True bypass with DPDT and LED indicator

March 31, 2020

Typically to get true bypass with an indicator LED, you need a 3PDT.  Sometimes these are hard to source, and even when found, quality can be less than perfect.  To get around this you can use relays to control switching of your circuit, or you can use Joe Davidson’s LED trick.  I’ve used this successfully and really love the simplicity and the fact that I can use parts I typically have on hand already as well.

Joe Davidson's LED trick

Joe Davidson’s LED trick allows for using a SPDT switch, LED indicator, and still maintaining true bypass.

Posted in Circuits and Electronics, Music | Comments Off on True bypass with DPDT and LED indicator

Simple guitar cable tester

March 31, 2020

With social distancing being the current norm, I’m working primarily from home right now.  As such, I found I needed to clean my work area.  Doing this, I also found I had a lot of random bits around and decided to make something of them.  Here is a simple cable tester I’ve made based on ideas found at diystompboxes.com.  I shared the idea and more photos on SSGuitar.com, but here is the short version:

Simple guitar cable tester

Note: I chose to omit the speaker and subbed R1 with a 1k to reduce brightness.

 

Good cable!

No lights on means the cable is electrically open.  Just the red LED on means there is a short.  Both lights means you are in business!

 

 
Posted in Circuits and Electronics, Hobbies, Music | Comments Off on Simple guitar cable tester

Raspberry Pi Digital Signage

December 18, 2019

There have been many different attempts at inexpensive digital signage over the years.  My favorite, one that I use regularly where I work, is Raspberry Pi for digital signage.  Put simply, I set up a Raspberry Pi to load a continuous loop of a Google Slideshow.  This refreshes once every 15 minutes to load new content.

Here’s how we do it.

First, run all updates on your new Pi. (sudo apt-get update, sudo apt-get upgrade).  I like to also run sudo apt-get dist-upgrade and sudo autoremove to fully upgrade plus clean things up.

Next, install clutter and automation (sudo apt-get install clutter and sudo apt-get install automation).

Set your auto config to keep the Pi from going to screensaver as well as load the slideshow automatically on boot.  The file you need to edit is /etc/xdg/lxsession/LXDE-pi/autostart.  You’ll want it to look like this:

@lxpanel –profile LXDE-pi
@pcmanfm –desktop –profile LXDE-pi
point-rpi
@xset s off
@xset -dpms
@xset s noblank
chromium-browser –noerrdialogs –disable-infobars –incognito –kiosk http://web.address.com

Now edit crontab to refresh every 15 minutes (crontab -e):

#Refresh every 15 minutes
*/15 * * * * xte “key F5” -x:0

That’s it!  Enjoy your new digital signage!

Posted in Computers and Hardware, Technology | Comments Off on Raspberry Pi Digital Signage

Truer words

December 17, 2019

“We are made to persist, to complete the whole tour.  That’s how we find out who we are.”
– Tobias Wolff

Posted in Personal, Ponderings | Comments Off on Truer words

555 Metronome

April 22, 2019
My 555 metronome, all boxed up.

I wanted to make a metronome and decided on the venerable “555” chip. In this case I used an LM555CN. I had all components needed except the IC itself, so I ordered a handful (they are only about $0.75/each) and started the process. This was my first time playing with a 555, and it was great fun!

I started with this circuit from Jameco. Then I breadboarded and made changes until I was happy. The original circuit gave roughly 25-550 BPM which was pretty wild – standard metronomes are 40-208 BPM. My circuit as adjusted gives me 35-200 BPM which is close enough for my purposes.

I used Krita to edit the original schematic after making my changes to “dial in” this metronome circuit.
This is my layout for my modified 555 metronome circuit. I created this layout using DIYLC from Bancika.
Posted in Circuits and Electronics, Music, Projects | Comments Off on 555 Metronome