Dub Siren, a 555-powered synthesizer

Classic Chip Line-Up Powers This Fun Dub Siren Synth

There’s a certain elite set of chips that fall into the “cold, dead hands” category, and they tend to be parts that have proven their worth over decades, not years. Chief among these is the ubiquitous 555 timer chip, which nearly 50 years after its release still finds its way into the strangest places. Add in other silicon stalwarts like the 741 op-amp and the LM386 audio amp, and you’ve got a Hall of Fame lineup for almost any project.

That’s exactly the complement of chips that powers this fun little dub siren. As [lonesoulsurfer] explains, dub sirens started out as actual sirens from police cars and the like that were used as part of musical performances. The ear-splitting versions were eventually replaced with sampled or synthesized siren effects for recording studio and DJ use, which leads us to the current project. The video below starts with a demo, and it’s hard to believe that the diversity of sounds this box produces comes from just a pair of 555s coupled by a 741 buffer. Five pots on the main PCB control the effects, while a second commercial reverb module — modified to support echo effects too — adds depth and presence. I built-in speaker and a nice-looking wood enclosure complete the build, which honestly sounds better than any 555-based synth has a right to.

Interested in more about the chips behind this build? We’ve talked about the 555 and how it came to be, taken a look inside the 741, and gotten a lesson in LM386 loyalty.

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Motorized Inline Skates Run On Makita Power

Inline skates can be fun, but like most wheeled contraptions, they’re even better when motorized. With just such a goal in mind, [The Real Life Guys] decided to whip up a set of powered skates, running on Makita power!

To get power to the ground, the third wheel on each skate is modified to have a sprocket attached. A Makita drill is then fitted to the skate, transferring power to the wheel through a 90-degree gearbox and a chain drive. The drill is controlled by removing the trigger from the shell and hooking it up with an extended cable.

It’s a lairy setup that probably takes serious practice to use effectively, but does allow for fancy tricks like differential steering if you really want to show off. It’s a great example of using a powerdrill as an all-inclusive motion setup, with the battery, motor and drivetrain already integrated in a neat, tidy package. It’s not the first time we’ve seen a powered set of ‘skates, either! Video after the break.

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Light Dimmer Shows How To Steal Power From AC Line

We see a lot of traffic on the tips line with projects that cover old ground but do so in an instructive way, giving us insight into the basics of electronics. Sure, commercial versions of this IR-controlled light dimmer have been available for decades. But seeing how one works might just help you design your Next Big Thing.

Like many electronic controls, the previous version of this hack required a connection to a neutral in addition to the hot. This version of the circuit relies on passing a small current through the light bulb the dimmer controls to avoid that extra connection. This design limits application to resistive loads like incandescent bulbs. But it’s still a cool circuit, and [Muris] goes into great detail explaining how it works.

We think the neatest bit is the power supply that actually shorts itself out to turn on the load. A PIC controls a triac connected across the supply by monitoring power line zero-crossing. The PIC controls dimming by delaying the time the triac fires, which trims the peaks off of the AC waveform. The PIC is powered by a large capacitor while the triac is conducting, preventing it from resetting until the circuit can start stealing power again. Pretty clever stuff, and a nice PCB design to boot.

Given the pace of technological and cultural change, it might be that [Muris]’ dimmer is already largely obsolete since it won’t work with CFLs or LEDs. But we can see other applications for non-switched mode transformerless power supplies. And then again, we reported on [Muris]’s original dimmer back in 2009, so the basic design has staying power.

This Quick Hack Will Keep You Online During Your Next Power Outage

The modern human’s worst nightmare: a power outage. Left without cat memes, Netflix, and — of course — Hackaday, there’s little to do except participate in the temporary anarchy that occurs when left without internet access. Lamenting over expensive and bulky uninterruptible power supplies, Youtube user [Gadget Addict] hacked together a UPS power bank that might just stave off the collapse of order in your household.

This simple and functional hack really amounts to snipping the end off of a USB  power cable. The cable is then attached to a screw terminal to barrel connector adapter and plugged it into a pass-through power USB power bank. No, really — that’s all there is to it. [Gadget Addict] notes that while most modems and routers are designed to run off a 12V power supply, they still operate at 5V. He goes on to connect several router and router/modem combination units to the power bank. In each case the system appears to boot up and perform normally.

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Pi-Powered Anti-Cat Trap Soaks Felines And Other Animals

[Joshua] has a problem with cats. They like pooping in his garden. He decided to take action with this awesome automated and humane cat trap.

Now just to clarify, he did attempt a few other alternatives before going all out in cat defense – the easiest solution would be to get a cat of his own, but alas, he’s not a cat person.

The system uses a Raspberry Pi in a waterproofed housing with a PiCam. He’s written some rudimentary code to make use of the PiCam Python Library which also allows him to record pre-cat-trapping footage, much for our enjoyment. When motion is sensed, the Pi trips a 24VAC solenoid water valve, which turns on the sprinkler and quickly soaks the intruder.

Stick around after the break for quite a few videos catching the furry little buggers in the act!

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Recliner Sofa Given The Power Of The Pi

pi-sofa

If you go to buy a sofa these days you’ll not only be greeted with the option of one or more reclining positions, but a fully modern unit comes with motorized reclining. That simply wasn’t convenient enough for [Nicki] and [Kevin] who wanted to control the feature from a smartphone rather than a physical interface (buttons) on the side of the furniture. What resulted is the PiSofa, a Raspberry Pi connected to the furniture’s electronics with the help of a relay board.

This is most certainly a hack, but no doubt one with a lot of finesse. Check out that white PCB. That’s right, it’s a factory spun board to keep things nice and neat. They went with one of our favorite tricks by housing everything inside of a food storage container. After some Ruby coding the Pi now has complete control of the sofa. We’re not overstating this. It literally is the only way to control it because the original buttons no longer work. But that’s okay, turns out not only does it work with their smartphones, but with a [Kevin’s] Pebble watch as well.

We can’t think of any past hacks that specifically targeted the couch. But here’s a hammock that you can drive down the street.

Black Hat 2009: Powerline And Optical Keysniffing

sniff

The 2009 edition of the Black Hat security conference in Las Vegas has just begun. The first interesting talk we saw was [Andrea Barisani] and [Daniele Bianco]’s Sniff Keystrokes With Lasers/Voltmeters. They presented two methods for Tempest style eavesdropping of keyboards.

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