Tag Archives: RaspBerry Pi

Raspberry Pi: Solving the problem GPIO.setup(self.number, GPIO.IN, self.GPIO_PULL_UPS[self._pull]) RuntimeError: Not running on a RPi! in Ubuntu 20.04LTS

So you are trying to program the Raspberry expansion PINS in Python, for example for this 3D LED Christmas Tree, and you’re getting the error:

GPIO.setup(self.number, GPIO.IN, self.GPIO_PULL_UPS[self._pull])
RuntimeError: Not running on a RPi!

I’m running this on Ubuntu 20.04LTS with a Raspberry 4.

The first thing:

Make sure you have an official Raspberry Pi charger.

Or at least, make sure your USB charger provides enough intensity to power the Raspberry and the LEDs.

The LED power comes from the motherboard and if Raspberry Pi has not enough energy this is not going to work.

My colleague Michela had her tree not working because of the charger was not able to provide enough energy. When she ordered a new charger, it worked like a charm.

Install the base Software

In order to communicate with General Purpose Input Output ports (GPIO) you need to install this Software:

sudo apt install python3-pip python3-gpiozero
sudo pip3 install giozero

In order to run the 3D LED Christmas Tree code samples

sudo pip3 install colorzero
sudo pip3 install rpi.gpio --upgrade

Reboot

It may be not required in some cases.

Download the Source code

https://github.com/ThePiHut/rgbxmastree#rgbxmastree

Run the samples as root

I saw many people stuck, in the forums, because of that.

To work with the LEDs you need to run the samples as root.

Some code examples

To provide a bit of “the whole package” here are some simple examples.

Turn to red the LED’s one by one

from tree import RGBXmasTree
from time import sleep

o_tree = RGBXmasTree()

for o_pixel in o_tree:
    o_pixel.color = (1, 0, 0)
    sleep(0.1)

Turn to a different color, sleep, and again

from tree import RGBXmasTree
from time import sleep

o_tree = RGBXmasTree()

a_t_colors = [(1, 0, 0), (0, 1, 0), (0, 0, 1)]

for t_color in a_t_colors:
    o_tree.color = t_color
    sleep(1)

Turn off the lights

from tree import RGBXmasTree

o_tree = RGBXmasTree()

o_tree.color = (0, 0, 0)

Where I used it?

I used it in my Open Source monitor Software CTOP.py in order to show the plugins/extensions capability of it. :)

What is PrototypeC and how you can DIY

It all started with my best friend, and the best Engineer I know, E. H. We often meet for doing hackatons and we explore node, go, patterns, technologies… Some times we just meet and improvise a hackaton.

I’ve been carrying with me a laptop, almost every single day of my life, since many years ago (that’s why I created some jokes about gym and IT and have fun with my friends, like: we IT guys go to the gym to be so strong so we can carry a laptop everywhere, all the time, without effort).

But some of my friends suffer from the back, and they can’t carry weight, so they don’t bring with them the laptop unless necessary.

There are some other friends, Sysadmins in the Operations field, that sometimes have alerts, so they have to carry a laptop with them when they’re on guard, but sometimes they have an alert out of guard, and nobody else can fix it and they don’t have a computer with them.

I also I’m concerned about privacy and sadly most smartphone builders install crappy Software that spy the users, and send keystrokes to third party companies, etc… So having a portable device, small as a credit card, where you can type your business ideas or your thoughts with some privacy, or you can use to fix remote servers when they broke, etc… looked appealing. This also fits with my private messenger c-client.

So, when I configured my raspberry 2 with OSMC and started to install Software, program crons, etc… I realized that is a tiny computer, capable enough. And then an idea came to me.

What if I can make this lightweight motherboard a wearable computer?.

And I started to play with this.

OS

I first needed an interesting enough OS, that I or my DevOps friends would like to use.

I choose Debian Jessie for Arm (armhf). Raspberry Pi 2 uses ARM v7 that is a very important improvement respect previous Raspberry models, not only in performance, but also in the floating point. That simplifies many things and much more Software packages are available (like Snappy Ubuntu Core or Windows 10).

Using Debian Jessie provided me with a very basic system that really uses few RAM memory. It uses only 65 MB RAM, with all the Wifi supported firmwares.

Then I installed X-Windows, with LXDE as Desktop Manager. Everything uses only 120 MB RAM.

I installed several packages, to highlight the epiphany web browser, Open Java Runtime Environment, and PHPStorm IDE.

I also use Ubuntu 15.04 Desktop for ARM.

Battery

Unless Raspberry pi first generation, Raspberry Pi 2 uses micro-USB standard 5V input, like most of the Android phones. So I decided to do some tests about sustained energy input with batteries.

First I calculated the energy consumption of the Pi 2, plus Ethernet and plus some USB devices I would like to attach.

I found that common power banks, those you use to charge your smartphone when battery is depleted and you’re on the run, bring a continuous energy signal that works perfectly well. I tested it by running the Raspberry Pi 2 for hours while reproducing video, doing live updates, flawlessly.

Then the first version of the Prototype C was born.

Costs:

$40 Raspbery Pi 2
$10 Powerbank 2000 mAh
$15 USB Wifi-N card

It weights 160 grams/0.3527 pounds/5.64 ounces.

Some of the powerbanks are so cool that they allow you to charge them while at the same time they are providing energy to the output. So you can have the Prototype C continuously running, and if the battery is going to deplete you can just plug it to the energy plug of a bar, and the C will continue running non-stop, and the battery will charge, so in a while you can continue your walk without stopping the C.

Later I bought a Levin solar powered battery, that is lightweight, protected to impacts and that has two outputs (1, 2 A) and charges while exposed to sun, so I can have the battery in the outside of my bag, and while I walk in the city it is being charged at a max rate of 200 mA. This is ideal for people hiking in the mountain or traveling in the world, so it can save lives if a problem comes and phone’s battery is depleted.

I think also in boys in Africa or poor countries where they children have to walk a long to the school. This walking could help charging the battery so they can study at the school and continue studying at home.

With the C a solar powered battery also allow to blog from everywhere. :)

You don’t even need a cable, just an small USB-micro-USB connector

Note: This Levin solar battery doesn’t accept to be charged and to bring energy to the device at the same time.

Note: you can also aliment it from the car lighter connector with and adapter.

Monitor

That part is not easy.

The monitors I was interested in were not sold to Catalonia. Finally I was able to find some of my interest in Amazon.es

Most of those monitors work for the Raspberry Pi, first gen, or for Arduino, Banana Pi, etc… but not for Raspberry Pi 2. So this is the first thing to be careful.

Other of those monitors get the signal from the Raspberry Pi GPIO, the General Purpose Input Output, from Raspberry. So they need some kernel patching, binaries, not Open Source code usually, and that also prevents from certain kind direct access to drawing in X not being displayed in the monitor attached via GPIO.

Other monitors require external power source, often 12 V, and so are very voluminous. So they are not a fit for our means.

Normally those monitors are touch screens, some take the power from the GPIO and also control the touching from there, but others require two USB: one for the energy and other for the touch controlling part.

You have also to consider if they have external button to power on, power off.

Also those monitors have extremely low resolution, 320×480 and like this. Only found a model supporting 800×600 and is a 5″.

And finally you have to take in consideration the power consumption.

I solved this by buying power banks that have a 2 or 2.5 A output.

Simple power banks provide a 1 A output, better ones provide two outputs: 1 A output for smartphones, and 2 A output, normally for tablets.

Part of the cool thing is the possibility to have the monitor in a place, and the Pi and the battery in another place, like for creating wearables and other cool stuff.

As I wanted to provide DIY for people, and an elegant cheap lightweight solution, the difficulty to find those monitors was a gap, so I explored several ways to use cheaper screens until I realized what is what every engineer (and common people) carries with him every day?. The smartphone.

USB Wifi

As I wanted to have Wifi I needed USB Wifi that can work with Raspberry Pi 2 and Debian Jessie.

I had some problems at the beginning (caused by a bug in wcid), but I managed to make everything work. I have made it work with two different Wifi card models flawlessly: TP-Link Nano, Asus Nano USB-N10.

Nothing stops you from adding two Wifi USB to the device. In fact is my preferred option, as I use one for being connected/controlled/display to the phone, and another for connecting to the Wifi of the place I am. That way I don’t use my mobile Data plan that much when I’m outside. In this case I recommend to use different cards (different supported chipsets) to save you headaches configuring and setting what does what (unless you like to fight with configurations until you master everything :).

Some USB Wifi devices also equip Bluetooth transmission, that is very interesting for future prototypes for controlling other devices (car radio, headsets, commands..).

Controlling the C from the smartphone

I started to test certain things to overcome the display difficulties and finally I had cool an idea and I found a very nice option.

Here configuring the Vnc client to access to :1

Sharing the Internet from my iPhone creates an internal network of the type 172.20.10.x.

Sharing the Internet connection from the phone, and connecting the C automatically it creates a private network, with full network visibility between the devices.

So with a ssh app for iPhone like Server Auditor I was able to connect through ssh to the C, and with a VNC Client, like Real Vnc Client, I was able to connect to the Desktop of the Prototype C, control it, send keystrokes, zoom in, zoom out. Both apps are free to download and to use.

For Android it works the same, for sharing the Internet connection it creates an internal network with another range and there are also free apps for the purpose.

The ip assigned is normally the same, 172.20.10.9 in my case.

The only required thing was to setup the C to auto-connect via Wifi to my phone’s Wifi shared connection, and then connect to the C device’s ip.

This is very easily done with Wcid from LXDE.

Mark Automatically connect to this Network

I configured vnc server so I can access to the same display than the HDMI, so I can switch from working with the smartphone to HDMI easily, and I also configured vnc server through other display at a 1024×768 resolutions. That was more comfortable to work only with the small screen of my iPhone 4. Although setting a lower resolution, like 800×600, makes it easier to work with tiny screens.

With the Vnc client you can zoom in, zoom out, with the classical gestures and use keyboard.

Not only this, I allowed several of my friends to have their own independent sessions to the same C. So with only one C several Engineers can Develop or do DevOps stuff.

Must say that with the Nexus and other smartphones with bigger screens, or tablets, the experience is amazing, much much better than with my tiny iPhone’s 4 screen.

And of course you can control the C also from a laptop.

Nailing it

I added to the set an external bluetooth keyboard+touchpad.

Prototype C with the bluetooth keyboard. The motherboard is hidden under the battery

If you use VNC on display :0 it’s perfect, obviously external keyboard won’t work if you use different displays (as key strokes are sent only to the device and not to the different X VNC sessions, of course).

With an external keyboard, the worries about spyware in the iPhone were mitigated, as all the keystrokes are on the physical external bluetooth keyboard and not on the iPhone’s screen.

The C with a smaller battery

I used a Rii mini i8, and a Logitech.

Some photos of real use examples

Sometimes I just connect the raw motherboard to the solar charger in the bag and only use the smartphone over the table.

Sometimes I just connect the raw motherboard to the solar charger in the bag, and just use the smartphone over the table.

We were dinning and to the cinema with some IT friends when suddenly one of the SysAdmins got an alert and needed a Linux box

We were dinning and to the cinema with some IT Engineer friends when suddenly one of the SysAdmins got an alert and needed a Linux box

No space? Do you need a sand box and have no memory for a virtual one?

Opening PHPStorm at the bar. Under LXDE

blog-carlesmateo-com-web-browsing-at-the-bar

The C at the bar displaying epiphany web browser with the address http://www.prototypec.com

C over a jacket in a restaurant

Waiting time? Get C!

Mounting a USB mini webcam in a glass, while at a bar. The battery is charging the iPhone and powering the Prototype C

Honestly, I love to carry with me the raw Raspberry Pi 2 motherboard (in a cartoon box) and to connect it as is, but you can use a plastic box. It is also very useful to hang to walls, furniture, or the car.

Raspberry Pi and osmc

There is something that fascinates me from the new Raspberry Pi, and using it as a media center.
It is the fact that is a really small board.
That is powered by a micro USB 1000 mhA.
That is powered with Linux.

I had other media centers before but they were magnetic hard disk, closed in a proprietary system.
The media center I installed, with RaspBerry Pi+, is osmc, that is Open Source Media Center.

So I have full access via ssh to the RaspBerry, and as it used so few energy I have it all the day up.
Then, as it is a Linux box, and I have full access, and I’ve around 546 MB RAM free, I can run as many background process as I want.
Do I want to be a jump point for my VPN? Let’s go.
Do I want to have some monitoring processes over few websites? Let’s do it!.

I’m really happy about having a so tiny, so few energy consuming, full Linux, being my media center and whatever I want to it to do.

I must say that is wonderful having SSH and a network interface. Ok, it’s 10/100 Mbps, not Gigabit, but it is enough to allow me to copy new files in background to the USB stick via SFTP while reproducing at FullHD Blueray MKV, files right. Also allows to mount network folders via NFS or SMB amd play from them. Copying via SFTP to the USB device is generally very slow -don’t be surprised to upload at 30 KB/s- so I recommend to set a NFS folder in the computer, with read access to the ip of the Raspberry. It’s very cool and plays totally smooth using the 100 Mbit ethernet connection. You can also configure a FTP in the Pi, that will be much faster than the SFTP.

The RaspBerry micro SD card has a performance of ~22 MB, that is enough to boot very quickly and to load programs quite fast. I have other microSD cards with Debian Jessie, and I load PHPStorm (Java based PHP IDE) quite fast.

It boots really fast, in case you stop and start it frequently.

It accepts my wired Mouse and Keyboard, and also wireless bluetooth.

I’m really in love with this small motherboard. :)

This tiny RaspBerry 2, has 4 cores at 900 Mhz.

The CPU announces (cat /proc/cpuinfo):

processor    : 3
model name    : ARMv7 Processor rev 5 (v7l)
BogoMIPS    : 38.40
Features    : half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt vfpd32 lpae evtstrm
CPU implementer    : 0x41
CPU architecture: 7
CPU variant    : 0x0
CPU part    : 0xc07
CPU revision    : 5

As you see, it scores only 38.40 bogomips, compared to my tower desktop 6384.59, and my old laptop 2593.45, but it’s still beautiful.

Note: you cannot trust bogomips as a performance measurement, and in addition my computers are Intel based -so CISC architecture- while RasbBerry uses ARM processors that are RISC, that is a completely different architecture. I notice a very fluid speed, only I sense a bit slowliness in the process when I install new packages. When unpacking it feels slow, although it can perfectly be caused by the SSD card IO as well, so I installed iotop and monitorized the I/O while I was installing PHP5 :) . I got small writings up to 1,000 KB/sec, so 1 MB/s, with average of ~30-50KB writing operations, no iowait, while I was seeing with htop that the core unpacking was at 100 % of CPU, the other 3 were free, so my initial conclusion is that the bottleneck was on the CPU. Still happy about my little gadget. :)

The osmc image I installed comes with python 2.7.9 and Linux kernel 3.18.9 as uname -a shows:

Linux osmc 3.18.9-5-osmc #1 SMP PREEMPT Wed Mar 11 18:59:35 UTC 2015 armv7l GNU/Linux

It also comes with wget 1.16 and curl 7.38.0.

In fact the OSMC is based on the Debian Jessie distro.

The OSMC software also have upgrades, and Debian upgrades, that keep the Linux box up to date.

So that brings a lot of possibilities.

After a sudo apt-get update I was able to install htop, mc and apache2.

sudo apt-get install htop
sudo apt-get install iotop
sudo apt-get install iftop
sudo apt-get install mc
sudo apt-get install apache2
sudo apt-get install php5
sudo apt-get instlal ncdu

So it’s a lot of fun. :)

Note: Although a 1000mhA is enough (Raspberry Pi 2 needs around 700mhA) if you plan to plug a cheap case 2.5 hard disk without external power -just USB- it will not be enough. In this case I recommend buying a 2000mhA transformer for the Pi, or a external USB hub energy powered (2000mhA otherwise you risk energy from Raspbery + USB hub being to sufficient). If the disk has external power, then you’ll have no probem. Personaly I use USB sticks.

When I had my incubator of Start ups some years ago, one of my Start up project was embedding motherboards within screens, and offering the ability to play videos, images, even flash games and animations, and manage and update everything and update contents for a groups of players from the Internet, or based on time triggers. I was finalist for selling my product to a enormous multinational, it was close, but finally a Korean company with a cheaper (and less powerful solution) won. At that time, it was 2004, motherboards were huge comparing to this tiny piece of hardware and I had to deal with different voltage, power consumption, heat dissipation, safety, etc…. so I’m really in love with this tiny piece hardware that doesn’t need even a ventilator or a big dissipation mechanism.

Carles Mateo

Blog on extreme IT, Development, Clouds, SRE, Operations, Start ups, Security, CTO and my thoughts