor.
I grabbed a folded blanket out of the cupboard and put the screen assembly in the middle of the stack with a remote probe thermometer underneath it. I put heating pad about five layers lower and turned it on low. An evening of twiddling with the distance between the heating pad and the screen while watching TV got the assemblie safely holding at the target temperature.
Although I didn’t have specifications for the parts in question I assume that the screen itself was the most heat sensitive component and did a little googling. Determining that 120°F to 130°F would be nice safe maximum storage temperature for the screen.
I left that to cook for 48 hours and performed a few more tweaks to the casing. The stripped screw on one of the cover panels on the back got passed over on the first run through as unnecessary, I feel differently about it now. The closest larger screw I had on hand was #6 course so I drilled and tapped the stripped hole to fit.
The day night toggle switch on the bottom had a crack in its rubber boot, the day night function wasn’t really necessary as the software provides the same functionality so I eliminated the switch and sealed the hole with a stainless steel screw and a rubber washer.
The monitor has been back in service for a couple weeks now and the fogging problem has not returned. Perhaps in future we will all be wary of moisture problems in electronics that has spent significant time in someone’s basement.
Probably should’ve taken a picture that, oh well, you can’t think of everything.
The boat came off the top of a rather large wave, going a little too fast and landed on the up swell of another rather large wave. This abrupt stop snap the monitor against the windshield and broke the back light in the monitor(the windshield was fine). My resourceful dive buddy in telling the story in various places was able to acquire a previously loved marine grade monitor, before the following weekend no less.
In this photo it’s pretty much in its post tuneup splendor. When it came to me the color was entirely wrong, on closer inspection the red was missing. The classic bent pin in the connector wasn’t the issue. End to end continuity testing narrowed the problem to the cable so the connections inside the connector housing were now the prime candidate, and so it was.
This monitor being intended for marine applications it runs on 12 V DC which is connected to the VGA connector to avoid multiple cables.
Here we see it with the connector shell removed, the barrel socket for power is in the foreground.
In this image we get a good look at the questionable soldering, some of its mine, most of it isn’t. At some point in the history of this monitor the connector was replaced with the unit harvested from scrap. You can see the casings has been trimmed with the dremel tool in the connections are electrically adequate (at least they were) but mechanically questionable. It’s more than a little bit ugly but it gets the job done I most likely would’ve done it just the same way, only difference being…
I would’ve cleaned with alcohol and covered the connections with nice blob of hot glue being sure to get it well stuck to the connector housing and the wire insulation in order to mechanically isolate the delicate electrical connections. Now it’s fit for a good size wave.
The monitor also comes with a perfectly serviceable custom-made aluminum bracket, very robust but missing a few details. The monitor slides into it from the bottom it’s a snug fit and although it can’t get out there is actually nothing holding it up, well there is now.
The wooden block fits snugly in the cutout on the back of the monitor. Underneath the block he can see and access panel, this is a watertight gasket and conceals the buttons for horizontal and vertical size and position as well as an enigmatic mode button. To the upper left is another watertight panel which conceals the cable connections inside it is a stripped screw so I backed it up with the handymans secret weapon (in black). Also visible as a black watertight toggle switch in the lower right. Everyone involved assumed this was the power switch however in actual fact the monitor doesn’t have the power switch. The watertight toggle is in fact a day/night switch, it dims the backlight.
The unit came to me without any bolts to hold on the till base. I felt a no tools solution was in order. I used a three-quarter inch 1/4 20 bolt with a small T-bar brazed on to prevented it from spinning, along with a couple washers and a standard hardware store thumb nut. The bracket was sized to use friction washers, there was a few crumbs of the originals left, it resembled a pencil eraser. I replaced them with a circle of innertube rubber.
Does anyone know what a fig rig is? Unless you’re a film nerd you probably don’t, until recently I didn’t. A fig rig is in fact a video camera accessory, it consists of a length of steel tubing rolled into the circle with the crossbar on which to mount your video camera. It very much resembles a steering wheel with the camera mounted in the center. The point of this peculiar contraption is to get steadier shots with modern lightweight digital cameras without the flexibility sacrifice of a steady cam.
The fig rig is the brainchild of English film director Mike Figgis and a commercial version is produced under license by the Manfrotto Group. Of course hobbyists are loathe to resort to the commercial version. Builders most commonly create the ring from PVC pipe and 45° elbows. All that gluing didn’t really appeal to me so I decided to construct my own fig rig by stretching the steering wheel analogy and building mine by modifying an actual steering wheel. (if anyone else has a leather fig rig please stand up!)
I’d love to share a detailed build log on this however the truth is most of it is pretty obvious and what isn’t is highly dependent on the individual properties of the steering wheel your able to source. So in brief, the center is of course cut out leaving the skeletal stubs of the lower arms intact. The tentative plan was to weld in the crossbar but the steering wheel frame being made of aluminum made that much less practical. So I went with a crossbar of one-inch aluminum angle mounted on screws which originally held the switches for the cruise control, they’re conveniently already true to the plane of the wheel. The crossbar has camera mounting holes for center, 1/2 inch off-center in either direction, and two widely spaced holes which allow to matching cameras to be mounted just in case I get around to shooting in 3-D one day. The camera mounting face is covered with the fuzzy side of Velcro so that the camera is held in a nice warm hug. And I made a thumb bolt to hold the camera on, just a 1/4 20 bolt nut and two washers all braized together.