Skip navigation
1 2 3 4 Previous

Frank Milburn's Blog

48 posts
While building the Rainbow Ukulele this last week I was reminded of another project from quite some time back.  About 20 years ago I was in a large music store in Houston and saw a used Fender Jazz 5 string guitar neck in good condition without the hardware near the counter where the guitar technician worked with a price tag of $5.  My son plays the acoustic double bass and I thought building an electric instrument with him might be fun so I bought it.  Five strings are less commo ...
In a recent post by shabaz a clever method for lifting tactile switches up to the correct height to fit an enclosure is described.  There is also a useful list of switches with caps that fit.  That post inspired me to revisit a method I have used in the past and upgrade it.   My somewhat cruder method involved cutting off the tops of extra long tactile switches.  The body of the switch is tapered which meant no single cap would fit and so I used them without caps. The imp ...
UPDATE 31 August 2019:  See my RoadTest of the Raspberry Pi 4B using OpenCV to do face recognition here UPDATE 23 August 2019:  This is an update of an earlier post about a RoadTest of the Raspberry Pi 4B with a comparison to the Raspberry Pi 3B+ using OpenCV to do facial recognition.  Issues were identified in that post that held up the RoadTest.  The issues have now been resolved and the solution posted at the bottom of this post.   I am one of the fortunate persons ...
Introduction   This is the follow-up to a post about a simple programmable DC electronic load.  Progress has not been as good as hoped and the project needs to be set aside for the time being so other priorities (like a RoadTest and life in general) can be pursued.  Hopefully this documentation will allow it to be picked  up at a later time and completed.   In the first post a design was built and tested on a breadboard, followed by perfboard.  Opportunities for i ...
Introduction   In this blog, the features of three popular oscilloscopes marketed as being entry level will be reviewed and compared.   Keysight DSOX1102G hereafter referred to as Keysight Rigol DS1054Z hereafter referred to as Rigol Siglent SDS 1102CML hereafter referred to as Siglent     tl;dr – See Conclusions at the bottom of this post.   The comparison will highlight features and ease of use and will not be a tutorial on how to use the scopes.  Th ...
I was fortunate recently to win the Experimenting with Polymer Capacitors competition here on element14 and have also been successful in several RoadTests and Project14 contests.  Other successful element14 members have published their entries and I have benefitted from reading them.  For example, find links on entries from the following persons below:   Jan Cumps Donald Lane Douglas Wong   Although I have an engineering degree and lots of experience it is not primarily i ...
fmilburn

Robot Camp

Posted by fmilburn Top Member Jun 30, 2019
This blog has no other purpose than to encourage passing on some of our knowledge to the next generation.    Every summer my grandson and I get together for a week to "do electronics" as he calls it.  Robots are always involved.  This year his younger sister was old enough to join.   Day 1:  They arrived late in the evening.  I had a scrolling sign up at the front door welcoming them which used the Arduino MKR1000 and MKR RGB shield that I received from elem ...
9 August 19 Update:  8 July 19 Update:  A protoboard was populated for further testing and described at the bottom of the post   I have wanted to build a programmable DC load for some time and have followed both this one by Jan Cumps et. al. and also this one by John Wiltrout.  After lots of thought and no action I decided yesterday to just build something with what was on hand.    Specifications   Max 15V input and 2.5 Amps Min 1.8V and 0 Amps Resoluti ...
I have used right angle LED indicators on a number of projects in the past and have a small collection of them. The problem with such things, even were I to have a larger collection, is I never seem to have the right one when I need it.  In the past I have had to make do with the wrong color, wait on an order, or even just bend LEDs over without a fixture. But now I have a 3D printer that needs warming up so I decided to see if I could print a fixture.  The specifications I set for ...
This is a refresh of an old project I did and posted elsewhere quite sometime back.  I am publishing it again so that I can point to it for an upcoming project if needed. That project requires a square wave and thought I would see how well this works before borrowing a friend's function generator.  Since I only need a relatively low frequency square wave, it might also be possible to just use the microcontroller itself.  In any case, here is my AD9850 Frequency Generator BoosterPa ...
EDIT 24 Oct 2018  The schematic in this post contains an error.  It will be reposted after receipt of the PCB and testing.   I am developing an inexpensive but reasonably accurate meter for measuring resistance in the milliohm range.  The previous posts are listed in the related links at the bottom.  In this post the design for the working prototype is expanded to include a second current source for measuring resistance up to 400 ohm and provision made for future auto-r ...
I am developing an inexpensive but reasonably accurate meter for measuring resistance in the milliohm range.  The three previous posts are listed in the related links at the bottom of this post.  In this post a working prototype is presented that has milliohm accuracy down to one millivolt.  A schematic and test data are presented along with plans for the next steps.   Current Status That heading above is supposed to be a pun :-).  Much of the work since the last post ...
Introduction This is the third post on the development of an inexpensive but reasonably accurate meter for measuring resistance in the milliohm range. In the first post a simple current source was described that created a 10 mA current  across a resistor that allowed the voltage drop to be measured using a multimeter and the resistance calculated.  A number of helpful suggestions were received and I ordered additional components based on that feedback.  In the second post a block ...
Introduction In my last post I described a simple circuit that produced a reasonably accurate 10 mA current source to allow measurement of DC resistance down into the milliohm range.  I received  a number of helpful suggestions on how to improve the circuit as well as great discussion on selecting precision parts.  This post will outline several approaches I have considered on how to proceed.  As a refresher, here are the design objectives originally posted: Inexpensive Can ...
Introduction I was inspired by a recent post from shabaz on Building Kelvin (4-Wire) Test Leads.  Shabaz explains in detail and with clarity why measurement of small resistances with the two leads on a multimeter is difficult.  This got me to thinking about how I might build my own 4-wire Kelvin instrument.  This post will describe initial tests of a simple current source that can be used with a digital multimeter to more accurately measure small resistances.   Method and ...