Machine Shop Soaps Are Good, Clean Learning Fun

At first glance, it’s easy to dismiss the creation of custom bath soaps as far outside the usual Hackaday subject matter, and we fully expect a torrent of “not a hack” derision in the comments. But to be able to build something from nothing, a hacker needs to be able to learn something from nothing, and there is plenty to learn from this hack.

On the face of it, [Gord] is just making kitschy custom bath soaps for branding and promotion. Cool soaps, to be sure, and the drop or two of motor oil and cutting fluid added to each batch give them a little machine shop flair. [Gord] experimented with different dyes and additives over multiple batches to come up with a soap that looked like machined aluminum; it turns out, though, that adding actual aluminum to a mixture containing lye is not a good idea. Inadvertent chemical reactions excepted, [Gord]’s soaps and custom wrappers came out great.

So where’s the hack? In stepping way outside his comfort zone of machining and metalwork, [Gord] exposed himself to new materials, new techniques, and new failure modes. He taught himself the basics of mold making and casting, how to deal with ultra-soft materials, the chemistry of the soap-making process, working out packaging and labeling issues, and how to deal with the problems that come from scaling up from prototype to production. It may have been “just soap”, but hacks favor the prepared mind.

Birthday Celebrations The Pi Way

The William Gates Building concourse packed with Pi enthusiasts
The William Gates Building concourse packed with Pi enthusiasts

On a damp and cold Saturday in early March the Cambridge University Computer Laboratory threw open its doors to the Raspberry Pi community. The previous Monday had been the fourth (or first, if you are a leap year pedant!) birthday of the little single-board computer, and last weekend saw its official birthday celebration.

The festivities took the form of an exhibition floor with both traders and community show-and-tell exhibits, plus a packed schedule of workshops and talks. With the Raspberry Pi 3 launch only a few days before there were no surprise announcements of exciting new hardware, but it did provide a good networking opportunity for the Pi community and a chance to test the state of the Raspberry Pi nation.

The most obvious first impression at the event was that it was one that catered for a diverse range of ages and ability groups. Side-by-side with parents and their children were educators, and the maker community. The range of exhibits was therefore slanted somewhat towards a younger age range with games and interactive exhibits, and there was more than a slight educational flavour to the event. This was entirely in keeping with the Foundation’s objectives, and since it is events like these that are inspiring the Hackaday readers of the next decade, a very welcome sight. Join us after the break for a look at all that was happening at the event.

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Designing A Crystal Ladder Bandpass Filter

Most hobbyists use crystals as an external clock signal for a microcontroller. A less common use would be to make a bandpass filter (BPF) for an RF signal. [Dan Watson] explains his crystal ladder design on his blog and links to several sources for understanding the theory and creating your own crystal ladder band pass filter. If you want a set of these purple PCBs you can order them straight from the purple fab.

crystalfilterschematic
[Dan]’s schematic
One of the sources that [Dan] cites is [Larry Benko]’s personal site which is primarily dedicated to amateur radio projects. Which you can find much more in-depth information regarding the design of a xtal BPF. [Larry] goes into detail about the software he uses and some of the applications of crystal ladder filters.

BPF designed by [Larry]
BPF designed by [Larry]
The process includes measuring individual xtals to determine which ones will work together for your target frequency. [Larry] also walks you through the software simulation process using LTSpice. If you aren’t familiar with Spice simulation you can get caught up by checking out the series of Spice articles by our very own [Al Williams].

Thanks to Dangerous Prototypes for the tip.

Upcycle Old Speakers With C.H.I.P.

Sometimes you get a piece of hardware that’s so cool you can’t help but fix it back up. There are a lot of companies after that sweet, sweet Raspberry Pi money, and the $9 US Dollar C.H.I.P. is a very interesting contender for the space. We have been especially enjoying the stream of neat hacks and example projects they’ve been putting out.

In this case, [Peter] wanted to get a pair of walnut speakers up to modern standards. Already suffering from a glut of audio equipment in his personal space, he decided to sweeten the deal by adding support for his library of music.

The first step was ordering a new set of drivers to replace the aged 40-year-old ones occupying the set. After he got them installed, he added C.H.I.P., a power supply, an amplifier, and a 500GB hard-drive. The controlling software behind the installation is the venerable mpd. This way he can control the speakers from any device in his house as long as he had an interface installed for the daemon.

We’re glad these speakers didn’t end up in the garbage behind a goodwill somewhere, and they do look good.

How Many LEDs Are Too Many?

“Should you answer a rhetorical question?” But anyway, the answer is that you can never have enough LEDs. At least that’s what [Adam Haile] at maniacallabs seems to think. So far, he’s up to 3,072.

We’ve reported on a previous big-LED build of [Adam]’s before, called the “Colossus”. And while this current display is physically smaller, it’s got a lot more LEDs. And that means a lot more, well, everything else. Weighing in at roughly 500W when full-on, with 175-part 3D printed frame and diffuser elements and driven by three Teensy 3.2 microcontrollers driving shift registers, this display is capable of putting out 60 frames per second of blinding RGB LED goodness.

The designs, adapter boards, and animation code will be posted once they’ve “had a chance to clean things up a little”. Here’s hoping that’s soon! [Edit: Code and designs are here. Thanks Adam!]

If you’re in the greater Washington DC area, you can even swing by the NoVA Maker Faire in Reston to check it out in person. If you do, tell ’em Hackaday sent you.

Continue reading “How Many LEDs Are Too Many?”

Wifi Enabled Center Speaker

[Ronald] has been improving his audio set-up for a while now, his latest revision culminating in this WiFi enabled center channel speaker. It all started with feature creep as you can see in this direct quote, “Being an engineer, I couldn’t stop here, not now that I had a way of adding more features…”

He had purchased a new amplifier for his system, but was irritated that the loudness setting would re-enable itself every time he switched inputs. First he thought he might just have a little board that intercepted the signals from his remote and tacked on the loudness off signal. It occurred to him that it would be even cooler if he could control it from his computer or phone. So he opened the case on his new amp and discovered an i2c break-out. We can guess how it went after that.

In version 2.0 he kept most of his work from 1.0, but wanted to simplify the set-up and build it all into a center speaker unit since an amplifier and two speaker cabinets takes up too much room. He fit a similar set-up as before in the center speaker casing, but added a touch screen and a few other improvements.  Though, strangely, he ran into some problems upgrading to the Raspberry Pi 2.0 and had to revert.

The final result is very nice, though obviously not done. As the engineer’s mantra goes, “If it ain’t broke, it doesn’t have enough features yet.”

Telegram Your Devices

[Erhan] has been playing around with the Telegram instant messaging service. Initially, he worked out how to turn on and off LEDs from his cell phone: he sent commands from the phone through the Telegram bot API, to a computer that’s connected over serial to an MSP430 board that actually controlled the LEDs.

But that’s a little bit complicated. Better to cut out the middleman (err…microcontroller) and implement the Telegram reception and LED blinking on a Raspberry Pi. For a project that’s already using a Pi, using the instant messaging service’s resources is a very simple way to interface to a cellphone.

The code for both the standalone RPi project and the MSP430-based microcontroller application are available at [Erhan]’s GitHub. You’re going to be installing Node.js for their telegram-bot-api and jumping through the usual OAuth hoops to get your bot registered with Telegram. But once you’ve done that all on the Raspberry Pi (or target computer of your choice) it’s all just a few lines of fairly high-level code.

We’ve only seen one other Telegram application on Hackaday.io and we’re wondering why. It looks pretty slick, and with the bot’s ability to send a custom “keyboard” to the phone along with the message, it could make cell-phone-based control interfaces a cinch. Anyone else using Telegram for bots?