[John] wrote in with a solution to a prototyping issue that has vexed us for quite some time. Above you can see the DIP friendly solution for dual-row pin headers which he came up with. With just a bit of easy soldering he now has a breadboard friendly device for prototyping.
He starts by soldering a dual row pin header on the board, then clips off all of the legs on the outside row. The row of legs that remain are then inserted into one side of the trench on his breadboard. The other side of the trench has a single row pin header, and he solders them to the outer row on the breakout board using another single pin header aligned horizontally. This isn’t a 100% convenient solution, as it’s still pretty hard to get your jumper wires in the breadboard on the side covered by the breakout board. But if you plan in advance you can place your wires first, then plug in the development board.
Here [John] is working with TI’s eZ430-RF2500 board. We’d like to go back and remove the dual pin socket we soldered on our eZ430-F2013, replacing it with this style of pins.
[Armin] recently pulled out his Commodore 64 and looked back on the projects he did as a kid. The surprising thing is that we’re not talking quite as far in the past as you might image. He was 13 in 2002 and the family didn’t have a PC. But more than a decade before his father had purchased a C64 and [Armin] dug into the manual to teach himself how to code. This week he connected the old hardware to his video capture card to give us a demonstration on what he accomplished.
He had seen Windows 95 at the local computer club and figured why not program a clone of the software for the machine at hand? He called it Windows 105 (because that number is higher than 95) and worked out ways to mimic programs like DOS, Corel Draw, Notepad, and some of the programs from Microsoft Office. They didn’t include all the functionality of the real thing, but the look was there.
The story does have a happy ending. [Armin’s] parents saw what he was doing and managed to pick up a PC for him to play with. Now he’s a professional programmer looking back on the formative years that got him there. We’ve embedded one of his demo videos after the break for your enjoyment.
Continue reading “A nostalgic look at what a 13 year old can do with a C64”
The 7400 Logic Competition has drawn to a close. The winners were announced and there are quite a few of them. There were fifteen first place winners named, nine second place, and nineteen third place projects. The bounty of quality entries is a testament to the popularity of the contest. It helps to have a wide range of prizes and the post linked above lists all of the sponsors who donated goodies as an incentive.
The board seen above was awarded the reader’s choice, to which the grand prize was awarded. It is a 7400 series calculator. [Umair Mukati] and [Naveed Ahmed] — both are students at the Institute of Industrial Electronics Engineering in Karachi, Pakistan — developed the device as part of a class project. It is capable of adding or subtracting two digit numbers. This includes support for negative numbers as results. We’ve embedded a video demo of the calculator in action after the break.
Continue reading “7400 Logic Competition winners announced”
[Chris] set out to build a monitoring system for his water heater. It doesn’t Tweet or send SMS messages. It simply lights up an LED when the water heater is active. The one thing that complicates the setup is that he didn’t want to pull any wire from the garage into the house. What you see above is the wireless setup he used to accomplish this goal.
This is an electric water heater, so [Chris] patched into the 230V heating element feed. When the water heater is idle this connection is cut off. He used a transformer to step the voltage down to 17V and rectified it before feeding a 7805 power regulator. The rest of the transmitter circuit consists of a 555 timer driving the coil seen on the left. It is made out of telephone wire, with each of the four conductors inside connected together to multiply the number of windings. The box of breakfast sausages hosts the receiver coil. His hardware takes the induced current from that coil and amplifies it, feeding the signal to the base of a transistor responsible for switching the status LED. This works through the 6″ thick garage wall, although he did have to use a battery on the receiving end as his wall wart was injecting way too much noise into the system to work.
You’ve got to admit that custom milling your own wedding band is pretty hard-core. In this case [Jeremy Swerdlow] is making it for his friend, but that doesn’t diminish the fun of the project. After the break you can watch him mill a titanium ring and wrap it with a palladium inlay.
To solder palladium to titanium [Jeremy] would need special equipment, so he found another way to mate the dissimilar metals. He milled a dovetail groove in the center of the titanium band. To do that, he had to make a special cutting tool that was just the right size. Once had milled the ring’s rough dimensions, he had to fabricate a custom mandrel to hold the ring for the rest of the job. The dovetail was then filled with a palladium strip using a combination of heat and hammering. The two ends are soldered together using palladium solder. The ring in the middle shows this solder joint. To the right is a ring after the inlay is milled flush but before the final polishing which will bring out the best qualities of both metals.
If you don’t have the machine shop skills to pull this off you could always try your hand at 3d printed rings.
Continue reading “The wedding band: milling titanium and wrapping it in palladium”
Okay, we think it’s questionable when people say they have no problem soldering QFN packages, but BGA? Granted this chip has far fewer balls on it than many, but it’s still quite impressive that [Xevel] was able to solder this BGA breakout by hand.
The chip you see above is a TMP006 infrared temperature sensor from TI. [Xevel] picked up the part but didn’t want to break the bank when prototyping by buying a proper PCB to host it. There are only eight conductors on it, arranged in a grid with 0.5mm pitch. That didn’t seem to scare him off, as the video after the break shows him connecting each to a conductor on a hunk of stripboard.
[Xevel] mentions that this is a dead-bug style project. Usually you glue the part upside down when using that technique, but it needs line of sight to get an accurate temperature reading so he first cut a hole in the substrate. We’d bet he’s using wire-wrapping wire to make the connections. It’s a very fine solid core wire which is perfect for this kind of work.
Continue reading “Hand soldering BGA parts should be a circus act”
Whenever we hear about ECE 4760 we take notice. That’s because a ton of fantastic hacked together projects have resulted from the class. It’s offered at Cornell University and focuses on designing projects based on microcontrollers. We look at it as a ‘how to connect everything to your microcontroller’ guide. The good news for you is that 34 lecture videos from the Spring 2012 ECE 4760 class are now available to watch for free online. When coupled with the course webpage itself (which outlines the reading, labs, and homework) this turns into an opportunity to work through the entire course on your own schedule.
If you need a brief preview, here’s a couple random things we’ve seen as final projects from the course: a digital saxophone, a handwriting decoder, and a haptic feedback unit for building your biceps.
We’re still working our way through the Nand2Tetris project, but we’re putting these lectures on our watch list for later.