Build Yourself An Awesome Modular Power Supply

February 6, 2016 by Elliot Williams 34 Comments

You may think you’ve built a power supply for your bench. Heck, we all do. But until you check out [Denis]’s bench power supply build, you may not even know what you’re missing.

[Denis]’s design is nearly entirely modular and targeted to the intermediate builder. It’s built on easily available parts and through-hole components. It’s got an Arduino running as the brains, so you’re going to be able to hack on the code when you feel like tweaking it. But easy doesn’t mean light on features. Let’s walk through the build together.

It starts off with a pre-regulator: a switching MOSFET that gets the voltage down to just a couple volts above the target value. Then it’s off to the post-regulator that includes all of the fine adjustments, the DAC and ADC interfacing to the microcontroller, and some fancy features like a “down-programmer” that turns the output off extra quickly.

On the user end of things, [Denis] made a very sleek board that incorporates a TFT touchscreen for the controls, Arduino connections, and the obligatory banana plug outputs. There’s opto-isolation on the SPI bus, a real-time clock, and a bunch more goodies on board. He’s in his third revision of this module, and that level of refinement shows. It’s even SCPI compliant, meaning you can control remotely using an industry-standard protocol.

So what would you do with a ridiculously fancy power supply under microcontroller control? Test out battery charging algorithms? Program test routines to see how your devices will work as their batteries drain out? We have no idea, but we know we want one!

Hacklet 94 – Pi Zero Contest Entries

February 6, 2016 by Adam Fabio 16 Comments

Hackaday and Adafruit have joined forces to present the Raspberry Pi Zero Contest. A great contest is nothing without entries though. This is where the Hackaday.io community is proving once again that they’re the best in the world. The contest is less than a week old, yet as of this Thursday evening, we’re already up to 33 entrants! You should submit your own project ideas now for a chance at one of the many prizes. This week on The Hacklet, we’re going to take a look at a few of these early entrants!

We start with [usedbytes] and Zero Entertainment System [usedbytes] has crammed an entire emulator into a classic Nintendo Entertainment System control pad thanks to the Raspberry Pi Zero. Zero Entertainment System also has something the original NES couldn’t dream of having: An HDMI output. The emulator uses the popular RetroPie front end. We’re happy to say that [usedbytes] knew that hacking up a real Nintendo controller would be sacrilegious, so they grabbed a low-cost USB clone from the far East. A bit of creative parts-stuffing and point-to-point wiring later, ZES was ready to meet the world!

Next up is [Jenny List] with The Australia Project. [Jenny] is a hacker from Europe. She’s hoping to use a Pi Zero to talk to Australia. “Talk” may be pushing it a bit though. The Australia Project will use the Weak Signal Propagation Reporter (WSPR) network to transmit RF straight out of the Pi’s GPIO ports. All that is required is a good filter, an antenna, and a balun. The filter in this case is a 7-pole Chebyshev low-pass filter. The filter keeps the Pi’s harmonic filled square waves from messing up every band from DC to light. [Jenny] normally sells these filters as a kit, but she’s made a special version specifically for the Pi Zero.

[Radomir Dopieralski] has brought his signature walking robots to the Pi Zero world with Tote Zero. Tote Zero is a quadruped walking robot built mainly from 9 gram servos. [Radomir’s] custom tote board interfaces the servos to the Pi Zero itself. The Pi Zero opens all sorts of doors for sensors, vision, and advanced processing. The Arduino board on the original Tote would have been hard pressed to pull that off. Tote is programmed in Python, which will make the code quick and easy to develop. Tote Zero just took its first steps a few days ago, so follow along as a new robot is born!

Finally we have [julien] with PoEPi: Pi Zero Power over Ethernet with PHY. The Raspberry Pi Zero is so tiny, that it’s easy to forget it needs a fair amount of power to run. [Julien] is giving us a way to connect our Pi to a network while ditching the USB power supply using Power Over Ethernet (PoE). PoE has been powering devices like IP cameras for years now. It’s become a standard way of transmitting power and data. For the Ethernet physical interface, [Julien] is using Microchip’s ENC28J60, which has a handy SPI interface. Linux already has drivers in place for the device, so it’s a slam dunk. The “power” part of this system comes with the help of an LTC4267 PoE interface chip, which has a built-in switching regulator.

If you want to see more entrants to Hackaday and Adafruit’s Pi Zero contest, check out the submissions list! If you don’t see your project on that list, you don’t even have to contact me, just submit it to the Pi Zero Contest! That’s it for this week’s Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Learn Bluetooth Or Die Tryin

February 6, 2016 by Elliot Williams 5 Comments

Implementing a Bluetooth Low Energy (BLE) device from scratch can be a daunting task. If you’re looking for an incredibly detailed walkthrough of developing a BLE project from essentially the ground up, you’ve now got a lot of reading to do: [Jocelyn Masserot] takes you through all the steps using the ARM-Cortex-M0-plus-BLE nRF51822 chip.

The blog does what blogs do: stacks up in reverse-chronological order. So it’s best that you roll on down to the first post at the bottom and start there. [Jocelyn] walks you through everything from setting up the ARM compiler toolchain through building up a linker script, blinking an LED, flashing the chip, and finally to advertising your device to your cell phone. It’s a lot of detail, but if you’re doing something like this yourself, you’re sure to appreciate it.

Of course, all the code is available for you to ~~crib~~ peruse on [Jocelyn]’s GitHub. And for yet more background reading on BLE, check out the Hackaday Dictionary.

New Angle On Raspberry Pi Zero Hub

February 6, 2016 by Rud Merriam 48 Comments

Collectively, the Hackaday readers sigh, “Not another Pi Zero hub!!!”. But [Sean Hodgins’] hub is different. It has a new angle, literally. Besides, it’s an entry in the Hackaday and Adafruit Pi Zero Contest .

[Sean Hodgins’] acute approach is orthogonal to most of the other hubs we’ve seen. He’s mating the hub at right angles to the Zero. The hub plugs into both the on-the-go USB port and the USB power port. No extra cables or wiring needed. [Sean] plans to release the design on GitHub after his Kickstarter campaign ends. He’s supplying bare boards for those who like the smell of solder paste.

This project nicely triangulates the issues of adding a hub to the Zero. The physical connection is solid with the boards connecting via the USB connectors. Power is supplied through the hub the way the Pi expects, which means all the protections the Pi Foundation built into the onboard conditioning are left in place. This also reduces surge problems that might occur when back powering through a hub and hot swapping USB devices. Another neat feature is the notched corner leaving the HDMI port accessible. Similarly, the Pi’s GPIO pins are free of encumbrance. One drawback is the hub is fused at 2 amps, just like the Pi. It would be nice to have a little more headroom for power hungry USB devices. Maybe another 0.5 amp to allow for the Zero’s usage.

[Sean] snaps the two together after the break.

Continue reading “New Angle On Raspberry Pi Zero Hub” →

A DOS Education In Your Browser

February 5, 2016 by Al Williams 32 Comments

In the 1970s and 1980s, a lot of us learned to program using good old-fashioned BASIC on machines ranging from Altairs, Commodores, Apple IIs, and the like. Sometime in the 80’s the IBM PC running MSDOS because the de facto standard, but it was still easy enough to launch BASIC and write a simple little program. Of course, there were other programs, some serious like C compilers, some semi-serious like flight simulators, and some pure fun like Wolfenstein 3D.

If you read Hackaday, you’ve probably noticed that a lot of people emulate old computers–including old MSDOS PCs–using a variety of techniques, including Raspberry PI boards running DOSBox or another emulator. Honestly, though, that’s a lot of effort just to run some old software, right? You can load up DOS emulators on your desktop too. That’s a little easier, but you still have to find software. But if you are as lazy as we are, you might want to check out the MSDOS collection at archive.org.

Continue reading “A DOS Education In Your Browser” →

Very, Very Low Power Consumption

February 5, 2016 by Brian Benchoff 27 Comments

We’re pretty far away from a world full of wall-warts at this point, and the default power supply for your consumer electronics is either a microUSB cable or lithium batteries. USB ports are ubiquitous enough, and lithium cells hold enough power that these devices can work for a very long time.

USB devices are common, and batteries are good enough for most devices, not all of them. There is still a niche where& extremely long battery lifetimes are needed and tapping into mains power is impractical. Think smoke detectors and security systems here. How do power supplies work for these devices? In one of the most recent TI application notes, TI showed off their extremely low power microcontrollers with a motion detector that runs for ten years with a standard coin cell battery. This is one of those small engineering marvels that comes by every few years, astonishing us for a few minutes, and then becomes par for the course a few years down the road.

The first thing anyone should think about when designing a battery-powered device that lasts for years is battery self-discharge. You’re not going to run a battery-powered device for ten years with a AA cell; the shelf life for an Energizer AA cell is just 10 years. Add in a few nanoAmps of drain, and you’ll be lucky to make it to 2020. The difference here is a CR2032 lithium-ion coin cell. Look at the datasheet for one of these cells, and they can easily sit on a shelf for 10 years, with 90% of the rated capacity remaining.

With the correct battery in the device, you’ll need a microcontroller that runs at a sufficiently low power for it to be useful in the mid-2020s. The product for this is the CC1310, a very, very low power ARM Cortex-M3 and sub 1GHz transmitter in one package.

Once that’s settled, it’s simply a matter of putting a sensor on the board – in this case a PIR sensor – and a few analog bits triggering an interrupt occasionally. Have the microcontroller in sleep mode most of the time, and that’s how you get a low-power device with a battery that will last a decade.

A Geek’s Revenge For Loud Neighbors

February 5, 2016 by Brian Benchoff 124 Comments

It seems [Kevin] has particularly bad luck with neighbors. His first apartment had upstairs neighbors who were apparently a dance troupe specializing in tap. His second apartment was a town house, which had a TV mounted on the opposite wall blaring American Idol with someone singing along very loudly. The people next to [Kevin]’s third apartment liked music, usually with a lot of bass, and frequently at seven in the morning. This happened every day until [Kevin] found a solution (Patreon, but only people who have adblock disabled may complain).

In a hangover-induced rage that began with thumping bass at 7AM on a Sunday, [Kevin] tore through his box of electronic scrap for every capacitor and inductor in his collection. An EMP was the only way to find any amount of peace in his life, and the electronics in his own apartment would be sacrificed for the greater good. In his fury, [Kevin] saw a Yaesu handheld radio sitting on his desk. Maybe, just maybe, if he pressed the transmit button on the right frequency, the speakers would click. The results turned out even better than expected.

With a car mount antenna pointed directly at the neighbor’s stereo, [Kevin] could transmit on a specific, obscure frequency and silence the speakers. How? At seven in the morning on a Sunday, you don’t ask questions. That’s a matter for when you tell everyone on the Internet.

Needless to say, using a radio to kill your neighbor’s electronics is illegal, and it might be a good idea for [Kevin] to take any references to this escapade off of the Internet. It would be an even better idea to not put his call sign online in the future.

That said, this is a wonderful tale of revenge. It’s not an uncommon occurrence, either. Wikihow, Yahoo Answers and Quora – the web pages ‘normies’ use for the questions troubling their soul – are sometimes unbelievably literate when it comes to unintentional electromagnetic interference, and some of the answers correctly point out grounding a stereo and putting a few ferrite beads on the speaker cables is the way to go. Getting this answer relies entirely on asking the right question, something I suspect 90% of the population is completely incapable of doing.

While [Kevin]’s tale is a grin-inducing two-minute read, You shouldn’t, under any circumstances, do anything like this. Polluting the airwaves is much worse than polluting your neighbor’s eardrums; one of them violates municipal noise codes and another is breaking federal law. It’s a good story, but don’t do it yourself.

Editor’s Note: Soon after publishing our article [Kevin] took down his post and sent us an email. He realized that what he had done wasn’t a good idea. People make mistakes and sometimes do things without thinking. But talking about why this was a bad idea is one way to help educate more people about responsible behavior. Knowing you shouldn’t do something even though you know how is one paving stone on the path to wisdom.
–Mike Szczys