This weekend I am attending the European hacker conference Hacking at Random. HAR takes place every four years at a former socialist youth-camp about an hour away from Amsterdam in the beautiful Netherlands.
Rather than fly directly to HAR, my wife and I decided to make a larger vacation out of our trip, and we have been busy touring Europe for over a week now. We still have over a week left, so expect slow updates until I return and have a chance to catch up!
David Nichols made this awesome wireless twitter display by combining a hacked Asus WL-520gU wireless router with a Sparkfun serial-enabled LCD display. The router is running the same OpenWrt distribution I used for my Wifi Radio project, plus a USB thumbdrive that provides some additional flash storage space. I really like the custom laser cut base that holds the LCD display and the router!
For more pics and info, check out David’s flickr set for the project.
via Make: Online – Tweetster – Wireless tweets display
Wow! I can’t believe it’s been a year!
Based on the date of my first post, last Wednesday marked the one year anniversary of my blog.
While I pour a toast, here are a few highlights of the past year:
The first project I documented on the site, my solder paste fridge was the end result of a weekend effort to turn an old beer chest into a PID-controlled Peltier cooler for storing tubes of solder paste. A year later, the cooler has a permanent home under my workbench and is still going strong, keeping its contents at a chilly 36 degrees F. Besides solder paste, I keep my POR-15 rust proofing epoxy paint
I needed an excuse to learn assembly language programming on the PIC, and this project fit the bill perfectly. Instead of slogging through yet another PIC tutorial I decided to “just do it” and the video above shows the result. One of my favorite projects of last year, I have plans to build more of these and make some electronic artwork for the lab.
One aging bluetooth headset plus one obsolete telephone handset equals one retro-fabulous hack that I still use today. The best part: Look for this one in Make: volume 20!
I’m a big fan of the hotplate (aka reflow skillet) method of surface mount soldering. Over the course of a few months I designed, machined, and assembled this PID-controlled soldering hotplate to help build the first few prototypes of my AVR HV Rescue Shield kit. Hacking around in the garage is always fun, but creating a new tool is one of the most rewarding things I have can think of.
Here’s a video of the hotplate in action, reflowing the step-up converter on the Rescue Shield:
What started as a simple hack to save a crippled AVR microcontroller eventually became a kit that I’ve sold to AVR enthusiasts around the world. The AVR HV Rescue Shield includes a cool custom PCB, integrated 5V-12V step-up power supply, and is completely open source. I only made one batch of these, and when they’re gone, they’re gone, so head over to the AVR HV Rescue Shield product page to order one today!
Certainly the most famous project on the site, my Wifi Radio project has inspired many readers to start playing with cheap wireless routers and embedded Linux. If you haven’t seen it before, the finished project sounds something like this:
I brought the Wifi Radio to the Maker Faire in San Mateo in May. Everyone loved it, including some of the Make: staff, which got me a blue ribbon for the project. Awesome!
Well, that’s it for year one… If I missed one of your favorite posts from the past year, leave a comment! If you’re new to the blog, happy reading, you have some catching up to do. 🙂
Here’s to another fantastic year of hacks, projects, kits, tools, and resources at mightyohm.com!
How to Repartition Your Hard Drive (manually)
I recently decided I needed to upgrade my garage electronics bench to include capability to work on surface mount components. I ordered a hot air reflow station and some no-clean solder paste from SRA.
Solder paste is a little tricky to handle, because most solder paste needs to be refrigerated at 32-50°F to maintain it’s shelf life. Stored at room temp, it tends to get tacky and dry out within a few weeks. Solder paste is also toxic (it contains lead among other things) so it’s not something you want to put in the fridge with your meatloaf.
I had an old beer cooler sitting in the garage that Kylie picked up on the street a while back. It uses a Peltier thermoelectric cooler to cool the inside and can achieve sub-freezing temperatures.
Since I didn’t want to leave the cooler on constantly, and below freezing is actually too cold for solder paste, I decided to add a PID controller to the cooler to create a solder paste fridge for the garage. To do this, I needed the following items:
Since the PID controller happens to run on 12V I was able to use the existing 12V power supply for the cooler to power everything. I configured it so that if the desired temperature is below the current temperature, the PID controller turns on the MOSFET which supplies power to the Peltier cooler and it’s associated fans.
The only hangup I had was that at first I didn’t place the 1k resistor across the output of the controller, and the cooler would stay on constantly. It turns out that because MOSFETs have almost no gate current, once the PID controller turned off it’s 15V output, the gate of the FET would continue to float high. The bleed resistor to ground ensures that this can’t happen, and the FET turns off properly.
Here’s a picture of the finished solder paste fridge complete with PID controller (click for a larger version).
You can check out a bunch more photos of the cooler on flickr. It should be possible to perform this modification on a more conventional mini-refrigerator as well for better control over the temperature, provided it uses a Peltier cooler, or maybe you could even build the whole thing from scratch using a Peltier cooler off ebay.
