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

Scatter Plots and FreeDV

I’ve been prototyping parts of SmartMic (more on that later), for example the interface between the micro-controller and the radio microphone input. I have been using FreeDV as a test tool to evaluate the quality of the signals passing through my prototype circuits. As I worked I recalled a conversation with Mel Whitten. He . . . → Read More: Scatter Plots and FreeDV

Charging Strange Camera Batteries

I borrowed my Mother’s camera once, and somehow lost the special charger. So now every few months she brings it around and I have to work out how to charge the little Lithium battery. This usually involves fiddling with bits of wire, a current limited bench power supply (4V, 100mA), and a vice or . . . → Read More: Charging Strange Camera Batteries

My Vacuum Pump Won’t Stop!

The brake pump in my EV has been acting up. In an EV the brake pump provides vacuum to run the power brakes, as the original source of vacuum (the internal combustion engine) has been removed. I have mine connected to a little vacuum switch (bottom of photo with screwdriver adjustment) that turns the . . . → Read More: My Vacuum Pump Won’t Stop!

Natural and Gray Coding

After writing up the Variable Power Quantiser work I added another function to my fuzzy_gray.m Octave simulation to compare natural and Gray coded binary.

Here are some results for 3,4, and 5 bit quantisers over a range of errors:

Curiously, the natural binary results are a little better (about 1dB less Eb/No for the same SNR). Another . . . → Read More: Natural and Gray Coding