twiddling bits and atoms

From zero to SoC in LiteX

twiddling bits and atoms — Sat, 22 Aug 2020 22:47:00 +0300

Recently I had a need for microcontroller with larger than usual number of peripherals and found that none of STM32s have the number of peripherals I wanted, so I decided to do a small feasibility study on building my own using LiteX.

This article details the sequence of steps I …

Deployable convolutional neural network libraries

twiddling bits and atoms — Thu, 23 Feb 2017 00:00:00 +0200

I recently reviewed the current state of neural network libraries from a perspective of integrating them in multi-platform, desktop C++ applications (Linux, Windows). Although there has been a lot of progress in machine-learning, it mostly seems to be concentrated on the research/development side. As a consequence, deployment of the …

Machine learning on other people's computers

twiddling bits and atoms — Thu, 09 Feb 2017 21:30:00 +0200

Recently I've been experimenting with machine learning models for image recognition tasks (convolutional neural networks, CNN).

The training phase of the machine learning requires a whole lot of floating point operations. Even though current generation CPUs are really good at number crunching, their performance is still not enough- GPUs outperform …

An overview of RaspberryPi cameras

twiddling bits and atoms — Wed, 11 Jan 2017 20:00:00 +0200

RPi is one of the most interesting SBCs for small, self-contained image recognition applications. In this post, I will explain why I think this is the case and present an overview of cameras I have tested on RPis.

Why RPi?

RPi is not the only SBC around. Some of them …

MAVLink wireless bridge (MAVBridge)

twiddling bits and atoms — Sun, 04 Dec 2016 20:00:00 +0200

I have been using MAVLink on various flight controllers for ~ 2 years now and one thing that made me mad was lack of high bandwidth wireless connectivity between PC and airborne platform.

The most common wireless options for MAVLink are RF transceivers operating in ISM bands and Bluetooth SPP (serial-port-profile …

Upping STM32 debugging

twiddling bits and atoms — Thu, 24 Dec 2015 01:34:00 +0200

Lately a major part of my day job has been writing software running on STM32 microcontroller. Up until this point my only debugging tools were limited to:

printf-littering code and looking at output in serial console;
Stepping through code with debugger (gdb together with OpenOCD or stlink);

Both of the …

Using Dynamixel's RoboPlus without USB2Dynamixel

twiddling bits and atoms — Fri, 07 Nov 2014 00:00:00 +0200

Recently I needed to debug Dynamixel's MX-12W smart servo motor which didn't work in multi-turn mode.

Having exhausted all other options (reading datasheet carefully, probing data line to verify that MCU sends what I think it should send), I decided to try moving the motor using Dynamixel's RoboPlus software.

Usually …

My take on a custom laptop

twiddling bits and atoms — Tue, 19 Aug 2014 22:48:00 +0300

Inspired by bunnie's Novena, I decided to build my own customized laptop with focus on experimentation with hardware.

My main motivation for this project was that I got tired of lugging around devboards, USB UART bridges half-assembled projects. Also, I'm usually a bit concerned about my soldering skills and EE …

TV-OUT on Olimex's A10-LIME

twiddling bits and atoms — Tue, 01 Apr 2014 17:50:00 +0300

I got my hands on Olimex's new A10-OLinuXino-LIME as a potential replacement for RaspberryPi which I fried by accident. One specific requirement I had was a composite TV output (PAL/NTSC). It is not mentioned anywhere in product briefs by Olimex, but this SBC does have an analog video output- …

Combating endstop noise on a RepRap

twiddling bits and atoms — Thu, 06 Mar 2014 13:26:00 +0200

While assembling my new toy - a larger, RepRap-based 3D printer, I experienced strong noise on endstop inputs.

Endstops on my machine are pure mechanical switches, and the wires to endstops are in the same cable where wires to stepper motor are (unshielded, of course).

I wasn't surprised to see some …

Using pcb2gcode with Marlin/grbl firmwares

twiddling bits and atoms — Wed, 14 Aug 2013 12:38:00 +0300

Recently, I wrote about building a small CNC machine. I started to modify pcb2gcode, so that it is usable with Marlin/grbl type of CNC controllers (which, admittedly, support only a basic subset of proper G-code commands).

Mainly, my issues were:

Marlin did not support imperial units.
Marlin did not …

Homemade desktop CNC router

twiddling bits and atoms — Tue, 30 Jul 2013 23:17:00 +0300

During the last few months I have slowly been building a desktop CNC router. It is loosely based on Pleasant Mill by Zaggo, which in turn is loosely based on famous Mantis mill.

I changed some parts of Zaggo's design to my liking:

I wanted an enclosed work area, so …

CarPC build part 2: hardware, still

twiddling bits and atoms — Sun, 02 Jun 2013 23:38:00 +0300

This is the second part of building a RaspberryPi powered CarPC. I ended previous entry with seemingly nice photos of home etched PCB of hardware revision 1. Unfortunately, things did not go as planned, and I had to derail this project a bit.

After careful inspection of rev 1 PCB …

Scanning laser projector

twiddling bits and atoms — Wed, 15 May 2013 00:00:00 +0300

Preface (or, Why?)

In the meantime while I gather enough courage/dedication to finish the projects I have started (e.g. master's degree, carpc build), I wanted to share what else I have been working on.

It all started with an idea about SLS 3d printer, using light-curing resin and …

Compiling code for Stellaris Launchpad with TivaWare

twiddling bits and atoms — Sun, 14 Apr 2013 14:15:00 +0300

So, half a year has passed by since I received Stellaris Launchpad kits from Texas Instruments. I just could not resist the temptation to get two of them for $5 each and I might just have found an application for them. Okay, let's write some code.

Wait, I have no …

Meta-post

twiddling bits and atoms — Wed, 02 Jan 2013 14:03:00 +0200

This is a post which briefly describes why I have moved on from Drupal to managing my static file with the help of pelican.

Since I'm writing so rarely, it didn't make sense for me to often go through the pain of upgrading Drupal and all it's countless modules.
I …

CarPC build part 1: hardware

twiddling bits and atoms — Sat, 29 Dec 2012 16:46:00 +0200

This is the first part of building a RaspberryPi powered carpc.

Over a course of few months (been busy with, eh, life) I've designed the first iteration of custom Atmega-based circuit which lets me interface with car's electronics.

The main part of schematics (pdf)

Second page with power supply and …

RaspberryPi powered car-pc

twiddling bits and atoms — Fri, 28 Dec 2012 00:00:00 +0200

Why?

Some time ago, I got myself a Raspberry Pi. Initially it was supposed to replace my home-theater PC but I found it's too slow. So, I had a problem- what to do with such a nitty device of Pi.

This was not the only problem I had- my old …