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Sep

2021

How to fix PlatformIO Olimex E407 LED_BUILTIN not working

Problem

You are trying to run a firmware on the Olimex E407 that blinks the builtin green status LED. You code uses LED_BUILTIN similar to this:

#include <Arduino.h>

void setup() {
    pinMode(LED_BUILTIN, OUTPUT);
}

void loop() {
    digitalWrite(LED_BUILTIN, LOW);
    delay(500);
    digitalWrite(LED_BUILTIN, HIGH);
    delay(500);
}

but when you upload the code onto the board, the LED does not blink and stays off.

Solution

Instead of LED_BUILTIN, use PC13 – the pin the LED is connected to (which you can see on the Olimex E407 schematic:

#include <Arduino.h>

void setup() {
    pinMode(PC13, OUTPUT);
}

void loop() {
    digitalWrite(PC13, LOW);
    delay(500);
    digitalWrite(PC13, HIGH);
    delay(500);
}

Sep

2021

How to fix PlatformIO STM32 Error: libusb_open() failed with LIBUSB_ERROR_ACCESS

Problem:

While trying to program your STM32 board using stlink and PlatformIO (most programmers integrated onto a development board are STLink programmers), you see this error message:

xPack OpenOCD, x86_64 Open On-Chip Debugger 0.11.0-00155-ge392e485e (2021-03-15-16:43)
Licensed under GNU GPL v2
For bug reports, read
        http://openocd.org/doc/doxygen/bugs.html
debug_level: 1

hla_swd
Error: libusb_open() failed with LIBUSB_ERROR_ACCESS
Error: open failed
in procedure 'program'
** OpenOCD init failed **
shutdown command invoked

Solution:

You need to setup the correct permissions for the STLink usb devices – in other words, install the correct stlink udev rules files. On Ubuntu, install stlink-tools using

sudo apt -y install stlink-tools
sudo systemctl restart udev

After that, unplug your stlink (or development board) for 5 seconds and plugin it in again. This will cause the new device permissions to take effect.

Now you can retry uploading the firmware from PlatformIO.

Sep

2021

How to start KiCAD installed from flatpak

After you have installed KiCAD from Flatpak using

flatpak install --from https://flathub.org/repo/appstream/org.kicad.KiCad.flatpakref

you can run it using

flatpak run org.kicad.KiCad

You can append any arguments to KiCAD, for example open a project file directly from the command line:

flatpak run org.kicad.KiCad MyProject.pro

Sep

2021

How to fix KiCAD Unable to add inotify watch: (error 28: No space left on device) on Linux

Problem:

When opening KiCAD on Linux, you see the error message Unable to add inotify watch: (error 28: No space left on device):

Solution:

You need to increase the number of inotify watches that can be active at once:

echo fs.inotify.max_user_watches=65536 | sudo tee -a /etc/sysctl.conf && sudo sysctl -p

and then restart KiCAD

Sep

2021

How to create pandas pd.DataFrame from list of dicts

You can create a pandas pd.DataFrame from a list of dicts (lst) using the pd.DataFrame(lst) constructor.

a = {"x": 1, "y": 2}
b = {"x": 3, "y": 2}
c = {"x": 6, "y": 9}
df = pd.DataFrame([a,b,c])

df will look like this:

Sep

2021

How to fix git credential manager core: git fatal: No credential backing store has been selected.

Problem:

After installing git credential manager core, you see this error message:

fatal: No credential backing store has been selected.

Set the GCM_CREDENTIAL_STORE environment variable or the credential.credentialStore Git configuration setting to one of the following options:

  secretservice : freedesktop.org Secret Service (requires graphical interface)
  gpg           : GNU `pass` compatible credential storage (requires GPG and `pass`)
  cache         : Git's in-memory credential cache
  plaintext     : store credentials in plain-text files (UNSECURE)

See https://aka.ms/gcmcore-linuxcredstores for more information.

Solution:

If you are on a graphical computer, run

git config --global credential.credentialStore secretservice

On a server, if automated i.e. passwordless access is required, use

git config --global credential.credentialStore plaintext

Note that this is insecure since all the passwords are stored in a plaintext file.

Sep

2021

How to install git credential manager core on Ubuntu 22.04 / 20.04

This will install git credential manager core on Ubuntu 22.04 or Ubuntu 20.04

wget "https://github.com/git-ecosystem/git-credential-manager/releases/download/v2.4.1/gcm-linux_amd64.2.4.1.deb" -O /tmp/gcmcore.deb
sudo dpkg -i /tmp/gcmcore.deb
git-credential-manager configure

Sep

2021

How to identify the latest npm package version

You can use

npm info [package name] version | head -n1

to print just the latest package version, for example:

npm info @angular/cli version | head -n1

The head -n1 part is neccessary to suppress unwanted npm info messages. Just running the command without head -n1 :

npm info @angular/cli version

prints the following output:

12.2.6
npm notice 
npm notice New minor version of npm available! 7.21.1 -> 7.24.0
npm notice Changelog: https://github.com/npm/cli/releases/tag/v7.24.0
npm notice Run npm install -g [email protected] to update!
npm notice

I typically use the node:latest docker container instead of a local npm to find the latest version of an npm package:

docker run -it --rm node:latest npm info meshcommander version | head -n1

At the time of writing this article, the command prints

0.9.0-d

Sep

2021

How to run one-off command in docker

If you want to just run a command on a docker image without permanently creating a container, run

docker run -it --rm [image] [command]

for example

docker run -it --rm node:latest npm --version

By using --rm we tell docker to immediately remove the container once the command has finished.

Sep

2021

How to optimize MySQL/MariaDB tables in docker-compose

If your MariaDB / MySQL root password is stored in .env , use this command:

source .env && docker-compose exec mariadb mysqlcheck -uroot -p$MARIADB_ROOT_PASSWORD --auto-repair --optimize --all-databases

You can also directly use the root password in the command:

docker-compose exec mariadb mysqlcheck -uroot -phoox8AiFahuniPaivatoh2iexighee --auto-repair --optimize --all-databases

Sep

2021

How to rotate Raspberry Pi LCD by 180°

In order to rotate a DSI-connected LCD screen like the Raspberry Pi 7″ LCD screen by 180 degrees, append

lcd_rotate=2

to /boot/config.txt

Sep

2021

How to unpause Marlin after M0/M1 echo:busy: paused for user

In Marlin, you can pause the firmware using M0 or M1 which will cause the firmware to loop-print

echo:busy: paused for user
echo:busy: paused for user
echo:busy: paused for user
echo:busy: paused for user
echo:busy: paused for user
echo:busy: paused for user

In order to continue or unpause, use

M108

Sep

2021

How to reboot Marlin using G-Code

On most Marlin boards, you can use M997 to reboot/restart the microcontroller:

M997

While this is technically the command to update the firmware, on most boards this is implemented by a simple reboot, which will load the bootloader which could update the firmware e.g. if there is a firmware.bin file on the SD card. Since unless a firmware update is intended there is no such file on the SD card, the M997 command will just reboot the board.

Sep

2021

How to disable StealthChop in Marlin using Trinamic TMC2xxx/TMC5xxx

In Marlin, you can disable StealthChop using M569 S0 <axes>. Typically, you want to store the settings to EEPROM using M500 after running M569.

This will set the X Y Z mode to SpreadCycle instead of StealthChop:

M569 S0 X Y Z
M500

Sep

2021

How to get size of compressed file using JSZip

In JSZip, you can get the file size of a file compressed inside a ZIP archive by first decompressing it using zip.file(...).async(...) into an ArrayBuffer and then using .byteLength to get the size of the buffer.

zip.file("filename.txt").async("ArrayBuffer").then(function(data) {
    var fileSize = data.byteLength;
    // TODO Your code goes here
})

Full example

This is based on our post on How to uncompress file inside ZIP archive using HTML5 & JSZip which reads a local file using a HTML5 file input. This example prints the file size of every file inside the ZIP archive:

<html>
<body>
    <input type="file" id="myfile" onchange="onMyfileChange(this)" />

    <script src="https://unpkg.com/[email protected]/dist/jszip.js" type="text/javascript"></script>
    <script type="text/javascript">
        function onMyfileChange(fileInput) {
            if(fileInput.files[0] == undefined) {
                return ;
            }

            var filename = fileInput.files[0].name;
            var reader = new FileReader();
            reader.onload = function(ev) {
                JSZip.loadAsync(ev.target.result).then(function(zip) {
                    zip.file("word/document.xml").async("ArrayBuffer").then(function(data) {
                        console.log("word/document.xml is", data.byteLength, "bytes long");
                    })
                }).catch(function(err) {
                    console.error("Failed to open", filename, " as ZIP file:", err);
                })
            };
            reader.onerror = function(err) {
                console.error("Failed to read file", err);
            }
            reader.readAsArrayBuffer(fileInput.files[0]);
        }
    </script>
</body>
</html>

Example output

word/document.xml is 88369 bytes long

Sep

2021

How to list files inside a ZIP archive using JSZip

In JSZip, you can list files inside a ZIP archive using zip.fileswhich is an Object with key = filename and value = file metadata object.

JSZip.loadAsync(fileContent).then(function(zip) {
    for(let [filename, file] of Object.entries(zip.files)) {
        // TODO Your code goes here
        console.log(filename);
    }
}).catch(function(err) {
    console.error("Failed to open", filename, " as ZIP file:", err);
})

Full example

This is based on our post on How to read local ZIP in HTML5/Javascript using JSZip

<html>
<body>
    <input type="file" id="myfile" onchange="onMyfileChange(this)" />

    <script src="https://unpkg.com/[email protected]/dist/jszip.js" type="text/javascript"></script>
    <script type="text/javascript">
        function onMyfileChange(fileInput) {
            if(fileInput.files[0] == undefined) {
                return ;
            }

            var filename = fileInput.files[0].name;
            // var filesize = fileInput.files[0].size;
            var reader = new FileReader();
            reader.onload = function(ev) {
                JSZip.loadAsync(ev.target.result).then(function(zip) {
                    console.log(zip)
                }).catch(function(err) {
                    console.error("Failed to open", filename, " as ZIP file");
                })
            };
            reader.onerror = function(err) {
                console.error("Failed to read file", err);
            }
            reader.readAsArrayBuffer(fileInput.files[0]);
        }
    </script>
</body>
</html>

Sep

2021

How to read a file inside a ZIP archive as string using JSZip

Want to read as an ArrayBuffer instead? Read How to read a file inside a ZIP archive as ArrayBuffer using JSZip

In JSZip, you can read a compressed file as JavaScript string using

zip.file("filename.txt").async("string").then(function(data) {
    // data is a string
    // TODO your code goes here, this is just an example
    console.log(data);
})

Full example

This is based on our post on How to uncompress file inside ZIP archive using HTML5 & JSZip which reads a local file using a HTML5 file input. You can upload any .docx file for testing:

<html>
<body>
    <input type="file" id="myfile" onchange="onMyfileChange(this)" />

    <script src="https://unpkg.com/[email protected]/dist/jszip.js" type="text/javascript"></script>
    <script type="text/javascript">
        function onMyfileChange(fileInput) {
            if(fileInput.files[0] == undefined) {
                return ;
            }

            var filename = fileInput.files[0].name;
            var reader = new FileReader();
            reader.onload = function(ev) {
                JSZip.loadAsync(ev.target.result).then(function(zip) {
                    zip.file("word/document.xml").async("string").then(function(data) {
                        // data is a string
                        // TODO Your code goes here!
                        console.log(data)
                    })
                }).catch(function(err) {
                    console.error("Failed to open", filename, " as ZIP file:", err);
                })
            };
            reader.onerror = function(err) {
                console.error("Failed to read file", err);
            }
            reader.readAsArrayBuffer(fileInput.files[0]);
        }
    </script>
</body>
</html>

Sep

2021

How to read a file inside a ZIP archive as ArrayBuffer using JSZip

Want to read as a string instead? Read How to read a file inside a ZIP archive as string using JSZip

In JSZip, you can read a compressed file as ArrayBuffer using

zip.file("filename.txt").async("ArrayBuffer").then(function(data) {
    // data is an ArrayBuffer
    // TODO your code goes here
})

Full example

This is based on our post on How to uncompress file inside ZIP archive using HTML5 & JSZip which reads a local file using a HTML5 file input:

<html>
<body>
    <input type="file" id="myfile" onchange="onMyfileChange(this)" />

    <script src="https://unpkg.com/[email protected]/dist/jszip.js" type="text/javascript"></script>
    <script type="text/javascript">
        function onMyfileChange(fileInput) {
            if(fileInput.files[0] == undefined) {
                return ;
            }

            var filename = fileInput.files[0].name;
            var reader = new FileReader();
            reader.onload = function(ev) {
                JSZip.loadAsync(ev.target.result).then(function(zip) {
                    zip.file("word/document.xml").async("ArrayBuffer").then(function(data) {
                        // data is an ArrayBuffer
                        // TODO Your code goes here!
                    })
                }).catch(function(err) {
                    console.error("Failed to open", filename, " as ZIP file:", err);
                })
            };
            reader.onerror = function(err) {
                console.error("Failed to read file", err);
            }
            reader.readAsArrayBuffer(fileInput.files[0]);
        }
    </script>
</body>
</html>

Sep

2021

How to get size of ArrayBuffer in Javascript

You can get the size of an ArrayBuffer in Javascript using .byteLength:

var buf = new ArrayBuffer(8);
buf.byteLength // == 8

Sep

2021

How to uncompress file inside ZIP archive using HTML5 & JSZip

In our previous post How to read local ZIP in HTML5/Javascript using JSZip we provided an example of how to use JSZip to list files inside a local ZIP archive using HTML5.

This post will expand upon this in order to read the content of a file compressed inside a local ZIP archive file.

In this example, we’ll read a local ZIP file using HTML5 <input type="file"> and uncompress its content. We’ll read the word/document.xml file, so you can upload any .docx file to test that.

JSZip.loadAsync(ev.target.result).then(function(zip) {
    zip.file("word/document.xml").async("ArrayBuffer").then(function(data) {
        // data is an ArrayBuffer
        // TODO Your code goes here!
    })
}).catch(function(err) {
    console.error("Failed to open", filename, " as ZIP file:", err);
})

Full example

<html>
<body>
    <input type="file" id="myfile" onchange="onMyfileChange(this)" />

    <script src="https://unpkg.com/[email protected]/dist/jszip.js" type="text/javascript"></script>
    <script type="text/javascript">
        function onMyfileChange(fileInput) {
            if(fileInput.files[0] == undefined) {
                return ;
            }

            var filename = fileInput.files[0].name;
            var reader = new FileReader();
            reader.onload = function(ev) {
                JSZip.loadAsync(ev.target.result).then(function(zip) {
                    zip.file("word/document.xml").async("ArrayBuffer").then(function(data) {
                        // data is an ArrayBuffer
                        // TODO Your code goes here!
                    })
                }).catch(function(err) {
                    console.error("Failed to open", filename, " as ZIP file:", err);
                })
            };
            reader.onerror = function(err) {
                console.error("Failed to read file", err);
            }
            reader.readAsArrayBuffer(fileInput.files[0]);
        }
    </script>
</body>
</html>

How to fix PlatformIO Olimex E407 LED_BUILTIN not working

Problem

Solution

How to fix PlatformIO STM32 Error: libusb_open() failed with LIBUSB_ERROR_ACCESS

Problem:

Solution:

How to start KiCAD installed from flatpak

How to fix KiCAD Unable to add inotify watch: (error 28: No space left on device) on Linux

Problem:

Solution:

How to create pandas pd.DataFrame from list of dicts

How to fix git credential manager core: git fatal: No credential backing store has been selected.

Problem:

Solution:

How to install git credential manager core on Ubuntu 22.04 / 20.04

How to identify the latest npm package version

How to run one-off command in docker

How to optimize MySQL/MariaDB tables in docker-compose

How to rotate Raspberry Pi LCD by 180°

How to unpause Marlin after M0/M1 echo:busy: paused for user

How to reboot Marlin using G-Code

How to disable StealthChop in Marlin using Trinamic TMC2xxx/TMC5xxx

How to get size of compressed file using JSZip

Full example

Example output

How to list files inside a ZIP archive using JSZip

Full example

How to read a file inside a ZIP archive as string using JSZip

Full example

How to read a file inside a ZIP archive as ArrayBuffer using JSZip

Full example

How to get size of ArrayBuffer in Javascript

How to uncompress file inside ZIP archive using HTML5 & JSZip

Full example

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