Slimline USB Charger for tiny ham Radios

The recent trend to smaller and smaller handy talkie (HT) transceivers is approaching the limits of the human interface. Sure, engineers could probably continue shrinking the Baofeng and Wouxun HTs further, but pretty soon they’ll just be too small to operate. And it’s getting to the point where the accessories, particularly the battery charging trays, are getting bulkier than the radios. With that in mind, [Mads Hobye] decided to slim down his backpacking loadout by designing a slimline USB charger for his Baofeng HT.

Lacking an external charging jack but sporting a 3.7 volt battery pack with exposed charging terminals on the rear, [Mads] cleverly capitalized on the belt clip to apply spring tension to a laser-cut acrylic plate. A pair of bolts makes contact with the charging terminals on the battery pack, and the attached USB cable allows him to connect to an off-the-shelf 3.7 volt LiPo USB charger, easy to come by in multicopter circles. YMMV – the Baofeng UV-5R dual-band HT sitting on my desk has a 7.4 volt battery pack, so I’d have to make some adjustments. But you have to applaud the simplicity of the build and its packability relative to the OEM charging setup.

This isn’t the first time we’ve seen [Mads] on Hackaday. He and the FabLab RUC crew were recently featured with their open-source robotic arm.

Crack Open a USB Car Charger to make it a Variable DC-DC Converter

[Boolean90] hacked a cheap USB car charger into a variable power supply. His proof of concept is to use this as a variable-speed motor controller. The best part is that nothing is being abused, the regulator inside is still running within manufacturer’s spec.

While we’ve seen similar hacks before, [Boolean90]s video is pretty cool and provides a nice insight into the components used in these cheap devices. Rather than a linear regulator, which would dissipate too much heat the device uses a common jelybean MC34063A (PDF) switching DC-DC converter which costs about 10 cents on eBay (about two dollars for twenty, shipped). Here it’s used to step the car batteries 12 volts down to 5, but can also be used in step-up and inverting configurations.

Like all switching buck converters the MC34063A uses a PWM (pulse width modulated) signal to drive an inductor and capacitor, which effectively form an LC filter. By controlling the pulse width, the output voltage can be regulated. [Afrotechmods] has a great tutorial on the basic principle. The regulation is controlled by feedback resistors. [Boolean90] simply added a variable resistor to allow the output voltage to be controlled.

Neat hack [Boolean90]! Continue reading “Crack Open a USB Car Charger to make it a Variable DC-DC Converter”

Insane 33 Port USB charger

Like it or not, Hackers gonna hack. And when your hackerspace has someone who looks like Doc Brown from Back to the Future, the builds can get a bit weird, like this Hack42 FestivalCharger.

The Hack42 hackerspace in Arnhem, The Netherlands had collected a large number of TP-Link 5V USB chargers – but all of them had the North American NEMA plug (flat, 2 pin) which wouldn’t fit the Schuko sockets prevalent in The Netherlands. [Simon “MacSimski” Claessen] decided to whip out his giant soldering iron and use it to solder two long pieces of welding filler metal rods to 33 of the chargers, effectively wiring them up in parallel. He did apply his obvious skill and experience to good use. For one, the diameter of the filler metal rods he used were just about the right size to fit in the Shucko Schuko socket. And the gap between the two turned out to be the right distance too, thus creating a sort of Schucko Schuko plug. All that was needed to power up all the chargers was to connect a socket extension to the FestivalCharger. The unit was built to allow crowds of festival-goers to charge their phones and battery-powered gadgets simultaneously. To make sure the visitors didn’t get electrocuted, he used a piece of PVC pipe to cover up the exposed pins and keep it all safe.

Thanks to Hack42 member [Dennis van Zuijlekom] for sending in this tip.

Keystroke Sniffer Hides as a Wall Wart, is Scary

For those of us who worry about the security of our wireless devices, every now and then something comes along that scares even the already-paranoid. The latest is a device from [Samy] that is able to log the keystrokes from Microsoft keyboards by sniffing and decrypting the RF signals used in the keyboard’s wireless protocol. Oh, and the entire device is camouflaged as a USB wall wart-style power adapter.

The device is made possible by an Arduino or Teensy hooked up to an NRF24L01+ 2.4GHz RF chip that does the sniffing. Once the firmware for the Arduino is loaded, the two chips plus a USB charging circuit (for charging USB devices and maintaining the camouflage) are stuffed with a lithium battery into a plastic shell from a larger USB charger. The options for retrieving the sniffed data are either an SPI Serial Flash chip or a GSM module for sending the data automatically via SMS.

The scary thing here isn’t so much that this device exists, but that encryption for Microsoft keyboards was less than stellar and provides little more than a false sense of security. This also serves as a wake-up call that the things we don’t even give a passing glance at might be exactly where a less-honorable person might look to exploit whatever information they can get their hands on. Continue past the break for a video of this device in action, and be sure to check out the project in more detail, including source code and schematics, on [Samy]’s webpage.

Thanks to [Juddy] for the tip!

Continue reading “Keystroke Sniffer Hides as a Wall Wart, is Scary”

Backseat USB Charger


Whether you’re relegated to the backseat of your ride or just strapped for access to power, you may benefit from adding your own backseat USB charger. While this is a fairly straightforward hack, we’re surprised at how clean it turned out and at the convenience it provides.

[wongman2001] started by grabbing a socket wrench and unbolting his seat from the rails in the floor. He then disconnected the electrical plugs for the chair’s heating and power seat adjustment. With the chair disconnected and removed from the car, [wongman2001] further dissected its components, removing its back panel and test fitting a female cigarette adapter. Though this seat had plenty of room near the headrest, you may need to carve out some foam for a snug fit in your vehicle. To source the needed 12V, [wongman2001] tapped into the wiring for the seat’s motor, then soldered and insulated the connections to the cigarette lighter jack.

Check out some other clean-looking car hacks like the hidden MP3/USB Aux hack or the Nexus 7 double-DIN dashboard hack.

Getting rid of a tangled web of phone chargers


Every night, [Roberto]’s kitchen counter is cluttered with three cell phones, three different cell phone chargers and a mess of wires until morning comes and the chargers are moved to a drawer for the following night. For [Roberto] this is a bit of a pain – a much easier solution would be to have a few USB ports embedded right into his kitchen backsplash. With the right tools, this can be easily done, resulting in a very professional looking installation for charging a trio of phones.

After removing a Euro AC outlet and replacing it with three iPhone chargers, [Roberto] simply soldered the six mains connections on the chargers to his house’s wiring. This resulted in a perfectly functional but rather ugly home project, though.

The next step was to machine a blank AC outlet cover for the three USB ports. [Roberto]’s CNC mill made quick work of this piece of plastic and turned it into a professional-looking installation.

Solar backpack ipod/usb charger

Jason sent me his solar ipod charger how-to. The regulator may not be neccesary – but there are so many models, I don’t know if the new Nano’s hold up to the old power input standard. He put a 7805 regulator on a 6v 100ma flexible panel that he mounted on his backpack. I’ve seen this sort of thing on a shuffle before, but this one should work for most iPods. USB power management sometimes shoots itself in the foot, but iPods are willing to pull power if it’s not present. It’s nice, clean and simple. I’d consider adding some high temp hot glue (or epoxy)to keep the soldered connections from breaking.