Email to an Anti-Vaxer

I recently had an email conversation with an anti-vaxer. I enjoy critical thinking exercises like this, and thought my response might be useful to publish.

The anti-vaxers key points (I’ve paraphrased here as it was a private email) were:

“An Australian TV program A Current Affair (ACA) screened a segment around a family who was awarded a . . . → Read More: Email to an Anti-Vaxer

Fixed Point Goertzal Tone Detector

This post is a tutorial on fixed point DSP, where I provide a detailed worked example of porting a Goertzal algorithm based tone decoder from float to fixed point.

My post on Fixed Point Scaling is consistently popular. I think that’s because there just isn’t much information out there on fixed point DSP. In particular, . . . → Read More: Fixed Point Goertzal Tone Detector

SmartMic Prototype PCB Ready for Manufacture

Over the past few weeks Rick Barnich KA8BMA has been doing some fine work on the schematic and PCB design for SmartMic. Yesterday Rick and I had a PCB and schematic review meeting over Skype, and Rick is now working on a few small changes. The PCB board layout will go in for manufacture . . . → Read More: SmartMic Prototype PCB Ready for Manufacture

Fluksometer Update

Hello, I am David’s 18 year old daughter, Amy. Some of you may remember me as the girl who’s father busted her teenage party using an energy monitor, from 800km away. Since my social life was destroyed in one night due to this product, I have had a lot of time on my hands. My father . . . → Read More: Fluksometer Update

wxWidgets Checkbox Tooltips

I need to post this so that no one else experiences the same pain with wxWidgets (2.9.4). Tooltips weren’t working for me when I hovered over checkboxes. This has bothered me for about 2 years and Google doesn’t seem to throw up a solution.

We are using wxWidgets for FreeDV, as we needed cross platform . . . → Read More: wxWidgets Checkbox Tooltips

Fixing Broken Plastic Fridge Shelves

I have a small Samsung fridge that developed several cracks in the shelves on the door. After a while the cracks spread and one of the shelves became unusable. We couldn’t seem to buy a spare. This was really annoying. I felt like Samsung was telling me to buy a new fridge! . . . → Read More: Fixing Broken Plastic Fridge Shelves

Electric Car Running Costs

While enjoying a coffee with my 18.5 year old daughter the other day I mentioned a friend’s car was for sale. At only $3,000 it seemed like a good deal. However then we started adding up the costs of running a car. She uses my EV all the time, so we decided to . . . → Read More: Electric Car Running Costs

ST-LINK between two Discovery Boards

I’ve been using the STM32F4 Discovery board for prototyping SmartMic. This board has an ancillary STMF103 ARM3 (U2) that is used to debug the STM32F4 via the ST-LINK interface, which allows me to use gdb, flash the STM32F4 and support semi-hosting for development.

I want to use this same ARM3 to debug SmartMic, i.e. use the . . . → Read More: ST-LINK between two Discovery Boards

Microphone Amplifiers

I’ve been prototyping microphone amplifiers for SmartMic. Although I’m not much on an analog guy I’m getting somewhere. Note the tiny SOT-23 op-amp soldered to a header!

We want to be able to handle electret and dynamic microphones, and have 0 to 40dB gain (trimmer adjustable). Here are the transistor and op-amp versions:

. . . → Read More: Microphone Amplifiers

Introducing the SM1000 Smart Mic

For the last few months Rick Barnich KA8BMA and I have been working on the SM1000, a embedded hardware product that allows you to run FreeDV without a PC. Just plug it into your SSB or FM radio, and you now have Digital Voice (DV). It’s based on a STM32F4 micro-controller, has a built . . . → Read More: Introducing the SM1000 Smart Mic