Some really cool photos are coming in, check them out below or click the link to go over to flickr and view the entire group pool.
Printed circuit boards can be interesting and beautiful, with their delicate traces and colorful components in all shapes and sizes. I just created a new Flickr group for photos of printed circuits like the one shown above. More details about the group can be found on Flickr:
Photos exploring the beauty of printed circuit boards and components, including both surface mount and through-hole PCB construction.
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.
“Wiring harnesses are an essential and often overlooked part of any electrical system. On a car, a good wiring harness can make the difference between a weekend joyride and a long tow home. Building a quality wiring harness requires a couple inexpensive tools and the right techniques…”
The Maker Faire is an event held twice a year (alternating between San Mateo, California and Austin, Texas) by the folks at Make Magazine, one of my favorite publications from O’Reilly. The event centers on DIY culture, covering everything from making combat robots to felting and needlepoint.
This year I participated in the 2008 Bay Area Maker Faire in San Mateo and showed people how to make better wiring harnesses for things like cars and electronic projects.
During the Maker Faire I handed out a one page tutorial with information about where to buy the tools and supplies as well as the steps needed to create a template and make a wiring harness from scratch.
Or grab it in .png format, click on the image below for a full size version.
Check it out and let me know what you think.
This past weekend, I attended The Last HOPE at the Hotel Pennsylvania in NYC. The con was awesome and I had a great time. This was my first HOPE, and I noticed a few strong themes this year, including:
It was announced during the closing ceremonies that the Hotel Pennsylvania will not be demolished as was previously announced, and that there will indeed be another HOPE in 2010.
NYC Resistor has some info about the 3D Wiremap demo, one of my favorite exhibits, shown below.