esorensen.com

Denmark

Denmark: Amplifier Module

This post summarizes the build of an ICEpower-based 3-channel amplifier with DSP crossovers.

cnc

CNC Mill Update - 2023

In this update post I will describe a few of the modifications and improvements I’ve done to the mill. I occasionally get emails requesting information about modifying the mill and I hope this post will be helpful for anyone else working on a benchtop mill.

3dprinted Featured

Coffee Roaster Controller Intro

In this post I will document the build of my air popper controller to roast quality coffee. I am providing enough detail that someone interested should be able to replicate the project. If you are working on building your own and run into any issues please reach out!

Coffee Roaster Conclusion and Results

On this page I wrap up the project by covering a few open items. I summarize the experience using the roaster and lay out some future opportunities.

coffee

User Interface and Firmware

This page gives a high level overview of the user interface design of the coffee roaster. I discuss the management of responsibilities between the Nextion display and the Arduino controller and summarize the UI elements.

embedded

Building the Control Board

This pages summarizes the bill-of-materials and schematic for the coffee roasting controller. Wiring up the controller is pretty straightforward and follows directly from the schematic.

roast

Modifying the Air Popper

This page shows the process of modifying a Poppery II popcorn popper so that the motor and heater coils can be operated independently of each other. During the modification a thermistor is added to monitor the temperature of the coils and a thermocouple to monitor the chamber temperature.

speakerbuild

Bookshelf Speakers + Mini Subwoofer

This is a build log for a custom set of speakers I built for a friend. I made a subwoofer similar to the "Voxel" design from Paul Carmody. I made it slightly larger, increased the port diameter, tuned slightly lower, and added a Lepai plate amplifier. I am *very* impressed

astronomy

Photo of Comet Neowise

Made it over to Mt. Hood to see Comet Neowise and captured this photo. The Portland city lights are visible on the horizon.

hamradio

Home Antenna Grounding

I recently installed an end-fed wire antenna running from the apex of my garage into a large maple tree in my backyard. I want to get the best performance I can from the antenna and also take the appropriate precautions to operate safely and protect my equipment.

Yeasu FT301D Restore - Part 1

When I first got my ham radio license I purchased a Yaesu FT-301D from another amatuer radio operator on Craiglist. I enjoyed using the radio, but over the years I've ended up using other radios that were either more reliable or matched my requirements better (QRP, portable, etc). At this

retrogaming

MiSTer Case

I've recently been interested in FPGA-based gaming systems. These systems implement the hardware of gaming systems on a programmable FPGA to achieve very accurate "hardware emulation" of the platform. A recent popular example is the Analogue Pocket, which is an FPGA-based handheld gaming system which can interface with Gameboy and

hamradio

Loop Antenna Copper Jumpers

I am planning to machine some copper jumpers to go between the copper loop and the vacuum capacitor. These can be soldered (or brazed) to create a solid connection with very low resistance.

3dprinted

D&D Miniature and Dice Holder

As a Christmas present I hired someone on Fiverr to create a 3D model based on the image and I 3D-printed a couple of custom miniatures. I also created a wooden dice tray and miniature holder for storage out of walnut.

cnc

LCD Control Board for SX3 Mill

The LittleMachineShop control board replaces the button board built in to the mill, so when the spindle control board is connected the buttons and LCD built in to the mill are no longer functional. I designed a drop-in replacement for the button board to help add back some functionality.

hamradio

Full Disk Images of Earth from GOES-17

Geostationary satellites maintain their position relative to earth. This means a parabolic dish can be pointed at the satellite and receive continuous downloads.

photography

Astrophotography, Part 1

Astrophotography used to be a hobby of mine and I would make it out with my camera a few times a year. Over the last few years I haven't prioritized this hobby, but I am ready to start again. Astrophotography typically involves hours of idle time in remote locations (often

photography

Soap Film Photography

After a few photo and brainstorming sessions, we ended up with a repeatable setup to capture the kinds of images we wanted. In this post I hope to pass on some of the things we learned and share some of the resulting images.

loopantenna

Loop Antenna - Initializing the TMC2130

Continued from part 4. Now that I can read and write across the SPI interface I am going to write an initialization routine for the TMC2130. Fig 22.1 and 22.2 in the TMC2130 datasheet show a "quickstart" routine for the TMC2130. First, here is 22.1: At "SC2"

STM32

Loop Antenna - SPI Read and Write

Continued from part 3. Now that I have confirmed the stepper driver is working properly, I want to establish SPI communication for configuration and status readback. This will be especially important to enable the stall detection feature I am using for homing. First, I wrote a function to read and

hamradio

DDS RF Signal Source

In 2017 I designed a local oscillator board which can be used to generate an RF signal in the HF range (< 30MHz). I hope that this can become the building block for a more complete radio design, so I included a lot of expansion options including an I2S interface, I2C,

cnc

Shopfox M1111 Mill Conversion - Intro

In 2017 I acquired a Shopfox M1111 benchtop mill. It has an intermittent issue with the spindle motor, but is otherwise mechanically sound. This mill is very similar to the Grizzly X3 mills and is suitable for light-duty milling in aluminum. Leadscrews These mills are commonly converted to CNC machines

loopantenna

Loop Antenna - Motor Control Part 1

Continued from Part 2. I am starting to work on the automatic tuner for the magnetic loop antenna. I will implement the various functional blocks in the following order: 1.    Motor control and homing 2.    SWR measurement 3.    Seeking algorithm to store history and tune quickly Component Selection: I am

loopantenna

Loop Antenna - Assembly and First Test

Picking up from part 1. Today I finished assembling the loop antenna and ran some tests on it for the first time. The results look great so far and after this I'll be ready to put it on the air. First, I screwed on the plastic clamp pieces to each

Oddwatt Amplifier Assembly

In 2016 I built a sound system including speakers, preamplifier, subwoofers, and amplifier. I chose a tube amp design based on the "Oddwatt" design  by Bruce Heran. If you want your own tube amplifier design, I highly recommend checking out his website here. Bruce is very helpful and active on