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Travis Hayes
Worked at Azul Systems
Lives in Madbury, New Hampshire, USA
219 followers|238,832 views
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Travis Hayes

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I'm enjoying +John Wiggins' project postings, and would like to do more of my own.

The picture is a prototype of an isolated DC power supply that should meet the needs of a test and measurement device I'm designing. Such devices often have similar requirements:

1. Power for the analog section needs to be galvanically isolated from main power. This prototype alternates 5 volts across the primary side of a small PCB mount transformer at ~400kHz. The switching is done with a dedicated IC, but I'll do this with an AVR micro and a couple 2N7000 FETs in the final device.

2. Power needs to be dual rail: plus, ground, and minus. The secondary side of the transformer goes into a full wave bridge rectifier and output caps to produce unregulated power at something like +/-6.5V.

3. Power needs to be regulated. The unregulated positive and negative supplies need to stabilized around +/-5V and filtered to remove ripple. Low dropout regulators were required for this case. The unregulated voltages simply didn't have enough headroom beyond the desired +/-5V for classic 7805 and 7905 regulators to function decently.

4. There needs to be an additional higher positive DC voltage to drive power FET gates or voltage references. I do this with a charge pump voltage tripler. The oscillating, pre-rectified ~6.5V from the secondary side of the transformer is fed into a ladder of diodes and capacitors. This is shown on the very right side of the breadboard, with the meter showing 19.17 volts with a 100k resistive load.

This was my first time prototyping a charge pump (voltage tripler) to generate low current, higher voltage DC. This is so cheap and easy to do if there's already a switching supply. It's a nice tool to have in the bag of tricks.
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Travis Hayes

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Please pardon my joyful ululation, but I have received the surprise gift of an ulu!

I've vaguely wanted one ever since I went to Nunavut. This particular form should be quite practical. Thanks so much mom +Barbara Hayes! My vast array of kitchen gear is now complete.
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That has got to be the most awesome way to chop stuff! 
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Low Power Voltage Sampling
The car computer project has taken a big detour for the last few months in lieu of my gaining more experience with microcontrollers and electronics. Carputer 2015 was mostly a system integration design to be achieved by plugging together existing modules. C...
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Because +Cindy Brown says the cool kids are doing it. Gotta collect 'em all.
Create your Visited States Map and show us where you've been!
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I've been in all lower 48 states and every southern province except the Maritimes.
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The one stop light in my town.

There is only a single home on the other side of this active rail line. Access is from a state road, and the tracks and main road curve to allow an overpass not far from here. At the crossing, the foliage and curvature of the tracks affords very little visibility. It all feels a bit wrong.

+Dat Moose​
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There's always one. Get out of the road, you turkey! Don't they even realize what season it is?
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We get families of ducks and geese from the nearby manmade lake blocking traffic on my street. They just saunter across the road, taking their sweet time.

It's like they know they're a protected species and are saying "whaddaya gonna do ... shoot me?"

Bastards.
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Getting Intermediate with Arduino
There's a wealth of information out there on getting started with the Arduino microcontroller, development environment, and basic electronics. So you've interfaced with LEDs, sensors, and modules. You've written sketches to do digital input and output, anal...
There's a wealth of information out there on getting started with the Arduino microcontroller, development environment, and basic electronics. So you've interfaced with LEDs, sensors, and modules. You've written sketches to d...
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Cool! Marked this for future reading.
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Not that I'm biased, but w00t!
Evidence mounts against the traditional story of early human migration through an ice corridor
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Finally. 
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Can a Teensy 3.2 board be used as a quick and dirty function signal generator? All sines point to yes!
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I'm a long time PC gamer, but I bought an Xbox One earlier this year. The idea was to get off the upgrade treadmill and banish Windows from my PC. Adjusting to the coarseness of the controls and viewing distance from the display wasn't easy, so the console mostly languished.

Enter Fallout 4. This game gives me a reason to persevere with the console. I'm getting better with the controls and VATS makes combat reasonable. My aging eyes can actually read the screen text fairly well compared to some games. I've moved my couch forward a bit to help even more.

The crafting, settlement building, and useful scrounging add a lot of enjoyment for OCD me. I used to just collect and sell everything to accumulate mad caps. The game has crashed once so far, which I've learned to expect from the Fallout franchise. Having great fun!
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Awesome. I've actually gone the other way and now have 2 steam machines in my house. Playing fallout 3 on a TV is awesome, especially with a steam controller.
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Something for my metal brothers and sisters. The light was just right as I passed, so I had to stop for a photo.

+Georgi Karavasilev+Brett Legree+Mark Derricutt​
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Carputer 2015 - September Status
Time rolls on and the car computer has yet to roll. I've been having way too much fun interfacing and developing for Arduino. Still, everything else is ready to go, so expect the rolling demo video and blog post sometime next week. Here's a quick summary of...
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+Que Onda always good to hear from someone else who's into this stuff. Yes, this project is still alive! I've just kept digging deeper into the custom electronics and microcontroller side of things because that lets me build anything I want. It's addictive. Thanks for the encouragement to get back to the rolling demo.
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Travis's Collections
Story
Tagline
Identifying the world's problems, designing solutions, implementing nothing.
Introduction
Former Silicon Valley software engineer, now owner of the family farmstead in semi-rural New Hampshire.
Bragging rights
brain in a jar, bad at yard work
Places
Map of the places this user has livedMap of the places this user has livedMap of the places this user has lived
Currently
Madbury, New Hampshire, USA
Previously
Mountain View, California, USA - Sunnyvale, California, USA - Cambridge, Massachusetts, USA - Barrington, New Hampshire, USA
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Other profiles
Work
Employment
  • Azul Systems
    Linux Systems, Appliance, Distro, 2003 - 2012
  • Mpath/HearMe
    Java Server Guru, 1997 - 2001
  • USWeb Utopia
    Web Technologies Developer, 1996 - 1997
  • Cabletron Systems
    Software Developer, 1994 - 1996
Basic Information
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Single
Other names
Travis Converse Hayes
Travis Hayes's +1's are the things they like, agree with, or want to recommend.
WiFi Web Login
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Automatic hotspot login, hotel WiFi login, corporate guest WiFi login, and other Captive Portal Logins. Stop filling in the annoying web log