2024 Business Card Challenge: POV Fidget Keeps Your Info In Their Hands

June 28, 2024 by Kristina Panos 4 Comments

So what if we’re halfway through 2024? People who needed to fidget all along still need something to do with their hands. So why not hand them a solution with your information on it?

Not only will this spin nicely, the spinning action will use magnets to energize PCB coils and light up LEDs for some persistence of vision action. Designing the PCB was easier than you might imagine thanks to KiMotor, a KiCad plugin to automate the design of parametric PCB motors.

Mechanical testing went pretty well with the bearings and magnets that [mulcmu] had on hand, along with a scrap PCB as the sacrifice. Although a bit difficult to hold, it spins okay with just the bearing and the shaft. Once the boards arrived, it was time to test the electrical side. So far, things are not looking good — [mulcmu] is only getting a few tens of mV out of the rectifier — but they aren’t giving up hope yet. We can’t wait to see this one in action!

Hurry! This is the last weekend to enter the 2024 Business Card Challenge! Technically you have until Tuesday, July 2nd, but you know what we mean. Show us what you’ve got!

A PCB business card that plays tic-tac-toe with red and blue LEDs.

2024 Business Card Challenge: Go Tic-Tac-Toe-to-Toe With Them

June 24, 2024 by Kristina Panos 4 Comments

There is perhaps no more important time to have a business card than when you’re in college, especially near the end when you’re applying for internships and such. And it’s vital that you stand out from the crowd somehow. To that end, Electrical & Computer Engineer [Ryan Chan] designed a tidy card that plays tic-tac-toe.

Instead of X and O, the players are indicated by blue and red LEDs. Rather than having a button at every position, there is one big control button that gets pressed repeatedly until your LED is in the desired position, and then you press and hold to set it and switch control to the other player. In addition to two-player mode, the recipient of your card can also play alone against the ATMega.

The brains of this operation is an ATMega328P-AU with the Arduino UNO bootloader for ease of programming. Schematic and code are available if you want to make your own, but we suggest implementing some type of changes to make it your own. Speaking of, [Ryan] has several next steps in mind, including charlieplexing the LEDs, using either USB-C or a coin cell for power, upgrading the AI, and replacing the control button with a capacitive pad or two. Be sure to check it out in action in the two videos after the break.

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A solar-powered decibel meter the size of a business card.

2024 Business Card Challenge: NoiseCard Judges The Sound Around You

June 22, 2024 by Kristina Panos 6 Comments

Let’s face it: even with the rise of the electric car, the world is a noisy place. And it seems like it has only gotten worse in recent years. But how can we easily quantify the noise around us and know whether it is considered an unhealthy decibel level?

That is where the NoiseCard comes in. This solar-powered solution can go anywhere from the regrettable open office plan to the busy street, thanks to a couple of 330 µF capacitors. It’s based on the low-power STM32G031J6 and uses a MEMS microphone to pick up sound from the back of the card, which the code is optimized for. Meanwhile, the LEDs on the front indicate the ambient noise level, ranging from a quiet 40 dB and under to an ear-splitting 105 dB or greater.

When it comes to building something the size of a business card, every component is under scrutiny for size and usefulness. So even the LEDs are optimized for brightness and low power consumption. Be sure to check it out in action after the break in various environments.

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2024 Business Card Challenge: Integrated Game Card

June 21, 2024 by Dave Rowntree 10 Comments

[Dan Schnur] has a simple strategy to ensure their business card stays on the client’s desk and doesn’t just get lobbed in a drawer: make it into a simple gaming platform. This entry into the 2024 Business Card Challenge is based around the tinyjoypad project, integrating an SSD1306 OLED display, joypad, and push button.

Powered by the superstar ATTiny85, the electronics are really not all that much, just a sprinkling of passives to support the display and the six switch inputs from the joystick and push button. Or at least, that’s how much we can glean from the PCB images, as the PCB design files are not provided in the project GitHub.

Leaving the heavy lifting of the software to the tinyjoypad project, the designer can concentrate on the actual job at hand and the reason the business card exists to stay at the forefront of the client’s mind. In the meantime, the card can be a useful distraction for those idle moments. A few such distractions include a tiny version of Missile Command (as shown above), tiny tris, and a very cut-down Q-bert. Sadly, that last game isn’t quite the same without that distinctive sound.

2024 Business Card Challenge: PCB Business Cards For Everybody

June 19, 2024 by Dave Rowntree 21 Comments

PCB business cards for electronics engineers might be very much old news in our circles, but they are still cool, not seen too much in the wild, and frankly inaccessible to those in other industries. For their entry into the 2024 Business Card Challenge, [Dima Shlenkevitch] is helping a little to alleviate this by providing a set of design examples and worked costs with suppliers.

Original green is still the cheapest option.

[Dima] lists key features every PCB business card should include, such as the expected thickness, restrictions for placing NFC components, and some aesthetics tips. Make sure to choose a supplier that allows you to remove their order number from the manufactured PCB, or it will look out of place.

Ordering PCBs with these specifications to keep costs reasonable requires effort, so [Dima] offers some example designs along with the results. If you want to have pretty gold lettering and graphics, you will need ENiG plating, increasing the price. Non-standard solder mask colors can also raise the price.

Will this help with the practical aspects of driving the PCB design software and actually placing the order? Obviously not, but the information provided gives you a leg up on some of the decisions so you don’t go down an expensive rabbit hole.

2024 Business Card Challenge: BAUDI/O For The Audio Hacker

June 14, 2024 by Dave Rowntree 6 Comments

[Simon B] enters our 2024 Business Card Challenge with BAUDI/O, a genuinely useful audio output device. The device is based around the PCM2706 DAC, which handles all the USB interfacing and audio stack for you, needing only a reference crystal and the usual sprinkling of passives. This isn’t just a DAC board, though; it’s more of an audio experimentation tool with two microcontrollers to play with.

The first ATTiny AT1614 is hooked up to a simple LED vu-meter, and the second is connected to the onboard AD5252 digipot, which together allows one to custom program the response to the digital inputs to suit the user. The power supply is taken from the USB connection. A pair of ganged LM2663 charge-pump inverters allow inversion of the 5V rail to provide the necessary -5 V for the output amplifiers. This is then fed to the LM4562-based CMoy-type headphone amplifier. This design has a few extra stages, so with a bit of soldering, you can adjust the output filtering to suit. An LM1117 derives 3.3 V from the USB input to provide another power rail, mostly for the DAC.

There’s not much more to say other than this is a nice, clean audio design, with everything broken out so you can tinker with it and get exactly the audio experience you want.

2024 Business Card Challenge: T-800’s 555 Brain

June 14, 2024 by Tom Nardi 12 Comments

In Terminator 2: Judgment Day it’s revealed that Skynet becomes self-aware in August of 1997, and promptly launches a nuclear attack against Russia to draw humanity into a war which ultimately leaves the door open for the robots to take over. But as you might have noticed, we’re not currently engaged in a rebellion against advanced combat robots.

The later movies had to do some fiddling with the timeline to explain this discrepancy, but looking at this 2024 Business Card Challenge entry from [M. Bindhammer] we think there’s another explanation for the Judgement Day holdup — so long as the terminators are rocking 555 timers in their chrome skulls, we should be safe.

While the classic timer chip might not be any good for plotting world domination, it sure does make for a great way to illuminate this slick piece of PCB art when it’s plugged into a USB port. Exposed copper and red paint are used to recreate the T-800’s “Brain Chip” as it appeared in Terminator 2, so even when the board isn’t powered up, it looks fantastic on display. The handful of components are around the back side, which is a natural place to put some info about the designer. Remember, this is technically supposed to be a business card, after all.

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