Sunday, 28 June 2020

I2S microphones on ESP32- how high can it go?

I know it's been a long while since anything got posted - way too long! However, I've been playing a bit with the ESP32 using an I2S digital microphone, and that got me thinking - just how high a frequency can such a microphone actually pick up? To answer that question, I felt I needed to do some digging into how we go from the microphone to a digital signal. I also delved into overclocking a microphone!

Sunday, 22 July 2018

Batteries, PICkit2 and ATmega328 (Pro Mini)

I've had a need to reprogram the fuses on an Arduino Pro Mini clone, as I'm intending to use it on battery power. Running on a couple of AA batteries means the highest voltage the device is going to see is 3v, rather than the 5v the device is expecting. This is going to mean a few modifications in order to make this all work! Just in case you thought that wasn't stacking things up enough, I'm going to be using my PICkit2 to program the Pro Mini clone. 

Friday, 28 April 2017

Carlsbro Suzz / Wah-Wah teardown / minor repair

I recently stumbled on an old Carlsbro suzz / wah-wah guitar effect pedal that I was given at some point in the 1990s. A quick google revealed it doesn't appear to be a particularly common pedal but interestingly it appears the two halves were available as individual pedals and there is a touch more information about them. Anyway, here is my two-in-one.

Thursday, 27 April 2017

H bridges, minor failure and troubleshooting

When I left off last time, I was raring to go with some sample PID code that allowed me to test out a basic movement between two points. I realised I hadn't included any wiring, and that's important for this post. Suffice to say, the code didn't work quite as I had intended, but not for obvious reasons. By that, I mean I spent hours trying to debug what was going on without success. Instead, I had to break out the oscilloscope and measure to find out what was really happening.

Wednesday, 26 April 2017

Motion control - H bridges and movement

In my last post I was talking about getting the feedback mechanism from a printhead carriage up and working. This enabled me to track how much relative movement of the carriage had occurred, but didn't enable me to make the thing move! That comes in this part. In order to get motion happening, I need something that can handle the voltages/currents the motor needs - a job for an H bridge!

Monday, 24 April 2017

Arduino, Motion Control and Encoders

I took a failed Canon Pixma all-in-one inkjet apart in order to see how it was engineered. I also extracted some of the mechanics so I could learn a bit more about motion control in the real world. This post is about that exploration. I was primarily interested in the printhead carriage, as it has a feedback loop to provide information back about the speed of the carriage and which direction it is travelling in.

The printhead carriage itself is little more than some mechanics in the form of a sliding assembly that holds the printhead, a DC motor driving a belt, an optical strip and a pair of optical sensors and an LED.

Thursday, 22 December 2016

TL866 + MiniPro under Linux

I've long been a fan of the extremely useful and affordable TL866 despite its lack of support for a bunch of TSOP flash chips I've recently been looking at.

A mild inconvenience though is the dependency on Windows. For ages I've kept an old netbook around pretty much entirely for the TL866 but I've recently discovered you can run the device quite happily from Linux thanks to the efforts of a couple of guys who've posted their code on github.