Author: Bryan Bibeau
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Building a temperature well
Finally finishing up a project I started a few months back. This is a peltier junction temperature well for calibrating meteorological sensors.
The Peltier junction is controlled via an Omega PID controller, and utilizes an h-bridge for switching polarity to the cooler. An RTD sensor provides temperature feedback to the PID. This allows the well to be heated or cooled for different testing levels. I turned the well out of Aluminum, with a 1.50″ ID, so that it will receive off-the-shelf aluminum inserts for different sensors. The inserts can be drilled out to match whatever unit you have under test. I’m also going to make one insert that allows for propylene glycol baths.
This first unit was a bit of a science experiment. I will be building 2 more of these as “final” products for work, and for those I’ll lay out a circuit board to handle all the electrical connections, so that each component can be plug-able.
This unit is capable of -10C to +50C under normal conditions. Right now it has a 3-stage Peltier thermoelectric junction. I’m going to add another 3-stage unit. -50C is my goal for adjusting the offset on temperature sensors. If anybody is interested in one of these, I can make you one! -
Lathe project
Did a small job on Saturday repairing a farm implement for a coworker. I had to cut off the damaged threads, bore it out and tap it, then install an exhaust stud with loctite.
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Track our hike in Capitol Reef National Park
Testing out my new TH-D72A in APRS mode. It looks like there should be a repeater on Mt. Ellen that will pick us up. This should start showing data points on Friday, March 9th.
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UV3D APRS working!
My problem turned out to be power related. Whenever the TT3 would transmit, the voltage would drop to around 4.7v and it would reset. I added a LM7805 with 4 AA batteries, and it is working reliably now. I also moved it from the breadboard to a circuit board so I can test it on the highway.
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Wouxun UV3D APRS
Finally was able to get my homemade APRS transmitter working tonight! I’m using a Byonics TinyTrak 3 SMT TNC with a Parallax GPS, hooked to my Wouxun HT. There seems to be something weird going on with the PTT circuit that I haven’t quite figured out yet. The TT3 doesn’t always seem able to pull down the 5V PTT singnal on the handheld. I’m thinking about adding an external transistor if I can’t get it to work reliably.
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Trip planning for Capitol Reef Backpacking Trip
Erin and I are starting to plan for our Spring backpacking trip to Capitol Reef National Park in March. We’re going along with some folks from my work, and our friend Megan from Park City, UT. We’ll spend 3 days in the lower Waterpocket Fold area. It’s a 9.5 hour drive, but should be totally worth it, especially if we luck out with some nice Utah sun!
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School Bus Trip Photo Slideshow finally finished!
Here is a slideshow I made from the pictures taken on our fall ’11 School Bus adventure vacation from Maine to Idaho and back.