Pages Menu
TwitterRssFacebook
Categories Menu

Recent videos

More
  • Engineering a better drummer?
  • Nano-meter precision positioning
  • Universal Robots

Most recent articles

New Build: Upright steamer trunk bass

Over the last several weeks I made this upright bass out of an old steamer trunk I found at a thrift shop for $10 (no Macklemore jokes please).

Here is the finished product, but keep reading for more finished pictures and a description of my process.

The finished trunk bass.

The finished trunk bass.

Several years ago I tried building an upright bass for the first time, using a metal washtub that can be bought at any hardware store for a few dollars.  It was quite the learning experience, I ended up having quite a few things that just didn’t satisfy me about it.  Here are a couple of pictures from that build:

Obviously I made a lot of mistakes since it was my first attempt at something like this.  I was never quite satisfied with how it turned out, but it did see a lot of stage use!  Here are a couple of action shots:

 

Action shot of the washtub at the Flagstaff bluegrass festival

Action shot of the washtub at the Flagstaff bluegrass festival

Washtub bass on stage

Ryan got a lot of good use out of it!

 

Here is the trunk before I did anything to it.  The handles were already gone when I got it.

Here is the trunk before I did anything to it. The handles were already gone when I got it.

I finally decided it was time to make a new and improved version when I found this old steamer trunk at a thrift shop for $10, and I really liked the look of it for a bass.  You can see it here before anything was done to it, although I have some wood set out to make the first few cuts.  You can also see the old bass in the background, I had it there to take measurements as I worked (mainly to fix all the mistakes I made the first time).  I didn’t work off any plans, just used my previous work and some quick calculations to figure it all out.  One of my favorite things about this project, I already had most of the stuff needed to make this bass.  The tuners and pickup were the most expensive part of the last build, and this time I could just use the ones I had from before.  That made this bass much cheaper than the last, although better in the end.

 

It might be easier to show the rest of the process in captions:

 

Hole cut in the trunk to mount the main structural support.  It has a wedge glued to it to give the neck the proper angle in relation to the trunk.

Hole cut in the trunk to mount the main structural support. It has a wedge glued to it to give the neck the proper angle in relation to the trunk.

Grooves cut into the back neck layer to add carbon fiber stiffening supports.  This will solve some of the flex issues I saw with my previous build, as well as giving it an increased sustain and larger tone.

Grooves cut into the back neck layer to add carbon fiber stiffening supports. This will solve some of the flex issues I saw with my previous build, as well as giving it an increased sustain and larger tone.

 

A few images of test fitting everything together, prior to glueing.

A few images of test fitting everything together, prior to glueing.

Angle view of test fitting, you can see the neck angle from the wedge.  It's almost looking like an instrument.

Angle view of test fitting, you can see the neck angle from the wedge. It’s almost looking like an instrument.

Front angle of test fit

Front angle of test fit

Laying out the headstock was the biggest challenge.  On my previous attempt the headstock had to be rigged numerous times to get it to tune up properly.  I wanted this one to work the first time.   You can see the tuners held in by tape to check the fit.

Laying out the headstock was the biggest challenge. On my previous attempt the headstock had to be rigged numerous times to get it to tune up properly. I wanted this one to work the first time. You can see the tuners held in by tape to check the fit.

Another view, you can see the carbon fiber stringers in this view as well.

Another view, you can see the carbon fiber stringers in this view as well.

Time to glue it all up.  String was strung tight to allow me to clamp the neck straight to the body.  This glue joint took somewhere around 2 hours of prep, but only 1 minute of actual gluing before it was done.

Time to glue it all up. String was strung tight to allow me to clamp the neck straight to the body. This glue joint took somewhere around 2 hours of prep, but only 1 minute of actual gluing before it was done.

Clamp it down tight.  This  joint has to hold against over 400 lbs of string tension, which translates to a much higher stress at the joint.

Clamp it down tight. This joint has to hold against over 400 lbs of string tension, which translates to a much higher stress at the joint.

After the glue has set for a bit, it's time to get back to work.  Clamps get left on though.  You can see the headstock is getting closer to completion.

After the glue has set for a bit, it’s time to get back to work. Clamps get left on though. You can see the headstock is getting closer to completion.

Closeup of the headstock, with the contour cuts for hand comfort and appearance.  I added a small block to cover the stringer grooves.

Closeup of the headstock, with the contour cuts for hand comfort and appearance. I added a small block to cover the stringer grooves.

Another view of the headstock.

Another view of the headstock.

Here is a side view of the bass, nearing completion!

Here is a side view of the bass, nearing completion!

After giving it a few hours for the glue to set, it's time to start sanding.

After giving it a few hours for the glue to set, it’s time to start sanding.

Keep sanding!

Keep sanding!

Front view after sanding.  The goal was to get every corner rounded off, and no splinters to catch my hand!

Front view after sanding. The goal was to get every corner rounded off, and no splinters to catch my hand!

After 24 hours, it's safe to apply tension to the glue joints.  I put the exact same strings on as the previous bass.  The washtub is officially in retirement.

After 24 hours, it’s safe to apply tension to the glue joints. I put the exact same strings on as the previous bass. The washtub is officially in retirement.

 

So that’s the build.  Here are some more pictures of the finished beast.  Thanks for making it this far, hope you enjoyed it!

 

Extend your battery life by keeping your computer OFF

Greener computing, computers that use significantly less power, might be coming soon.  How?

They turn themselves off between every keystroke, mouseclick, or touch.

The Journal of Applied Physics has published a very interesting article this week.  The technology, Magneto-resistive Random Access Memory (MRAM), is over a decade old now.  It uses two plates which can each be assigned a magnetic field direction.  The data is read back by measuring the resistance across the plates, if the reading is low resistance then the fields are aligned.  High resistance means they are opposing.

The size of the cells in in MRAM (each cell can store a bit) and the high current necessary to program them are the limiting factors in this technology, but enter the Spin Transfer Torque methodology.  This concept uses the spin direction of electrons to modify the magnetic properties, drastically shrinking the cell size, which increases the memory density.  This technology still has some development, but it has the advantage of significantly lower power demands.

Conventional DRAM requires a relatively high percentage of a computer’s power demands, it uses a small capacitor to store an electric charge with a transistor to control it.  This means it is constantly drawing current from the main computer power source.  MRAM-STT needs power when modifying a bit, but otherwise can be shut down.  For any given bit in memory, it is likely that it spends more time being unchanged than changed, meaning the majority of time it can be shut down.  The concept of the article is that it would be possible to build a computer that shuts itself down whenever there is a break in usage of a few milliseconds, then turn itself instantly back on.  The power savings would be immense, and could allow computers to be run off alternative energy sources (solar, hand-crank, thermal).

There are quite a few details yet to be worked out.  If you were  to read through the journal article, you would see that there are still limitations in size and speed, but the analysis shows that we are still moving toward the end goal of a more energy efficient computer.  Personally, I’m looking forward to cell phones that can last through the day while actually using them continuously.

 

K. Ando, S. Fujita, J. Ito, S. Yuasa, Y. Suzuki, Y. Nakatani, T. Miyazaki, and H. Yoda. Spin-transfer torque magnetoresistive random-access memory technologies for normally off computingJournal of Applied Physics, 2014 DOI:10.1063/1.4869828