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Replacing LabVIEW with Python, Part 2

Jason Jones — Wed, 27 May 2020 23:30:00 -0400

Software Stacks

Anyone already familiar with Python - particularly from the data science perspective - will already be familiar with the majority of the contents of this brief article. In short, this article will introduce some of the software that will be utilized during your test development.

numpy
pandas
matplotlib
pyvisa / pyvisa-py …

Replacing LabVIEW with Python, Part 1

Jason Jones — Sun, 08 Mar 2020 23:30:00 -0400

Strategies for Choosing Hardware

Much of this document is strategized to reduce your time developing harware APIs.

Ask a Friend

My strategy for choosing hardware: ask a friend! If your friend can save you a few hundred dollars and a couple of days of effort, go for it! Ask for …

Replacing LabVIEW with Python, Part 0

Jason Jones — Sun, 01 Mar 2020 23:30:00 -0500

Introduction

The use case described herein involves prototype and manufacturing test applications almost exclusively. I do not intend to suggest that Python can or should replace LabVIEW in all applications, but I have found that, in this particular use case, Python is particularly well suited.

I am an electrical engineer …

Building a Pelican Blog with Bitbucket Pipelines

Jason Jones — Thu, 24 May 2018 22:55:00 -0400

I haven't exactly made it a secret that I use Pelican to write this blog. Sometimes I'm active, and sometimes I'm not. As pelican is a static site generator based on templates and text files, I have been doing the build and deployment by hand. When I have been away …

Reynolds Number with Python and Pint

Jason Jones — Thu, 16 Nov 2017 00:00:00 -0500

I had an instance at work where I needed to quickly calculate an estimate for Reynolds Number for 0 gallons/min to 10 gallons/min for several different pipe diameters.

$$Re = \frac{QD}{vA}$$

$Re$ = Reynolds Number (dimensionless)
$Q$ = volumetric flow rate ($m^3/s$)
$v$ = kinematic viscocity of the …

KiCAD Copy and Paste

Jason Jones — Mon, 06 Nov 2017 17:41:00 -0500

Introduction

Throughout the last few years, KiCAD has been my goto tool as a hobbyist and as a professional. I readily admit that KiCAD lacks some of the polish and features found within Altium, Allegro, and PADS. Despite the lack of features, KiCAD has one advantage that those packages did …

Dispatch How-To

Jason Jones — Wed, 04 Oct 2017 18:28:00 -0400

Purpose

This document is intended to provide a guide regarding the use of Dispatch.

Source code may be found on github.

Concepts

Structure

The Dispatch library consists of two primary components, the dispatch source and header and the framing source and header. Dispatch acts as the intermediary between your application …

Load Time from a Browser to a Raspberry Pi

Jason Jones — Fri, 18 Aug 2017 22:16:00 -0400

Introduction

I recently had a work move and wanted to make something of an impression. My ambition to be, both, productive and cool has led me to the relatively simple project of placing a coffee cam in the workplace.

Ideally, I could attach a pi with a camera to the …

Curve Tracer Reference

Jason Jones — Tue, 13 Jun 2017 20:10:00 -0400

Purpose

This document is intended to document the curve tracer This document will be updated through revisions and can be used as a persistent reference, regardless of the 'date posted'. As more information becomes available, documentation will be added.

The original post for the curve tracer can be found here …

Engineering Notation in Python

Jason Jones — Fri, 02 Jun 2017 21:01:00 -0400

Engineering Notation

Anyone reading this will likely already have a background that covers engineering notation, so I won't go into it deeply. Computer scientists might also call engineering notation a 'human-readable' numbers. Instead of 4096B you might see 4kB or 4.096kB, depending on your precision.

There are more expansive …

Review: Python Jumpstart by Building 10 Apps

Jason Jones — Thu, 11 Aug 2016 23:30:00 -0400

What is It

Python Jumpstart by Building 10 Apps is a course designed as an introduction to Python. This course is not your typical introduction found on Coursera or EDX, which are usually designed around some weeks-long introduction that get you to objects around week 8. This course - which you …

Load Cell Sensor Introduction

Jason Jones — Tue, 02 Aug 2016 07:35:00 -0400

Load Cell Amplifier

I was browsing Sparkfun a few days ago and came across their OpenScale board. The board is basically a load-cell amplifier with a microcontroller interface which will output data - via an FTDI chip - to the PC or other UART at a fixed interval. The microcontroller also has …

Fan Controller Progress Update - July

Jason Jones — Thu, 21 Jul 2016 11:05:00 -0400

Hardware

Hardware was received and built up quickly in the past couple of days. In fact, all has progressed more quickly that I initially imagined. Osh Park - those loveable guys - bumped my order up to the 'premium' panel, so I received the boards a week earlier than anticipated!

Rework

That …

Project Curve Tracer: XY Outputs

Jason Jones — Thu, 14 Jul 2016 08:51:00 -0400

Oscilloscope XY Outputs are Working!

Using two PWM outputs and using a couple of simple RC circuits on the board, we have managed to get the XY outputs working well enough to display on any oscilloscope! I now feel that the hardware is feature-complete!

Status

The hardware in github is …

Fan Controller Introduction

Jason Jones — Mon, 11 Jul 2016 11:20:00 -0400

Sorry that it has been so long since our last post. I have been out on vacation for a bit with some family and am just getting back into the swing.

PC Fan Controller

I recently wished to add a fan to my PC and I realized that I only …

SolidWorks to Inkscape for Laser Cutting

Jason Jones — Thu, 23 Jun 2016 11:15:00 -0400

Intro

In this article, I am going to guide you through an easy way to transfer your SolidWorks design into Inkscape in preparation for laser cutting. There is already some information out there, but the guides appear incomplete, so I'm tossing in my $0.02.

This will not be a …

Project Curve Tracer - v1.1 Model

Jason Jones — Mon, 20 Jun 2016 12:00:00 -0400

Modeling Software

I am a big fan of SolidWorks as a 3D design package. I am completely untrained, yet with a few hours of practice, anyone can pick up the software and do something useful. After a while, you can start to do some really nice things with it!

The …

Project Curve Tracer - June Progress

Jason Jones — Tue, 14 Jun 2016 16:10:00 -0400

Repository Adjustments

As the hardware is at the point of initial release, but the firmware and GUI aren't quite there yet, I decided that it would be prudent to split off the firmware and GUI components into their own GIT repositories. Tracking all files in the same repository was convenient …

Project Curve Tracer: Design Refinement

Jason Jones — Tue, 07 Jun 2016 20:30:00 -0400

Design Refinement

There have been a couple more patch wires and a bit of scope creep, but no show-stoppers and a fair amount of added functionality.

Since the last post, we have:

Added an offset calibration mode which removes any voltage offset that may exist
Added a three-terminal mode which …

Project Curve Tracer: Bringing Up the New Boards

Jason Jones — Tue, 31 May 2016 08:21:00 -0400

Current Board Status

The board is currently working and working well, but there were a few bumps along the way. There always are, but - in this case - they were slightly more than expected.

Surprises

After the last revision, we thought that the kinks were worked out of the schematic. There …

Project Curve Tracer: Visualization Maturing

Jason Jones — Thu, 26 May 2016 09:20:00 -0400

Making Progress on the GUI

As you can see, the visualization tool is becoming more mature. We have taken the visualization scaffolding developed in the last post and added a few elements to each frame. It is amazing what a few buttons and menus will do for the looks of …

Dispatch Visualizer

Jason Jones — Tue, 24 May 2016 13:19:00 -0400

Vision

For some time, I have been working in small portions on Dispatch as a serial library for the curve tracer. Initially, I thought that the serial library would be limited in scope to that particular project, but I began to see that the library could, potentially, be very useful …

SerialDispatch is now on PyPI

Jason Jones — Mon, 23 May 2016 13:43:00 -0400

The title pretty much says it all! I have put my first package on PyPI! This is something that I have been curious about for quite some time, but never had the need to do until this project.

I had to rename the python port to "serialdispatch" since "pydispatch" was …

Project Curve Tracer: Visualization Scaffolding

Jason Jones — Fri, 20 May 2016 16:54:00 -0400

Window Layout

Scaffolding Appearance

As you can see above, the scaffolding of a somewhat more sophisticated is complete and ready to be populated. You may recall that the original visualizer was adequate for the immediate task, but lacked a certain sophistication and control that would be quite nice to have …

Interrupt Concurrency Issues

Jason Jones — Wed, 18 May 2016 20:13:00 -0400

The Symptoms

I have spent my spare time in the past few days debugging a problem that simply wouldn't go away. Every few seconds, there would be a random byte that was simply skipped out of the UART. Fortunately, the checksum was protecting bad data from getting through, but there …

RSS and Atom Feeds!

Jason Jones — Mon, 09 May 2016 14:33:00 -0400

We have Added Feeds!

If you look to the right on the sidebar, you will see that we have added RSS and Atom feeds! This wasn't a critical update, but it was something that I have wanted to do for a bit. In truth, I hadn't used feeds myself, so …

Project Curve Tracer - Another Layout

Jason Jones — Thu, 05 May 2016 15:20:00 -0400

As you can see, we have another layout completed and ordered from the guys at OSH park. This time around, we took some time to place some nice mounting holes and add rounded corners. We will be looking forward to assembling this board!

In the mean time, we will be …

Project Curve Tracer - Next Revision

Jason Jones — Mon, 02 May 2016 10:59:00 -0400

Project Status

As you have seen with a few screenshots, we have made significant progress since the first post. We have completed a schematic, layout, rework, and created a basic code framework. We have proven that the hardware mostly works as-is, but would like to make some improvements. In this …

Project Curve Tracer - Capacitor Shots

Jason Jones — Fri, 29 Apr 2016 08:47:00 -0400

Squashing Bugs

As you recall from the last post, we were able to get a few screen captures of a few components under test, but the pictures were a bit rough. Today, we still have rough pictures, but they are a lot better due to a little effort in reducing …

Project Curve Tracer - First VI Plots!

Jason Jones — Sat, 23 Apr 2016 11:19:00 -0400

The First Shots are In!

After a few weeks of messing around on-and-off with the curve tracer, we finally have some shots to show that the work has not been for nothing!

The Tool

I took the time to write a small TkInter-based plotting tool. I found a couple of …

Introducing Dispatch

Jason Jones — Sun, 17 Apr 2016 19:15:00 -0400

Intro

Dispatch is a library designed to operate on any byte-aligned communication channel. Dispatch has 'endpoints' or 'topics' to which data is written and 'subscriber' or 'consumer' functions to which the data is sent. At this time, Dispatch is primarily written in C, although a Python port does exist in …

Bootstrap 3 Theme

Jason Jones — Sun, 17 Apr 2016 12:14:00 -0400

Ok, so I realize that Bootstrap is going on version 4, but I decided to update from Bootstrap2 to Bootstrap3 anyway.

I wanted to do this for three reasons:

To learn a bit more about the Jinja2 templating engine
To learn a bit more about Pelican and the access to …

Project Curve Tracer - Serial Protocol Part 3

Jason Jones — Mon, 11 Apr 2016 05:54:00 -0400

So, the graphic above looks a lot like something from the 80's. I wanted to put something up since this page was going to be nearly all text, so there ya go.

In Part 1 we described the 'vision' of the protocol that we wish to use, placing a lot …

Project Curve Tracer - Serial Protocol Part 2

Jason Jones — Fri, 08 Apr 2016 08:47:00 -0400

Before we Get Started...

After conferring with the author of the Telemetry library, I am convinced that it will not meet my requirements at this time. I am currently writing this library as part of the curve tracer project, but I feel that it would be best to publish it …

Project Curve Tracer - Serial Protocol Part 1

Jason Jones — Tue, 05 Apr 2016 08:47:00 -0400

Looking for a Serial Protocol

As you know if you have been reading the other articles in this series, the end goal is to display the curve tracer data on a PC screen for the user to consume and to provide controls for the user to interact with the hardware …

Current Sensor Datasheet

Jason Jones — Tue, 29 Mar 2016 00:01:00 -0400

Purpose

The current sensor breakout is a breadboard compatible breakout module for the INA139 series of high-side current sensor ICs. In addition to providing a mount point for the INA139 part and the shunt resistor, the module also includes a low-impedance output suitable for driving an analog-to-digital converter.

Pinout

The …

Project Curve Tracer - Framing Serial Data

Jason Jones — Mon, 28 Mar 2016 07:49:00 -0400

In transferring data, there are many layers that one can add in order to ensure that the communication has certain properties. For instance, up to this point, we have implemented the physical layer and part of the the data layer. The physical layer specifies thevoltages we are permitted to operate …

MicroSD Holder

Jason Jones — Sun, 27 Mar 2016 22:55:00 -0400

It has been a bit a couple of weeks since I last made a post. I am working on the next curve tracer post, but the next post covers a fair amount of material and it takes several decisions to get some of these things going.

I had found myself …

Circular Buffers, Part Two!

Jason Jones — Mon, 21 Mar 2016 19:01:00 -0400

For some background, go back to read the previous post on circular buffers.

Mistakes were made

So, I was implementing a circular buffer on a different project and - lo and behold - I have made a mistake in the implementation of the circular buffer! We last visited the circular buffer in …

Switched Blog Engines

Jason Jones — Fri, 18 Mar 2016 16:05:00 -0400

Aaaannnd we're back!

So I have spent some time converting my posts from wordpress to Pelican and I'm pretty happy with the way things are turning out. There are still some items that need to be gone through. For instance, you can still see the marks from the changeover in …

Current Sensor Board - Testing with a DC Motor

Jason Jones — Fri, 18 Mar 2016 14:00:00 -0400

In previous posts, we tested the DC performance of the current sensor board. In this post, we are going to test the current sensor board using a typical toy DC motor as the load.

DC Motors

A DC motor runs from a DC power supply, but the motor currents are …

Project Curve Tracer: Configuring the UART

Jason Jones — Fri, 11 Mar 2016 16:13:00 -0500

Intro

We have the most basic elements of the curve tracer working, but we have no way to interface with it other than hooking up the Microchip debugger and downloading array variables. In this installment, we are going to make the first steps toward getting data to the PC using …

Project Curve Tracer: Configuring the Oscillator

Jason Jones — Thu, 10 Mar 2016 17:15:00 -0500

If you have no idea what this is about, go back to the Curve Tracer Requirements Post!

Intro

In previous posts, we have been using the maximum speed 32MHz (16MIPS) oscillator. This oscillator is prone to some error and we would like to eliminate that error. In this post, we …

Project Curve Tracer - Implementing the Task Manager

Jason Jones — Fri, 04 Mar 2016 00:44:00 -0500

Intro

From this point on, there are various tasks that need to occur deterministically, but not necessarily via an interrupt. We are going to implement a task manager for this purpose. For readers, this may be familiar. We already implemented the task manager for the MSP430 a few weeks ago …

Current Sensor Board - Testing

Jason Jones — Thu, 03 Mar 2016 14:17:00 -0500

For a project introduction, go back to the first post!

Intro

So, if you are already familiar with the project, you know that I was looking for a quick general-purpose current-to-voltage converter with a low-impedance output. I received boards this weekend and was able to solder together the module today …

Project Curve Tracer - ADC Input

Jason Jones — Wed, 02 Mar 2016 18:56:00 -0500

Intro

Up to this point, we have focused on generating signals without necessarily observing those signals. In this post, we will begin to give the microcontroller the capacity to observe those signals using the Analog-to-Digital Converter (ADC).

ADC Requirements

There are 5 signals to be observed:

LD_VOLTAGE_0 - this is the …

Project Curve Tracer - Setting Up PWM as a DAC

Jason Jones — Mon, 29 Feb 2016 12:00:00 -0500

Intro

In the initial schematic, you will recall that U1 is an opamp in the differential configuration. This means that the voltage at the reference input will be the 'center' or '0' voltage of the output. We decided to place a small RC filter at the input of that opamp …

Project Curve Tracer - Using the On-Die Opamp

Jason Jones — Fri, 26 Feb 2016 00:07:00 -0500

Intro

In the previous post code-oriented post, we got the DAC generating waveforms of reasonable frequencies. Unfortunately, a DAC usually has a high output impedance, which will distort our signals if we place it in the wrong circuit. Fortunately, we can make up for this using the on-board operational amplifiers …

Project Curve Tracer - Schematic Errors

Jason Jones — Thu, 25 Feb 2016 00:00:00 -0500

As always, there are some schematic errors. This is one of the issues with highly integrated ICs, it is so easy to mix up the pins! Maybe I should stop doing schematic and layout so late at night...

Vcap should be on pin 20, nothing else. This error arose from …

Project Curve Tracer - DAC Initialization and Utilization

Jason Jones — Tue, 23 Feb 2016 07:49:00 -0500

Go back to the first post to get some background on this project!

Hardware Patch

Just a couple of notes before we begin coding. I was using the pinout for the "PIC24F" part on the datasheet whereas I should have been using the "PIC24FJ" part. This will involve a small …

A Low-RAM Averaging Technique

Jason Jones — Fri, 19 Feb 2016 22:55:00 -0500

Intro

You have all had to implement a moving average algorithm from time-to-time. Moving averages make life easier, especially for mixed-signal applications in which you have a few extra A/D cycles available.

This article is intended for a fixed-point audience; however, the techniques shown can apply to floating point …

Creating the Current Sensor Board

Jason Jones — Tue, 16 Feb 2016 21:44:00 -0500

Intro

There have been several times that I have had to sense current in an application for one reason or another. I was working on just such an application recently when I thought to myself, "Hey, why don't I just make a quick solderable module and just always use that …

Avoiding Division and Modulo Operations

Jason Jones — Mon, 15 Feb 2016 16:07:00 -0500

You may also be interested in our article regarding fixed-point math!

Intro

Division and modulo operations should be avoided on 8- and 16-bit hardware. We would like to present you with a few techniques that can help you avoid the cycle-heavy division operations by replacing your modulo operators with bit …

Project Curve Tracer - Boards on the Way!

Jason Jones — Fri, 12 Feb 2016 20:57:00 -0500

Boards are on the way from OSH Park, along with parts from Digikey!

We should be able to start coding sometime next week - I always take the free shipping.

I will likely have them soldered up the day they get here since they have so few parts.

As mentioned in …

Testing the Accuracy of libmathq15 on the PIC24

Jason Jones — Thu, 11 Feb 2016 21:04:00 -0500

For a quick primer on libmathq15, check out How Fixed-Point Math Works.

Intro

Recently, I have been curious as to the accuracy of libmathq15 over
the entire sine range, which is 0 to 65535 for trigonometric functions and -32768 to 32767 for the standard Q1.15 functions. Realizing quickly that …

Project Curve Tracer - Layout

Jason Jones — Thu, 11 Feb 2016 12:00:00 -0500

If you haven't read the project documentation up to this point, you may want to go back to the beginning.

If you are ready to dive into the layout, then lets get started!

This will probably be a short post. The layout process was fairly straightforward and resulted in a …

Project Curve Tracer - Schematic Creation

Jason Jones — Wed, 10 Feb 2016 12:00:00 -0500

In the last post, we talked about the component selection. In this post, we will make all connections of the schematic and fill in the details that we skipped.

High-Level Design

I believe that it is often instructive to make a high-level block diagram:

There is obviously going to be …

Project Curve Tracer - Schematic Part Selection

Jason Jones — Tue, 09 Feb 2016 08:47:00 -0500

You may want to go back to Project Curve Tracer - Requirements in order to gain some background on this project.

Shield or Custom?

After thinking about this for a bit, I decided to go against making this a shield for the MSP430 launchpad or Arduino. This decision is primarily based …

Project Curve Tracer - Requirements

Jason Jones — Mon, 08 Feb 2016 12:00:00 -0500

Intro

My first job out of school was as an engineering technician repairing medium to large UPS systems. I only worked there for 6 months, but I learned a lot about the 'real world' and about how to troubleshoot circuits. In my time there, I encountered a piece of equipment …

The Not-Quite RTOS - A Task Manager

Jason Jones — Sun, 07 Feb 2016 12:00:00 -0500

Simplicity is the ultimate sophistication - Leonardo da Vinci

Intro

There was a time sometime long ago when I was looking for an RTOS or something similar which would help me easily schedule multiple tasks to execute deterministically, but not require a lot of overhead. Of course, I came across all …

Circular Buffers!

Jason Jones — Fri, 05 Feb 2016 19:01:00 -0500

A note from the future: This article is a bit out-dated. Please visit the next entry for the updated entries after you have read this article!

Intro

Inspired a bit my the 'Embed with Elliot' article Going 'Round with Circular Buffers, I decided to make a contribution. Read the article …

MSP430 vs. PIC24

Jason Jones — Thu, 04 Feb 2016 16:43:00 -0500

Intro

I believe that I should start out saying that I like both the MSP430 AND the PIC24 series. I was doing some assembly coding on the MSP430 close to the time that I was doing some assembly work on the PIC24 and I noticed that things were taking significantly …

Simple Embedded Unit Testing

Jason Jones — Wed, 03 Feb 2016 23:08:00 -0500

Intro

All of the guys who are software gurus do some sort of unit testing... and you should too. There are lots of tools out there, from the very slimmest to some very expensive packages. I'm going to show you the quick and dirty method that will cover 80% of …

How to Emulate Multiple Interrupt Vectors with a Single Interrupt

Jason Jones — Wed, 03 Feb 2016 17:41:00 -0500

Intro

There are some really great chips out there, many with almost unbelievable numbers of interrupt vectors. Unfortunately, it always seems to come up that you have a single interrupt vector that has to be split between two or more different events.

So you have been an embedded engineering for …

MSP430 - Writing Assembly for use in C

Jason Jones — Tue, 02 Feb 2016 20:21:00 -0500

Intro

This tutorial is geared towards those who want to write hand-optimized assembly code for the MSP430, but don't quite know how to get started. If you are interested in writing assembly on the PIC24 or dsPIC33 series, see our other tutorial on writing assembly for use in C using …

How Fixed-Point Math Works

Jason Jones — Mon, 01 Feb 2016 06:35:00 -0500

What is Fixed-Point Math?

Fixed-point math is math in which the decimal doesn’t move relative to the digits composing the number. Some call this ‘integer math’, which is a reference to the integer form that numbers normally take on the processor in fixed-point notations. Others call this ‘q math …

XC16 - Writing Assembly for Use in C

Jason Jones — Mon, 01 Feb 2016 02:28:00 -0500

Intro

So I have been playing with writing assembly again within the context of C and I have run into the usual issues. I have decided to create a quick little 'getting started' tutorial.

If you are interested in the same type of writeup regarding TI's MSP430 series, head over …

Fixed Point Library Creation

Jason Jones — Sun, 31 Jan 2016 21:11:00 -0500

So I have been doing some reading and looking around recently regarding Q1.15 math and embedded C and I am surprised at the lack of libraries out there. I remember implementing some fixed-point math in my motor control days, but I would have thought that there would be an …

Launch!

Jason Jones — Sun, 31 Jan 2016 20:51:00 -0500

Greetings!

After a number of years of working in the embedded world, I realized that I really enjoy sharing cool things with cool people. This is my attempt to further that goal!