Category Archives: Tech

Analog Meters to display CPU and memory load

While this is a old project from 2019, I decided to make a more responsive one, after my friend Tyrone mentioned a project somewhere on the internet (forgot where).
Time to dust off this project!

2019 version

Above version worked but was slow.
I used a python script to send values to de controller.

Memory setup was the same.

Below my new schematic, using an opamp to drive the analog meter.

Untested design .. Yeah I got bored on new year’s eve

Utilizing a MCP41000 digital potmeter and a LM358 signal amplifier I hope to get a more responsive setup.

Input to display MQTT and maybe Serial.

Old version

Made a JavaScript plugin for Hydra

Control your effects using MQTT.

You can add anything to control your effects using RotaryEncoders, sensors and other data values.

I’m fixing the code to make use of free MQTT servers on the internet.
Then I’ll post the JavaScript in the Hydra forum or discord.


Calling the JavaScript in https://hydra.ojack.xyz/ website

https://gist.githubusercontent.com/fashice/2098d1301117b86caed94aca8f2101ff/raw/7d2a7300e7ddf42d4f1793f693dbb517e09bd2d8/gistfile1.txt
change mqtt server and add to hydra using
await loadScript("https://domain/script.js¨);

Working on a (C64) handheld probe oscilloscope

These will be available in my shop.

Probably a webpage with measured examples are usefull.

There is a cover for the pogo pin which holds the ground clamp

Handheld device to measure voltages and make screenshots using an application.

Control over serial

  • Select USB device to connect
  • Start a capture to screen
  • Clear (redraw probe screen)
  • Rotate screen for left/right-handed people and easy reading
  • Sample time speed in microseconds
  • 5V reading but 15 volt tolerant, due to the SID pins
  • ??? love to hear ideas

I’m currently working on streaming output.

Below, an example of screenshotting.

Below, measuring outputs from a NE555 (dutch comments)

WHY2025

In case of doubt .. MORE LEDS!

We went to WHY2025 a hackers camp in the Netherlands.

The first time I went was in 1997, with Bigred.
Many followed after that.
Tyrone, Bigred were also there from our old Crew.
Coline joined me several times since 2005.

I joined the Badge team, and was making spacers for the Badges in bulk using my 3D printer.
Also made some fancy cases.

In case of doubt .. more leds!

Nice weather, good friends. New friends. Booze. Food and Hacking.
We visited a lot of talks and enjoyed the music. (And fire)

I worked on: RSS feed on a epaper display, Midi monitor and the MQTT Pong website.

RSS Feed display

While waiting in line for the Badge:

A stone was passed from behind!
It was a ping request. We passed it forward, and 15 minutes later a TTL time exceeded stone came from the front of the line.
You gotta love those nerds!

The Badge:
This should have got much potential ..
Many misses, much to learn.

Sadly broken:

Our 7M Led string attached to Bigred’s Antenna.

Busy .. work and play

While working on my clients projects, I’ve been busy with other Fun stuff.

All will be posted more about soon

  • Designing 3D models for printing
  • Testing Arduino Code for RS485!
  • Creating T-shirt prints using 3D printing and bleach/paint with Vincent !
  • Transforming my Lab
  • Testing UM25C logging possibilities
  • Testing queries on overpass-turbo.eu (So much fun)
  • Playing chiptune music using Synthcart + Midi
  • Made V2 displayer on my 64×64 HUB75 led display
  • Bought a directional Wi-Fi antenna, tweaking wireshark to pinpoint rogue access points and clients.

Animatronics Tentacle Test

Using 3x SG90s (metal gears).
These performed far better using my Servo tester than the cheap plastic ones.

First version using Openscad, with variables to control how it looks.

This is printed using TPU.

RepeatingBit = 4;
nr = 20;
difference(){
union(){
for (a =[0:nr]) {
    translate([0,0,(a * (RepeatingBit))]) {
        translate([0,0,a*a*1.3])
        
        cylinder ( h=1+(a*1.1), r1=1,r2=7.5+(a*(a/10)), $fn=30 );
        translate([0,0,a*a*1.3+1+(a*1.1)])
        cylinder ( h=3+(a*1.5), r1=7.5+(a*(a/10)),r2=7.5+(a*(a/10)), $fn=30 );
        
        }
}
translate([0,0,0])
cylinder( h=650, r1=2,r2=4 , $fn=30 );
}

translate([5,0,-10])
rotate([0,2.5,0])
cylinder( h=1000, r1=1,r2=1 , $fn=30 );
translate([-3,4,-10])
rotate([-4/2,-3/2,0])
cylinder( h=1000, r1=1,r2=1 , $fn=30 );
translate([-3,-4,-10])
rotate([4/2,-3/2,0])
cylinder( h=1000, r1=1,r2=1 , $fn=30 );

translate([2,3,-10])
rotate([-1.4,0.6,0])
cylinder( h=1000, r1=2,r2=nr*1.3 , $fn=30 );

translate([2,-3,-10])
rotate([1.6,0.7,0])
cylinder( h=1000, r1=2,r2=nr*1.3 , $fn=30 );

translate([-3.5,0,-10])
rotate([0,-1.8,0])
cylinder( h=1000, r1=2,r2=nr*1.3 , $fn=30 );

}

Video with some organic movement

Using a Raspberry Pi, Python3 and a Servo HAT.

Bottom part

Some tests with SDR (Software Defined Radio)

I’ve got a little SDR stick a while ago with some antenna’s.

I’ve got some extra antenna’s

So I was playing around with P2000 and Airplane Radio (tracking overhead planes)

Airplane info in terminal
P2000 info
Local webserver on my laptop tracking overhead planes.

For debugging I used SigDigger

dump1090-mutability --aggressive --interactive --net --net-http-port 8080 --net-sbs-port 30003 

git clone https://github.com/Zanoroy/multimon-ng.git
 cd multimon-ng/
 mkdir build
 cd build
 cmake ..
 make
rtl_fm -f 169.65M -M fm -s 22050 -p 83 -g 30 | ./multimon-ng -a FLEX -t raw /dev/stdin

dump1090-fa --interactive

Music Cover Art Display using ILI9341

Little Sunday afternoon project.

Two PHP scripts.

Install on your webserver (see previous post)

Resizes images and removes the onkyo header.
(See previous posts)

<?php
// onkyo.php
// write jpeg header
header('Content-type: image/jpg');

$lines = file_get_contents('http://IP-ONKYO-AMPLIFIER/album_art.cgi', false);
$lines = explode("\n", $lines);
// remove weird Onkyo header (3 lines)
$content = implode("\n", array_slice($lines, 3));
print $content;
?>

CoverArt from a squeezeboxserver

<?php    
// squeezebox.php
// leave playerid as is, for the default.
// change to MAC address of player to get coverart specific player
$img = file_get_contents('http://IP-LOGITECH_MEDIA_SERVER:9000/music/current/cover.jpg?player=<playerid>');
$im = imagecreatefromstring($img);
$width = imagesx($im);
$height = imagesy($im);
$newwidth = '240';
$newheight = '240';
$thumb = imagecreatetruecolor($newwidth, $newheight);
imagecopyresized($thumb, $im, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
//imagejpeg($thumb,'small.jpg'); //save image as jpg
header('Content-Type: image/jpeg');
imagejpeg($thumb);
imagedestroy($thumb); 
imagedestroy($im);
?>

Arduino install:

Start IDE
Install TJpg_Decoder library
Open examples>Tjpeg_decoder>SPIFFS>SPIFFS_web_spiffs
change wifi credentials
and the url to your php script.
  bool loaded_ok = getFile("https://myserver/onkyo.php", "/M81.jpg"); // Note name preceded with "/"

replace bottom part with

 // while(1) yield();
 delay(5000);
     SPIFFS.remove("/M81.jpg");