Adding a digital amperemeter to your lasercutter

DISCLAIMER: ONLY CONTINUE READING WHEN YOU KNOW YOUR WAY AROUND HIGH VOLTAGE!!! EVERYTHING YOU DO TO YOUR LASER IS AT YOUR OWN RISK! Lasercutters are great. Especially since they got relatively cheap (you can buy a “40W” K40 Laser on ebay for sub 400€). Since I am a newly certified laser safety officer in my hospital I felt I need such a machine. However I decided against a K40 and opted for a more powerful, more big “50W” 300x500mm Lasercutter (one of the “China blue” variety – but it is actually green). Long story short I am quite impressed, delivery of the ~100kg palette was really quick (as in faster than the safety-googles). The machine is still quite well tuned, the beam seems to be aligned quite well. All in all the machine is not the death-trap I thought I

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Fail: Adventures in ultrasound anemometers

I want a little weather station for the flat. Something with Temperature, Humidity, Rain amount, and of course Wind speed and direction. Normally you’d use a cup anemometer. There are severals other variants, i.e. one measuring the run-time of an ultrasound wave travelling along a known line in the wind. That’s quite interesting… You can buy these SRF04 ultrasound range finders for less than 5€. I removed the mask-rom µC and connected one of these cheap arduino-clones to the outputs. Der Arduino erzeugt also die 44kHz für die Ultraschallsensoren (für ein paar µs) und wartet dann 100ms bis der Zyklus wieder von vorn beginnt. Die Windgeschwindigkeit ergibt sich dann aus der Differenz der Laufzeit zwischen vor- und rücklaufendem Signal und der Schallgeschwindigkeit (sowie Temperatur etc.). Die Transducer habe ich in 3D-Gedruckten (PETG) Haltern in einer Küchenpapier-Rolle montiert, zusätzlich befindet sich

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(Deutsch) Ein Brief an Herrn Dobrindt…

I wrote a letter to the german ministry of transportation regarding his ‘drone’-opposing regulatory efforts (german only): Sehr geehrter Herr Dobrindt, (falls Sie es tatsächlich selbst lesen…) Ich schreibe Ihnen, da ich es doch sehr befremdlich finde, wie Sie mit dem Thema ‘Drohnen’ umgehen. Die von Ihnen geplante Regulierung bzw. der ‘Drohnenführerschein’ sowie die Registrierung der Drohnen ist nicht nur sinn- bzw. nutzlos sondern auch unnötig: 1.) ‘Drohnen’ (also im Allgemeinen sog. ‘Multicopter’ mit elektronischer Stabilisierung) sind im Sinne der Luftfahrtverordnung Modellflugzeuge, also ordentliche Luftfahrzeuge. Für solche sind die von Ihnen beschriebenen Regelungen bereits präsent, wie z.B. das Verbot des Einfluges in Lufträume um z.B. Flughäfen. 2.) Was bringt Ihnen die Registrierung von ‘Drohnen’? Wenn jemand vor hat (illegalerweise) über einem Flughafen oder Atomkraftwerk zu fliegen, wird er doch sicherlich seine Registrierung deutlich sichtbar an der Drohne anbringen, oder? Im

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DJI Zenmuse H3-3D – repair (Part 1?)

Big Drama… I had a pretty horrible crash with my DJI F550. There was a catastrophic resonance which made the copter unstable and uncotrollable. The Drama was, that my beloved DJI Zenmuse H3-3H Gimbal was underneath, when it crashed on the roof. This is how the gimbal looked… (Thank god, the GoPro was OK) The first problem was a sticking ‘roll’-axis. It was easily fixable. The axis of the roll axis has an easily reachable screw which claps the motor to the axis. The arm squeesed onto the regulator PCB due to the crash. Fixing was as easy as loosening the screw and tightening it again. But, at a close look, I found a defect halleffect sensor on the ‘nick’-motor of my gimbal. Normally this is a death-sentence. Googling A search online yielded that the DJI motors are sold and

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Wouxun KG-818 VHF Teardown

On the Hamradio Friedrichshafen I got myself a Wouxun KG-818 VHF (5W, 136-174.995 MHz). I plan to realize a small APRS transmitter for my car. “The Wouxun…” …whithout batteries. You have to remove the screws on the bottom left and right… …as well as the nut around the antenna connector … …to slide-wedge the whole assembly bottomwards-out. The dials will come off as well as some plastic thingy. Beware of the ribbon! The two modules. On the left the processor/TRX-board, on the right, the LCD/speaker/kexs section with part of the case. And once again the TRX/Chinagirl-module. Unfortunately the PCB is soldered to the RF-connector, which prevented me from further teardown, because I had no soldering iron at hand. Underneath the firmwaresticker it reads “M64X802”. Great!” The TRX works even without its keys/speaker etc attached! Well and that’s about it. I

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