ROS experience

ROS on raspberry pi There is a compiled image for RPi by ubiquity that has ROS kinetic: It seems for me too old. It’s 2020, there are ubuntu 18, ros melodic and ros2, next year the support of python2.7 will be discontinued. Meh… It is possible to have ROS melodic on Raspberry Pi 3 B+. See in the next sections. Installing tensorflow for ROS on raspberry pi Alternatively one can try to install it from wheels: https://www....

August 24, 2019 · SergeM

Arduino Experiments

Arduino board Arduino Nano v2.3 manual (pdf) Arduino and shift register 74HC595 74HC595 Datasheet (pdf) 74HC595 Explanation Youtube tutorial with buttons: Tutorial with arduino - I was using that. My version on a breadboard: Code: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 //the pins we are using int latchPin = 2; int clockPin = 3; int dataPin = 4; void setup() { //set all the pins used to talk to the chip //as output pins so we can write to them pinMode(latchPin, OUTPUT); pinMode(clockPin, OUTPUT); pinMode(dataPin, OUTPUT); } void loop() { for (int i = 0; i < 16; i++) { //take the latchPin low so the LEDs don't change while we are writing data digitalWrite(latchPin, LOW); //shift out the bits shiftOut(dataPin, clockPin, MSBFIRST, i); //take the latch pin high so the pins reflect //the data we have sent digitalWrite(latchPin, HIGH); // pause before next value: delay(50); } } Alternatives More powerful shift register: TPIC6B595 PWM: TLC5940, TLC5947 PWM with i2c: PCA9685, PCA9635 PWM via shift register PWM Through a 74HC595 Shift Register at forum....

July 14, 2019 · SergeM

Reducing disk usage in Ubuntu

Here are some recipies to make ubuntu installed on USB drive to work faster. [1] [2] reducing swapping Add these lines to /etc/sysctl.conf, and reboot. vm.swappiness = 0 vm.dirty_background_ratio = 20 vm.dirty_expire_centisecs = 0 vm.dirty_ratio = 80 vm.dirty_writeback_centisecs = 0 More caching while writting on disk Add noatime,commit=120,… to /etc/fstab entries for / and /home

August 16, 2018 · SergeM

Ubuntu/linux settings

Some settings I find useful for a workstation CPU monitoring on the main panel Default Ubuntu desktop seems to become finally convenient enough for me starting from Ubuntu 18.04. Only several tweaks are missing. Constantly available CPU/Mem/HDD/Network monitor is one of them. Here is how to install a small widget for a top panel in the default GNOME desktop environment. sudo apt-get install gir1.2-gtop-2.0 gir1.2-networkmanager-1.0 gir1.2-clutter-1.0 Go to Ubuntu Software and then search for system monitor extension....

January 11, 2018 · SergeM

Set up HP 1020 printer in Linux Mint 18 / Ubuntu

Using open source drivers Follow the instruction from or use my clone on git Clone the repo git clone foo2zjs cd foo2zjs Compile: make Get extra files from the web, such as .ICM profiles for color correction, and firmware. Select the model number for your printer: ./getweb 1020 # Get HP LaserJet 1020 firmware file Install driver, foomatic XML files, and extra files: sudo make install Configure hotplug (USB; HP LJ 1000/1005/1018/1020)....

January 9, 2017 · SergeM

Shell commands (page moved)

Page moved here

January 8, 2017 · SergeM

linux life

Good start 1 sudo apt install -y mc curl jq wget htop hwinfo nmap vim Some commands top - see running processes df - check free disk space baobab - free disk space screen - multiple virtual consoles in one real [ref], need installation in ubuntu mc - file manager ccsm - disabling smooth fades and animations (speedup interface, especially useful in VirtualBox) sudo apt-get install compizconfig-settings-manager then ccsm Set up SFTP server How to set up an SFTP server on Linux - some commands are broken (wrong paths and users) but in general works See also more here Ubuntu customization: ubuntu-linux-settings Mount windows shares in linux

June 2, 2014 · SM!