Digitally Controlled Dual Power Supply

Dual Power Supply

[Kerry] set out to build a digitally controlled dual supply for his bench. He’s already built a supply based on the LM338 linear regulator, but the goal this time was to build it without a linear regulator IC, and add digital control over both the current and voltage.

In part one of the build, [Kerry] explains the analog design of the device. He had an extra heatsink kicking around, which can dissipate enough heat from this linear supply to let it run at 10 A. A NE5532 opamp is used to track a reference voltage, which can be provided by a DAC. The current is measured by a LT6105 shunt sense amplifier, then compared to a reference provided by another DAC.

Part two focuses on the digital components. To interface with the analog circuitry, two MCP4821 DACs are used. These are controlled over SPI by an ATmega328P.

Fortunately, [Kerry] also has his own DC load project to test the supply with.

Internet-Enabling a Lamp with the Raspberry Pi


[Jack] sent in his writeup for internet enabling a home lamp. While we will certainly have some comments saying this is too simple, it does a great job of breaking things down to the basics. For those that aren’t confident in their electronic skills, this is an easy hack to a commercial device that greatly expands it’s capabilities. [Jack] started with a cheap wireless outlet controller. By opening the remote and wiring each switch to a 2N222A transistor, you can very easily control the remote from the GPIO pins on the Raspberry Pi. In [Jack's] case, he set up a web page using Flask that allows quick on/off control.

Of course, this method can be used in any number of instances where you have a wireless controller, from small lamps to garage doors. Given it’s simplicity, anyone can do it with even basic skills. If you’re a beginner who’s been itching to do some home automation, follow [Jack's] writeup and check an item off your todo list!

Xbox One Headset 2.5 mm Plug Adapter

Xbox One internal adapter

In all of Microsoft’s grand wisdom they found it necessary to make the new Xbox One headset adapter without a standard 2.5 mm headset jack. People have invested great amounts of money in quality headsets for previous game platforms that now cannot jack into the Xbox One controllers. This may seem like a déjà vu hack from a week ago but it is different and adds more solutions for the annoying Xbox One headset compatibility problem.

[Jon Senkiw] A.K.A [Xandrel] wasn’t having any of this Microsoft nonsense so he cracked open the headset adapter case that plugs into the Xbox One controller. He photographed the PCB and wiring and realized he could fit a 2.5 mm headset jack from an old donor cellphone into the case. A dap of hot glue, some AWG 30 jumper wires and a bit of plastic trimming was all it took to get a jack inside the headset adapter just the way Microsoft should have done from the factory.

Previously when [octanechicken] added a 2.5 mm female phone adapter at the end of the cable he did not connect the black wire to anything being it was the 2nd side of a push-pull speaker. However, from looking at [Jon’s] photos he connected the speaker output wire to a solder pad on the PCB where the black wire originally connected, marked HPL, and he had nothing connected to the HPR pad. This seemed to work for [Jon] just fine, but is the opposite of what [octanechicken] did last week when he connected the blue wire to the speaker output which would have traced back to the HPR pad on the PCB.

This hack makes these controllers backwards compatible without too much issue being reported. If you have issues please report here or on [Jon’s] SE7ENSINS thread. He has also made comments on the thread that he is willing to help mod headsets, so if you’re not able to hack this yourself [Jon] might be willing to help.

Hidden Reed Switches for DIY Home Security


[Rhys] wanted to secure his home against burglars, but didn’t want to go the normal route of using those bulky plastic magnet and reed switch deals. So he sourced some glass reed switches and made his own completely hidden security system.

By using small glass reed switches [Rhys] was able to mount them flush to the wood paneling just above the window frames. To do this he drilled and then chiseled two slots for the reed switches to go in, with the wires routed into the house. A bit of bondo or drywall filler and some paint later and they are completely invisible! To finish it off he glued small neodymium magnets to the top of the window frame which close the switches. It’s a very clean build and quite inexpensive to do — the possibilities for wiring up your entire home like this are quite tempting!

He’s got the switches installed already… why not couple it all to a complete home security setup? We shared a project last year that does just that!