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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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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New videos!

First of all, here the promised hot air video: Then, I made a video (little boring I admit it) about milling alu on my CNC. I made this video because the setup produced a very nice suface finish… Music by Markus Menz

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Playing with lasers

I remembered to have a old HeNe laser tube laying around which I got for some bucks some years ago … at the Ham Radio fleamarket. I don’t own a neon transformer so it was pretty much laying ’round without any use. I rediscovered it today and I decided to hook it up to my 15kV (AC) high tension transformer. I used a 1k470 series resistor to keep “power down”. Pics… (klick for high res!)

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Update

No action here lately… so that’s a quick update… 1) UsbProg My favourite allround-programmer… I am still developing (selfless- and restlessly) my reflow oven (5 freely programmable phases and 130 profiles storagable on the oven itself… coming soon). Howsoever I put my reflow-controller PCB on a USB-stick with some metal casing… Which did not kill my reflow controller but the UsbProg instead… The mega32 used on the UsbProg must have been completely fried; the bootloader flashed some LED helplessly but my PC didn’t recognize the USB-device anymore. I was unable to flash the IC using my STK500 so … with other words… destroyed. So I ordered a new UsbProg and I exchanged the damaged M32 on the old one, which was a success, it works great again! Here are some pictures of the “birth” of my second UsbProg (click for

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