All posts by Jeff

Electrical engineer, tinkerer, maker.

Design and Construction of a 24 GHz Low Noise Amplifier

October 26, 2013 Jeff 2 Comments

Tony Long and I designed and built a 24 GHz low noise amplifier for our ECE192 undergraduate independent study project at UCSD.

The amplifier was designed with an early version of Agilent ADS, PCBs were fabricated on Rogers 5880 (Duroid), and we hand built several prototypes on K-connector fixtures that Tony designed. Measured results were consistent with our simulations.

Closeup of two stage LNA PCB

Tony and I won an award for this project at the Eureka! undergraduate research conference in June 2000.

I heard recently that this project is being used as an example of a good EE senior design project at other universities, so I dug up an original copy of the paper we submitted and posted a PDF here.

Events

Open Hardware Summit Pics!

September 8, 2013 Jeff Leave a comment

What an awesome event. Great people, great talks, and gorgeous weather made for an epic weekend in Cambridge.

My photos are up on flickr.

Also, I just finished recording a shiny new episode of The Amp Hour, which should be online ~~as soon as Chris finishes editing. Look for it later tonight or tomorrow~~ on Tuesday.

Events

Upcoming events: OHS, TAPR DCC, NYMF

September 1, 2013 Jeff Leave a comment

OSHW summit goodie bag photo credit: adafruit[/caption]

There are three major events of interest to open source hardware and makery folks this month:

The Open Hardware Summit is this Friday (9/6) in Cambridge, MA. I’ll be there with Chris Gammell of the Amp Hour. Tickets are still available.
The 32nd annual Tucson Amateur Packet Radio (TAPR) Digital Communications Conference takes place in Seattle on September 20-22nd.
The World Maker Faire New York takes place on the same weekend, September 21-22nd, in Queens, NY.

I’ll be at OHS and TAPR, but have to skip the NY Maker Faire this year. I imagine that far fewer folks from OHS will be attending NYMF now that those events are no longer co-located.

Sorry NYMF, but I can’t turn down an excuse to visit my friends in Harvard square.

Electronics, Microcontrollers

Hexbright Hacking 2 – Bedazzled

August 31, 2013 Jeff Leave a comment

I borrowed a few lines of code from the hexbright dazzle demo to create a new bedazzled version of my custom firmware. The dazzle mode is activated by holding down the push button for more than 500 ms at power on.

Also of interest:

Check out this incredibly detailed development log / data compendium on the Hexbright.
David Hilton’s Hexbright library on Github

Electronics, Microcontrollers, Projects

Hexbright Hacking

August 24, 2013 Jeff 2 Comments

The Hexbright is an Arduino-compatible open source flashlight that was the subject of a very successful kickstarter campaign in 2011.

Today I spent a short time working on some custom firmware for it.

My firmware adds two new features:

Button presses cycle between modes (low, med, high brightness) as usual, but if you wait longer than CYCLE_DELAY (default 5 seconds) between presses, the next press turns the hexbright off.
If the hexbright is left on for longer than AUTO_OFF_MINUTES (defaults to an hour), the hexbright turns off. Handy for when you prop the light somewhere and forget about it.

You can download my custom Hexbright Arduino sketch here. If you’re new to the Hexbright, read these well-written instructions first. You’ll need to install the required USB driver and Arduino board configuration file.

Amazon link: HexBright FLEX, 500 Lumen Programmable LED Flashlight

MightyOhm