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Frank Milburn's Blog

44 posts
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 ...
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 Resolution 1 mA Deliver 10 mA +/- 1 ...
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 ...
In this blog I intend to outline a reasonably simple way to control Wi-Fi enabled Arduino compatible boards and single board computers like the Raspberry Pi or Beaglebone.  In addition an Apple or Android device that can run the Google Assistant app is needed.   Introduction   I have been thinking about this for a while and there are a number of approaches.  For example, two Ben Heck episodes Part 1 and Part 2  automated the workbench with voice control using Alexa. ...
UPDATED August 24, 2018 at the bottom of the post with parametric data at different voltages and gains   I have a project in mind that will require op amps and have been testing the Texas Instruments MSP430FR23xx microcontrollers with built in op amps. Yesterday I did initial tests with the MSP430FR2355 LaunchPad and looked at how gain can be set from inside the microcontroller.  The input voltage of 32.7 mV was very close to the lower rail  (the rails are GND and 3V3) with gain ...
As noted yesterday I have a project in mind that would use operational amplifiers.  Several manufacturers have microcontrollers with built in op amps and yesterday I took a quick look at the MSP430FR2311 from Texas Instruments.  Today will be a quick look at the larger and more powerful MSP430FR2355 which can be obtained on a LaunchPad.  This is a relatively new product and I bought my sample from the Texas Instruments store as it is not yet available from Newark / Element14.  ...
I have a project in mind that requires operational amplifiers.  Recently Texas Instruments has released several microcontrollers that have low power precision op amps built in.  I have two in hand now that I will be testing - the MSP430FR2311 that is in this post and the larger MSP430FR2355 that I may end up using in my project.  I won't describe the parts in detail today but instead will fire the FR2311 up in a kind of hello world for op amps.   The FR2311 microcontroller h ...