Monday, January 20, 2014

Harvey the RV

For a little while now (since about June of 2013) we have had an RV that is completely solar powered. An onboard inverter allows use of 120V appliances like A/C, microwave, coffee pot. The design has to be just right to get high current loads like them to work on a 12VDC based system. I have some pictures I will post later detailing this. The fun part is that there is a Raspberry PI server on board (also named Harvey) that logs the voltage, current, and battery state, as well as various temperatures on board. I hope to add more monitoring capability and sensors later. It is neat to see that it is basically self-sufficient, using only a wi-fi connection from the TardHaus. It is cold and snowy but server Harvey is still monitoring. Check it out at:

Thursday, December 20, 2012

Information Via Flowchart

I have been a Tard at Large for some time now.  When my washing machine broke recently, I informed my roommates via flowchart.

When I pulled the washing machine away from the wall to open it up, the first thing I thought of my time at Tardhaus.  Before I lived at Tardhaus I would not have had any idea how water pumps, electric motors, knobs and controls, or any of the other stuff in the Washing Machine worked.  But now, I have no fear to rip something open and check it out.  I found the broken mount for the motor and it is now operating just fine.

Monday, October 15, 2012

Getting AWS (Ada Web Server) running on a Raspberry Pi

I was happy to see that multitasking is supported in Ada on the raspberry pi.  This means that Ada Web Server should run just fine, so I hunted up the commands to get it installed.  It's generally much easier to install the packages from the linux distro repository, and that's what I did using the commands below:

Starting with a fresh copy of raspbian, I installed the gnat Ada compiler and aws with the following commands:

sudo apt-get install gnat
sudo apt-get install libaws-bin libaws2.10.2-dev

I'm an emacs fan, so I also installed my favorite editor:

sudo apt-get install emacs

A quick hello world web server was written and everything seems to work!

Monday, July 30, 2012

Surface Plate

 I've been interested in getting into hand scraping, for some of the small mechanical things I make.  I don't have access to a surface grinder, but scraping will let you get things flat down to 0.0001 inch if you have patience and persistence.  This makes it so parts mate nicely and move smoothly.  To make really flat parts you need a reference flat surface, often called a surface plate.

I'd been hunting around the interwebs for a granite surface plate.  There are cheap ones from China that would probably do the job, but I really prefer USA made tools when possible.  I happened to find that Rock of Ages, a granite quarry about half an hour from my house, made surface plates.  I gave them a call and ordered a 12"x12"x4" surface plate with 0.0001 accuracy.  That means no point (on the top side of the plate only) is higher or lower than any other point by more than 1 ten-thousandth of an inch!
I don't really need this level of accuracy, but it didn't cost that much more than the next level down.  I'm super excited that the granite is local and so is the work that was done to make it flat.

Sunday, July 1, 2012

This is my first 3-D printed object used in a sandmold to cast a copy in aluminum.  This is a dragon medallion from  The edges came out a bit rough as there was no draft angle, but the dragon imprint came out well.  The sprue and riser are still attached to the aluminum medallion in this photo.

Wednesday, February 15, 2012

More 3D printer to the rescue

The knob to my GPS holder fell off and was lost.  I found a good looking replacement knob on Thingiverse (a web site where you can download 3D designs for printing) and made a few changes.  I added a hub and a hex shaped hole to capture a nut.
The knob fits quite well and works great.  I printed it out of black ABS and you wouldn't even know it's not original unless you looked real close.

Wednesday, January 4, 2012

Fixing Things with a 3D Printer

The drill press at work has a plastic holder on the side to hold the key for the chuck.  It broke.  I took a few measurements with some calipers and created a 3D model in OpenSCAD.  I made my version a little more rugged than the original.  Then I printed it on my Makerbot Thing-O-Matic 3D Printer.  After a little bit of sanding to remove any sharp edges, I installed it on the drill press.