belzebalex

6 ms·

1.
by belzebalex 2y ago
A nice mention about this is the outstanding and quiet work of the Cosys-Lab of the University of Antwerp. They once put a microphone array below a scorpio, and showed how bats moved their ultrasonic beam to scan for a scorpio. Incredible s
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by belzebalex 2y ago
1) and 3) are valid, but 2) isn't really. In that sort of pipeline, you usually do IQ sampling which allows you to phase-shift by any arbitrary value with a complex multiplication.
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by belzebalex 2y ago
The main reason is that it's tough to have a uniform sound pressure distribution on a stage. That means the people at the front usually have very high sound levels, while those at the back have way lower. Technicians then make the trad
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by belzebalex 2y ago
This is quite sad, I've been very inspired by the writings of Artem Litvinovich [1] (although he stopped publishing 8 years ago). I inspired a lot of my research on what he did. https://www.ribbonfarm.com/author/ar
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by belzebalex 2y ago
This is incredible. I've wanted to thank the author for a while for his past articles [1][2] which have been a wonderful source of information when working on my sonar systems [3]. This article again explains really well a complicated
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by belzebalex 3y ago
I tried to use SymPy for a similar problem: computing the Jacobian of a complicated integral using quaternion rotations. Problem was that the symbolic results were way too complicated and the simplify function didn't help much. So, I g
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by belzebalex 3y ago
Role: Six-month intern/fixed term job March-September 2024 Location: Anywhere in the world (on-site), willing to relocate Skills: * Digital signal processing, machine learning, computer vision, control theory, electronic
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by belzebalex 3y ago
One method that solves 99% of your control problems is the Ziegler-Nichols method [1]. It's a shame it's not taught more often. No need to model your system, just increase the P gain until the system oscillates naturally. Measure
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by belzebalex 3y ago
Yes it does, you have to manipulate the expression to make it adimensional. But this rule-of-thumb is only valid for systems whose response time is less than 500ms.
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by belzebalex 3y ago
I'm working on a 3d sonar to replace costly lidars. Already have a state-of-the art prototype that has better performance than $3k lidars for under a hundred bucks. Applications are robots that need to navigate autonomously in a non-co
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by belzebalex 3y ago
Role: Six-month intern/fixed term job March-September 2024 Location: Anywhere in the world (on-site), willing to relocate Skills: * Digital signal processing, machine learning, computer vision, control theory, electronic
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by belzebalex 3y ago
Got my first internship building drone navigation systems after building my own quadcopter flight control board (software included) ( https://github.com/alextousss/quadcopter ) By the way, looking for a second one March-
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by belzebalex 3y ago
Role: Six-month intern/fixed term job March-September 2024 Location: Anywhere in the world (on-site), willing to relocate Skills: * Digital signal processing, machine learning, computer vision, control theory, electronic
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by belzebalex 3y ago
I'm surprised this does not include the excellent Alchitry boards [1] which are quite cheap and capable ($100 for an Artix-7 35T dev board is a steal) [1]: https://www.sparkfun.com/categories/tags/alchitry
15.
by belzebalex 3y ago
Location: USA/out of France Internship Willing to relocate: Yes, from France Technologies: C, C++, Python, Javascript, Django, React, Verilog, Arduino, STM32, ... Résumé/CV: alextoussaint.com/resumev2.pdf Email:
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by belzebalex 3y ago
Location: USA/out of France Internship Willing to relocate: Yes, from France Technologies: C, C++, Python, Javascript, Django, React, Verilog, Arduino, STM32, ... Résumé/CV: alextoussaint.com/resume.pdf Email: al
17.
by belzebalex 3y ago
Location: USA/out of France Internship Willing to relocate: Yes, from France Technologies: C, C++, Python, Javascript, Django, React, Verilog, Arduino, STM32, ... Résumé/CV: alextoussaint.com/resume.pdf Email: al
18.
by belzebalex 3y ago
Built one of the first 3d ultrasonic scanner that works in the air to make an autonomous drone [1] [2] [1]: https://www.alextoussaint.com/2021-04-28_How-I-built-an-ultr... [2]: https://hackaday.com/2021&#x2F
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by belzebalex 4y ago
Location: USA/out of France Internship Willing to relocate: Yes, from France Technologies: C, C++, Python, Javascript, Django, React, VHDL, Arduino, STM32, ... Résumé/CV: alextoussaint.com/resume.pdf Email: alex@
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by belzebalex 4y ago
How did it end?
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by belzebalex 5y ago
I think your analysis is great, but a better solution might be to just pay and consider teachers better. Here's a data point: in France, after high school, we're put for two years into a "preparatory class" where we prep
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by belzebalex 5y ago
Was badly stressed preparing for the entrance exam for engineering schools. It was to the point I had heart palpitations for hours. Two things made it disappear: - Sport, even just running an hour a week stopped the palpitations - Magnesiu
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by belzebalex 5y ago
You're completely right. I think the second order effects are negligible at this scale.
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by belzebalex 5y ago
Not at all! There are many "Ecole Normale" which are just schools for teachers. The "Superieure" refers to the fact that you have to pass a hard exam to get in. And once there you can do research or become a teacher in a
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by belzebalex 5y ago
Author here, the title is a bit misleading. In the article, I specify that it's the first 3d ultrasonic scanner (of my knowledge) that works in the air .
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by belzebalex 5y ago
I'm in France ;-)
27.
by belzebalex 5y ago
Would you have any links please? I didn't see any that did small development batches for a price lower than 200 EUR.
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by belzebalex 5y ago
I definitely would like an English translation. Though, from what I understand (the diagram and the translation of the title) it's a graphic input device that can work out a few points at the time, and not in the same sphere (as echos
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by belzebalex 5y ago
It is exactly what it is, except I used ultrasounds (40khz, easy to work with) instead of electromagnetic waves.
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by belzebalex 5y ago
That's smart. Didn't think about it! Though, the emitter is pulsed and I also rely on the fact that it stops resonating after I cut out the power. Unless my LC oscillator has a low Q, it will keep oscillating after I cut out the s

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