Designing the Second Version of my Business Card

At the end of the month my contract with my current employer (no, not Hackaday) will end. With the interviews starting to line up I therefore thought it’d be a nice opportunity to design the PCB business card you can see in the picture above.

It is made of two PCBs soldered together, the bottom one containing the SMD components while the top one only has holes to let most of them pass through. The design was mainly inspired by the first version we already featured on Hackaday although the microcontroller was changed for the (costly) ATMega32u4 and the top PCB was slightly milled so the LEDs may shine through the FR4. The LEDs are connected in groups of 2 (total of 8 groups) to PWM channels and a hidden flash memory allows the card to be recognized as an external 2MB storage using the LUFA library. All source files may be downloaded on my website.

Measuring Car Engine RPM via the Cigarette Lighter

delorean

Sometimes we forget how many things we can do with a simple oscilloscope. In this video [Ben] uses one that Tektronix lent him to measure his DeLorean engine RPM. By checking the car main ~12V voltage one may notice that the voltage spikes occurring are directly related to the engine speed, as they are created by the inductive kicks from the ignition coils. Obviously the multiplication you have to do to get the RPMs from the number of spikes per second depends on your engine configuration (flat 4, v6…).

The method that [Ben] used was to search for high amplitude spikes on the (AC coupled) car 12V Fast Fourier Transform (FFT) to get a reliable measurement given the many electrical noise sources present in his car. At the end of his video, he however mentioned that it could still be possible to get a good measurement with a simple voltage comparator and a high enough voltage reference.

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Developed on Hackaday: We Have Final Prototypes!

Mooltipass final prototype

The last few weeks have been quite tense for the Mooltipass team as we were impatiently waiting for our smart cards, cases and front panels to come back from production. Today we received a package from China, so we knew it was the hour of truth. Follow us after the break if you have a good internet connection and want to see more pictures of the final product

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Building a CNC Milling Machine for less than $1300

CNC milling machine

[Mynasru] tipped us about a homemade CNC milling machine that his friend [trochilidesign] recently made. We have to admit it may be one of the best ones we’ve featured so far on Hackaday, mainly due to its elegant design (see picture above) and its all metal structure with linear guide rails. In the very well detailed write-up, we can gather that the CNC machine was designed using SolidWorks.

The main frame is built around 2 Maytec 40x80mm profiles and 2 endplates made from 10mm thick aluminum. 3 Nema 23 stepper motors and their drivers power the build, all of them bought on ebay. Finally, the Mach3 CNC software was chosen to interpret the G code and send the appropriate control signals.

Due to licensing restrictions the original author can only provide us with PDF files detailing each part of the machine, but we’re sure this should already be enough for interested persons out there.

Developed on Hackaday: Front Panels and Beta Testers Program

mooltipass front panel

We’re pretty sure that most of our readers already know it by now, but we’ll tell you anyway: the Hackaday community (writers and readers) is currently developing an offline password keeper, the Mooltipass. As it has been more than two weeks since we wrote an article about our progress, today’s will be about the Mooltipass front panels and our beta testers program.

At the end of our mechanical design rundown article we showed that we were originally planning to put a slightly tinted acrylic panel on top of our device. We however could still make out the Mooltipass’ insides, which wasn’t in line with the nice professional look we wanted. We then designed another front panel, one which was transparent above the OLED screen/LEDs and opaque (black) on top of the rest. To our surprise the result still wasn’t as good as we had hoped, as the contrast between the front panel and the screens/LEDs was too big. We finally came up with the panel shown above (see GitHub repository folder) which combines the two techniques previously described. As it is still in China, we’ll show you the final result when we get it in our hands.

We launched around 10 case prototypes in production, they will soon be shipped to our current contributors/advisers together with the smart cards chosen by Hackaday readers. In the meantime we sent our official call for beta testers to our mailing list recipients and hackaday.io followers, in which we asked them to fill a small form that will allow us to know them a bit better. We asked about their home/work computer setup, their level of expertise, their willingness to contribute to the prototype cost and finally specifics about who would use the Mooltipass they’d receive. We are targeting a broad range of users but also testers that will provide us with detailed feedback and clear bug reports.

We also spent quite a while searching for cheaper alternate parts that could be sourced in relatively big quantities. This is usually an overlooked aspect of a project so we preferred to tackle this as soon as possible. In a few weeks the contributors and I will receive all the components required to assemble our final prototype (front panels / case / top & bottom PCBs / smart cards) and it will be time to write a new update. Want to stay informed? You can join the official Mooltipass Google Group or follow us on Hackaday Projects.

Discovering a Wifi Enabled 10MHz Oscilloscope

 

As most of our readers know, [Mike] was visiting Bay Area Maker Faire  last weekend with a big Jolly Wrencher on his back. During his tour he encountered the neat oscilloscope shown in the video above, made by the Belgian company Velleman. Even though it only has a 10MS/s sampling rate and a 10MHz bandwidth, our guess is that it may still be useful for some hobbyists out there as it can communicate with any PC/smartphone/tablet using its Wifi interface.

Inside the black box is a 3.7V 1800mAh Li-ion battery with a USB port to recharge it or update the oscilloscope’s firmware. As seen in the video, the tablet’s touchscreens may enable more natural interaction with the user interface. The protocol used to export the acquired samples is open, which may allow users to create their own analysis program. The oscilloscope uses an 8 bit analog to digital converter and a 4K samples buffer.

Ask Hackaday: Can Battery-Free Bluetooth Item Locating Tags Exist?

iFind Tag

[Vishak] tipped us about the iFind Kickstarter campaign, a 1.25×1.06×0.09″ (32x27x2.4mm) tag meant to be attached to anything you may lose in your daily life. This device communicates with Bluetooth Low Energy (BLE) enabled smartphones, has a 200ft (60m) detection range and a loud alarm. What is interesting to mention is that this device doesn’t need any battery to operate as it

recycles electromagnetic energy and stores it in a unique power bank.

As you can guess, this particular claim intrigued the Hackaday team given that we never featured so small energy harvesting devices. The ‘closest’ thing that comes to our minds is the Allsee project, a simple gesture recognition device that uses existing wireless signals (TV and RFID transmissions) to extract any movement that occur in front of it. However the antenna was quite big and very little power was extracted.

A quick Google search let us know that Bluetooth Low Energy solutions usually consume an idle current of around 10uA @ ~3V. The (very) successful Sticknfind campaign which promoted the same battery-enabled product claimed a one year autonomy with a CR2016 battery and a 100ft range, leading to a ~90mAh/24/30.5/12 = 10.2uA idle current. As we’re not expert on the subject, we would like to ask our readers if they ever came across such energy harvesting performances (3V*10.2uA = 30uW) in a normal home environment. Our very bad maths indicate that if one would like to extract power from a typical Wifi router located 2 meters from you emitting 0.5Watts of power (in a perfect vacuum environment) with a 32*27mm = 864mm = 0.000864m² tag you’d only be able to get 0.5 * (0.000864/(4*pi*2*2)) = 8.6uW.

It is therefore too bad that we can’t see in the presentation video what is inside the iFind, nor more details about the patent pending technologies involved. We hope that our dear readers will enlighten us in the comments section below.