Cycling to work in a velomobile

I’ve promised myself to share my experiences with cycling long distances to work once I’ve gone 10 000 kilometres. Sitting on the train right now, it’s a perfect moment to start.

Over the past two years I’ve cycled about 14 000 kilometres to work. My daily commute is 44 km one way, thus doing 88 km every day. Quickly calculated this means I only went 160 times back and forth, or about 8.4 months. Or I was cycling for 480 straight hours, or 20 days non stop.

Doing such a long distance, I only deemed it possible with a velomobile. These low, fast bike machines, make you go faster then ever, trying to ignore the elements like wind, rain & temperature.

Spoiler alert: I sold my velomobile, as, cycling 3h a day, is hard to combine with working a full time job. Injuries are harder to recover from and I felt exhausted after many months of cycling everyday.

What did I like, love and disliked?

Going faster than ever! Mine had electric assist, making it easier to speed up.

The bafang is a great engine, making almost no noise and getting out of the way of the cycling experience. Really feels like going slightly off hill.

Able to maintain high speed and have less issues with wind. Hard side wind however, was sometimes tough to fight.

The visibility is really good as well. Contrary to what many people think, is an object of almost 3 meters long really good to see. The lights of the Waw are also very visible. If I could improve it, I would put the rear light higher and make it brighter. Maybe put in the hood.

The views while cycling the difference can be stunning. Specially when the weather is warm and great! When cold, you still don’t need a jacket. But good winter shoes and socks are a must.

The reactions of people can be strange. I was once followed by a car in a cycling only street. Once she overtook and blocked me, she asked me ‘what the hell I was driving’.

Turning is hell. If you need to go back, you have to step out, and lift the rear wheel by the back. Also, some cycle paths that go op and down, or have posts are not always suitable for driving with a velomobile.

If you come across a crossroads with houses, you really need to lower your speed and cross it defensively. Cycling 45 km/h is not an option.

Showering twice a day can be boring. As well is changing clothes. Even though the electric assist, cycling this amazing bike is very sporty and intense. People often think electric assist is like driving a car. They don’t realise how wrong they are, steering that car.

It was a great experience, but over for me now, as 44 kilometers one way, was 14 kilometers to far. Who knows, maybe in the future?

Using Plex Media Server on a Raspberry PI 3

I am currently experimenting to create a cheap Plex Media Server running on a Raspberry Pi 3!

I am aiming to share my media to my chromecast and my smartphone. So that I can play my music everywhere or turn off my PC when watching a TV Show.

I followed this guide:  https://www.element14.com/community/community/raspberry-pi/raspberrypi_projects/blog/2016/03/11/a-more-powerful-plex-media-server-using-raspberry-pi-3.

Install Raspbian

Raspbian is easily installed! Download the latest lite version: https://www.raspberrypi.org/downloads/raspbian/. At the moment of writing, Raspbian Stretch Lite was used.

On windows, I prefer Etcher to burn the image on an SD card This may help you if you don’t know how to do it.

After loading the image, connect your usb keyboard and hdmi monitor so you can get started with your Pi 3! Now connect the power and see it boot up!

SSH not working?

Already twice I’ve experienced SSH not working with a Connection refused exception in putty.

The problems lies with the host certificate used for ssh and the solution is to remove them and generate them again:

sudo rm /etc/ssh/ssh_host_* && sudo dpkg-reconfigure openssh-server

Ntfs

To use ntfs usb stick I had to install ntfs-3g:

sudo apt-get install ntfs-3g

Then I could use ntfs-3g as a type:

Spin down the hard disk

I tried this guide but unfortunately my old external hard drive doesn’t really support spinning down. I am also not certain if it really ads value.

Let’s install Plex!

Best to begin with updating your Raspbian installation!

sudo apt-get update && sudo apt-get upgrade -y
sudo apt-get update && sudo apt-get dist-upgrade

Install Plex:

sudo apt-get install apt-transport-https -y --force-yes
wget -O - https://dev2day.de/pms/dev2day-pms.gpg.key | sudo apt-key add -
echo "deb https://dev2day.de/pms/ stretch main" | sudo tee /etc/apt/sources.list.d/pms.list
sudo apt-get update
sudo apt-get install -t stretch plexmediaserver-installer -y

Now restart your PI:

sudo reboot

After figuring out your ip, you should be also to surf to Plex: 192.168.0.3:32400/web and register your new server!

Sources

Create a connected temperature sensor with a Raspberry PI

Since the Raspberry PI was introduced in 2012, it’s so much easier to build the Internet of Things! Connecting sensors and exposing the values they read, so much fun!

Time to get our hands dirty! In the coming months, I will stuff my house with sensors to gather data. Motion, temperature, barometric pressure and any other sensors I may come across?

In this post I’ll explain how to connect a digital temperature to a Raspberry PI (1B) and expose this via a NodeJS api.

Prerequisites

Raspbian

Raspbian is the preferred operating system for experimenting with your PI. It’s forked from Debian and is optimized for all the Raspberry PI models. For this project you should download the Lite version, as a GUI is not required at all.

On Windows, I usually create the bootable SD card via Win32 Disk Imager.

SSH

After installing the SD card you can boot the PI. Make sure yours is connected with a screen and keyboard so you can enable SSH (so that you can access it via terminal from another computer).

Login with the default Raspbian user account (pi – raspberry) and enable SSH via raspi-config:

sudo raspi-config

Select Interfacing Options, then P2 SSH, then enable and reboot.

Remote access

Now that SSH is enabled you can access it via Putty. FilleZilla also supports SSH to move files from and on it!

Enabling services

We will also need to enable the I2C interface (to communicate with our temperature chip). You can easily do this with raspi config:

sudo raspi-config

Select Interfacing Options, then P5 I2C, then enable.

Install the sensor

Now to fun part! Connecting the Sparkfun TMP102 with your PI!

Raspberry Pi TMP102
3v3 Power VCC
Ground GND
SDA SDA
SCL SCL
Ground ADD0

Make sure to connect the correct pins on your Raspberry PI, by googling the pin layout of your Raspberry PI! This is how mine looks:

Read the sensor data

The following Python script will read the temperature (in Celcius) and print the value to the terminal.

tmp102.py

#!/usr/bin/python
import smbus

I2C_BUS = 1
bus = smbus.SMBus(I2C_BUS)

# 7 bit address (will be left shifted to add the read write bit)
DEVICE_ADDRESS = 0x48

# Read the temp register
temp_reg_12bit = bus.read_word_data(DEVICE_ADDRESS, 0)
temp_low = (temp_reg_12bit & 0xff00) >> 8
temp_high = (temp_reg_12bit & 0x00ff)

# Convert to temp from page 6 of datasheet
temp = (((temp_high * 256) + temp_low)>>4)

# Handle negative temps
if temp > 0x7FF:
 temp = temp-4096;
temp_C = float(temp) * 0.0625
print "%3.2f" % (temp_C)

If you want to execute it, first mark it executable:

chmod +x tmp102.py

And now:

./tmp102.py

Create the api

Install Node.js

We’ll be using Node.js to display the temperature over an api!

Install Node.js:

curl -sL https://deb.nodesource.com/setup_7.x | sudo -E bash -
sudo apt install nodejs

See if it’s installed and the version:

node -v

Add the Node.js files

package.json

#package.json
{
 "main": "index.js",
 "author": "Elias Lecomte <elias.lecomte@gmail.com>",
 "dependencies": {
  "express": "^4.14.1"
 }
}

And an Express app:

server.js

"use strict";

const http = require('http');
const express = require('express');
const exec = require('child_process').exec;
const execSync = require('child_process').execSync;

// Express app
const app = express();
app.get('/', (req, res) => {

// Get raw temp data
 let tempRaw = execSync(__dirname + '/tmp102.py').toString();

// Parse raw temp data
 let temp = parseFloat(tempRaw.split('\n')[0]);

// Response
 res.json({
 temperature: {
 value: temp,
 description: 'Temperature in Celcius'
 }
 });
});

app.listen(80);

Now let’s download the required dependencies:

npm install

We can now start our Node.js app:

node index.js

You can now see the results by surfing to the ip (when you are on the same network):

Make it start at boot

The last bit. We want to start our Node.js api when the Raspberry PI boots. I found the easiest way to add the startup command to /etc/rc.local.  This script is run at the end of the boot cycle.

su pi -c 'sudo node /home/pi/server/server.js < /dev/null &'

Now just reboot your pi (sudo reboot -n) and your Node.js app should start when the boot is finished! Enjoy!!

Sources

Raspbian cheat sheet

My own cheat sheet for commands I often use. It’s a work in progress.

See CPU Temperature
/opt/vc/bin/vcgencmd measure_temp
List hard disks
sudo blkid
Reboot
sudo reboot -n
Shutdown
sudo shutdown -h now
Upgrade your installed packages
sudo apt-get update
sudo apt-get upgrade
See available disk space
df -h

Detect motion with a Raspberry PI

It’s relatively easy to detect motion with a PIR sensor connected to your Raspberry pi’s GPIO.

This is merely an overview of how to write the python script. For more details on how to connect the sensor, read this.

When you have Python V2 you can follow this, check with python -V.

sudo apt-get update
sudo apt-get install python-gpiozero python-pkg-resources python-dev

Now that you have all dependencies you can create a python script like:

#!/usr/bin/python
from gpiozero import MotionSensor

pir = MotionSensor(4)
while True:
    if pir.motion_detected:
        print("Motion detected!")

Or you could just print if there is motion once:

#!/usr/bin/python
from gpiozero import MotionSensor

pir = MotionSensor(4)
print pir.motion_detected

Now make the script executable:

chmod +x script.py

Now you can execute the script:

./script.py