Etch Your Own Circuit Boards In Your Kitchen

November 16, 2018 by Brian Benchoff 43 Comments

Right now, you can design a PCB, send it off to a PCB fab, and get professional finished boards in a few days for less than a dollar per square inch. This is fantastic, and it’s the driving force behind ever-dropping costs of hardware development. That’s great and all, but you can make circuit boards at home, easily, and without involving too many toxic chemicals. That’s exactly what [videoschmideo] did, and the results are pretty good.

The process starts with a single-sided copper clad board that would be readily obtainable at Radio Shack if there were any of those around anymore. Once the circuit is designed, the traces and pads are printed (mirrored) out onto sticker backing paper. The toner from your laser printer is transferred to the copper with a clothes iron.

The tricky part about creating a PCB is taking away all the copper you don’t want, and for this tutorial [videoschmideo] is using a vinegar and hydrogen peroxide process. If you’re using stuff you can buy at the grocery store, you’re only getting 3% acetic acid and 3% peroxide, but given enough time and enough peroxide, it’ll do the job. After the board is etched, [videoschmideo] neutralizes the copper acetate produced with aluminum foil. The end product isn’t the safest thing in the world, but aluminum salts are much more environmentally friendly than copper compounds.

Making PCBs at home isn’t anything new, but it’s nice to be reminded that you can do so even with minimal effort and chemicals that you could rinse your mouth with. Once you do, though, you’ll probably have to drill some holes in the board. Yes, you could use a dremel, but a nice small drill press is a pleasure, and well worth the investment.

With Grinning Keyboard And Sleek Design, This Synth Shows It All

October 28, 2018 by Donald Papp 24 Comments

Stylish! is a wearable music synthesizer that combines slick design with stylus based operation to yield a giant trucker-style belt buckle that can pump out electronic tunes. With a PCB keyboard and LED-surrounded inset speaker that resembles an eyeball over a wide grin, Stylish! certainly has a unique look to it. Other synthesizer designs may have more functions, but certainly not more style.

The unit’s stylus and PCB key interface resemble a Stylophone, but [Tim Trzepacz] has added many sound synthesis features as well as a smooth design and LED feedback, all tied together with battery power and integrated speaker and headphone outputs. It may have been originally conceived as a belt buckle, but Stylish! certainly could give conference badge designs a run for their money.

The photo shown is a render, but a prototype is underway using a milled PCB and 3D printed case. [Tim]’s Google photo gallery has some good in-progress pictures showing the prototyping process along with some testing, and his GitHub repository holds all the design files, should anyone want a closer look under the hood. Stylish! was one of the twenty finalists selected for the Musical Instrument Challenge portion of the 2018 Hackaday Prize and is therefore one of the many projects in the running for the grand prize!

Putting A Motor Inside A Speed Controller

October 23, 2018 by Brian Benchoff 17 Comments

One of the more interesting hacks we’ve seen this year is [Carl]’s experimentations with making motors out of PCBs. Honestly, it’s surprising no one has done this before — a brushless motor is just some coils of wire and a few magnets; anyone can turn some coils into traces and make a 3D print that will hold a few magnets. This latest advancement is something else entirely. It’s a motor and an electronic speed controller all in one.

This project is a continuation of [Carl]’s PCB motor project, which started with him routing coils for a brushless motor as traces in a circuit board. Previously, we’ve seen [Carl]’s motor spinning on its own with the help of a small hobby ESC / motor controller meant for model planes and drones. This time, we’ve got something different. It’s an entire controller and motor, integrated into one single PCB.

This is a very, very small motor and ESC combo. The motor driver is a 3x3mm QFN package, and most of the other components are 0201. The main parts are a very tiny triple half-bridge motor driver and a PIC16F microcontroller. This PIC reads a hall sensor to detect the speed of the motor, and with just three pins — power, ground, and a PWM pin — this motor can spin at a set speed.

The future goals of this project are to make it work just like any other hobby ESC — just plug it into a servo controller and let ‘er rip. Since this motor with an integrated PCB requires only three connections, we’re looking at a great tool to add motion and rotation to any project. It’s fantastic, and we can’t wait to see something like this in robots, toys, and other home goods.

Continue reading “Putting A Motor Inside A Speed Controller” →

Seeing A Webcam’s PCBs In A Whole Different Light

October 12, 2018 by Dan Maloney 13 Comments

When it comes to inspection of printed circuits, most of us rely on the Mark I eyeball to see how we did with the soldering iron or reflow oven. And even when we need the help of some kind of microscope, our inspections are still firmly in the visible part of the electromagnetic spectrum. Pushing the frequency up a few orders of magnitude and inspecting PCBs with X-rays is a thing, though, and can reveal so much more than what the eye can see.

Unlike most of us, [Tom Anderson] has access to X-ray inspection equipment in the course of his business, so it seemed natural to do an X-ray enhanced teardown and PCB inspection. The victim for this exercise was nothing special – just a cheap WiFi camera of the kind that seems intent on reporting back to China on a regular basis. The guts are pretty much what you’d expect: a processor board, a board for the camera, and an accessory board for a microphone and IR LEDs. In the optical part of the spectrum they look pretty decent, with just some extra flux and a few solder blobs left behind. But under X-ray, the same board showed more serious problems, like vias and through-holes with insufficient solder. Such defects would be difficult to pick up in optical inspection, and it’s fascinating to see the internal structure of both the board and the components, especially the BGA chips.

If you’re stuck doing your inspections the old-fashioned way, fear not – we have tips aplenty for optical inspection. But don’t let that stop you from trying X-ray inspection; start with this tiny DIY X-ray tube and work your way up from there.

Thanks for the tip, [Jarrett].

Inductance In PCB Layout: The Good, The Bad, And The Fugly

September 28, 2018 by Bil Herd 39 Comments

When current flows through a conductor it becomes an inductor, when there is an inductor there is an electromagnetic field (EM). This can cause a variety of issues during PCB layout if you don’t plan properly, and sometimes we get burned even when we think we have planned for unwanted inductance and the effects that come with them.

When doing high speed logic we need to be able to deliver sudden changes in current to the devices if we want to have proper switching times and logic levels. Unfortunately inductance is usually not a friend in these circumstances as it resists those sudden changes in current. If the high speed devices are driving capacitive loads, which themselves are resisting changes in voltage, even more instantaneous current is needed.

Simply put, inductors resist a change of current, and can act as a low pass filter when in series with the signal or power supply flow. Inductors do this by storing energy in the flux surrounding the conductor. Alternatively capacitors resist a change in voltage (again by storing energy) and can act as a high pass filter when in series with the signal. This makes them a valuable tool in the fight against unwanted inductance in power supply distribution.

In the video below, and the remainder of this article, I’m going to dive into the concept of inductance and how it affects our design choices when laying out circuit boards.

Continue reading “Inductance In PCB Layout: The Good, The Bad, And The Fugly” →

Epoxy Fix For A Combusted PCB

September 26, 2018 by Dan Maloney 29 Comments

When the Magic Smoke is released, chances are pretty good that you’ve got some component-level diagnosis to do. It’s usually not that hard to find the faulty part, charred and crusty as it likely appears. In that case, some snips, a new non-crusty part, and a little solder are usually enough to get you back in business.

But what if the smoke came not from a component but from the PCB itself? [Happymacer] chanced upon this sorry situation in a power supply for an electric gate opener. Basking in the Australian sunshine for a few years, the opener started acting fussy at first, then not acting at all. Inspection of its innards revealed that some unlucky ants had shorted across line and neutral on the power supply board, which burned not only the traces but the FR4 of the board as well. Rather than replace the entire board, [Happymacer] carefully removed the carbonized (and therefore conductive) fiberglass and resin, leaving a gaping hole in the board. He fastened a patch for the hole from some epoxy glue; Araldite is the brand he used, but any two-part epoxy, like JB Weld, should work. One side of the hole was covered with tape and the epoxy was smeared into the hole, and after a week of curing and a little cleanup, it was ready for duty. The components were placed into freshly drilled holes, missing traces were replaced with wire, and it seems to be working fine.

This seems like a great tip to keep in mind for when catastrophe strikes your boards. There are more extreme ways to do it, of course, but perhaps none so flexible. After all, epoxy is versatile stuff.

Touch Anything And Everything

September 19, 2018 by Brian McEvoy 10 Comments

Powering IoT devices is often a question of batteries or mains power, but in rare exceptions to this rule there is no power supply (PDF Warning). At the University of Wisconsin-Madison and the University of California, San Diego, researchers have gone the extra mile to make advanced backscatter devices, and these new tags don’t need the discrete components we have seen in previous versions. They are calling it LiveTag, and it doesn’t need anything aside from a layer of foil printed or etched on a flexible ceramic-PTFE laminate. PTFE is mostly seen in the RF sector as a substrate for circuit boards.

We have seen some of the wild creations with wifi backscatter that range from dials to pushbuttons. RF backscatter works by modulating the RF signals in which we are continuously swimming. Those radio waves power the device and disrupt the ambient signals, which disruption can be detected by a receiver. With a BOM that looks like a statement more than a list, integration with many devices becomes a cost-effective reality. Do not however broadcast important data because you cannot expect great security from backscatter.

[Via IEEE Spectrum]