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remipch

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Articulated Robotics: building a ROS2 mobile robot

articulatedrobotics.xyz
3 points·by remipch·पिछला वर्ष·1 comments

Show HN: Homemade automated solar concentrator

github.com
296 points·by remipch·2 वर्ष पहले·87 comments

comments

remipch
·4 माह पहले·discuss
On the subject of higher dimension mathematics, I recently discovered this video : "The most beautiful formula not enough people understand"

You might find it interesting too.

https://www.youtube.com/watch?v=fsLh-NYhOoU
remipch
·4 माह पहले·discuss
There is "MESSAGE IN A BOTTLE.txt".

The first game here is to understand what the code does without a high-level README.
remipch
·4 माह पहले·discuss
Thank you for sharing, I'm just starting to dig into Lua language and Love2D game engine.

I will explore your game source too.
remipch
·पिछला वर्ष·discuss
Hi Michael,

[0] is a thread reproducing what I described. In that case I would like Phind's last answer to provide me with a link to the documentation or source code of 'NormalizedLandmarkList'.

I hope you find it useful.

[0] https://www.phind.com/search/cm77vnj8e0000206g4mgp66br
remipch
·पिछला वर्ष·discuss
Unfortunately, I don't remember them anymore and I regularly clear my browser cache.

Maybe it's just the case you're describing but I'm pretty sure I was really looking for appropriate sources and they weren't provided.

If you want, I can send you my queries if I see this again.
remipch
·पिछला वर्ष·discuss
As an occasional user, what I really liked in your previous version was that Phind always gave the list of sources.

So my workflow was :

- ask a question

- quickly read the given answer

- go to the main sources to decide if they are trustworthy or not

I noticed that the new version does not always give the sources, even when I ask. Is this intentional or do you plan to revert this in the near future ?

It also solves the problem of not reducing the traffic to the content creators you use.

Anyway, congratulations for making this tool and offering a free plan to test it.
remipch
·पिछला वर्ष·discuss
Hi HN!

I just discovered Josh Newans' projects and tutorials about mobile robotics on ROS2.

I find them particularly clear and straightforward, and I think some HN people here might find them interesting as well.

It can be great for beginners to explore the project, but as a robotics engineer myself, I also find some specific topics really useful and well explained. The ROS2 documentation is not always as clear as it could be.

Hope you enjoy!
remipch
·2 वर्ष पहले·discuss
I don't know if it has its place here but for a minimalist static website, here is my approach:

- create a simple html template using simple.css [0]

- write markdown files

- wrap pandoc [1] in a simple bash script to manually convert markdown to html

- and that's it.

By minimalist, I mean: no script, no component, no database, no react, no SEO.

The result is a minimalist website that you write in markdown.

It's very limited compared to full-featured frameworks, but it can do the job for a simple website.

Here is mine: [2] (I'm not a web developer at all).

[0] https://github.com/kevquirk/simple.css

[1] https://pandoc.org/

[2] https://remipch.github.io/
remipch
·2 वर्ष पहले·discuss
What do you mean by "better"? There are several aspects to consider.

Indeed the advantage of your photovoltaic solution is versatility in the face of clouds and lower mechanical costs.

But the drawback is the larger panel area, higher panel cost and probably shorter panel lifetime.

Photovoltaic efficiency is about 20%, while even low-cost mirrors reflect 90% of the energy.

It really depends on the specific application and the answer does not seem so obvious to me.
remipch
·2 वर्ष पहले·discuss
> not sure where you are based in France

I answered your question too quickly, I'm near Clermont-Ferrand, we have several local brewery here.
remipch
·2 वर्ष पहले·discuss
> Taking a computer out of the loop is the best way to guarantee speed and reliability.

As suggested by pjc50 in another comment [0], a passive safety would be good for this application.

The main drawback being the space required to protect the entire danger zone.

> Bon travail et bonne chance!

Merci beaucoup

[0] https://news.ycombinator.com/item?id=41390704
remipch
·2 वर्ष पहले·discuss
Thanks for your kind and detailed reply.

> it occurs to me that your system only requires an occasional movement rather than a rapid movement for tracking purposes

Right, actually the system wakes up every 10 seconds to check if the angle needs to be adjusted. It often does not and waits for the next 10 seconds.

There is an opportunity to implement true "hibernation" while the system is waiting to save some more power, but it's not done yet.

> Secondly, the motion system appears to be single-ended and based upon a rope and a stepper motor. It would perhaps be useful to consider conversion to a more rigid system.

Actually there are two geared motors, allowing to control both angles.

Yes, I use simple ropes, the system is stable enough thanks to the counterweight (all ropes are always under tension, making the whole system stable).

> In short, if you have knowledge of your own geometry, have known orientation relative that fixed point, and can before activation determine the TOF distance to your target, and have a GPS fix thus solar inclination at that moment is calculable, then it should be possible to track the target without the need for visual feedback.

My project takes the opposite approach: using a low-cost camera board to avoid having to measure all the geometric aspects precisely.

> In terms of temperature sensing, you can obtain remote temperatures using infra-red linear systems which should be effective.

Good idea, I haven't implemented temperature sensing yet, but I'll look into infrared sensors.

> In terms of safety, laser TOF ensuring no change in distance would ensure the subject is still within the programmed range and an intermediate object hasn't been introduced for combustion.

It may be too late, the intermediate object/person is already heating up by the time we detect it.

> In terms of gathering interest, not sure where you are based in France but I could suggest structuring the system as a public sculpture and holding events including eating food cooked by the system which could involve the additional sponsorship of local wineries, cider, etc. to garner social support.

Yes I'm in France, it would be nice to present the system at such events. For the moment I'd much rather get to work on the technical side.

> Smiles from Sydney. I applaud your work toward the application of technology to social and environmental concern, we need more of this.

Thank you
remipch
·2 वर्ष पहले·discuss
Yes I've seen a solar dish warmer with a satellite dish (manually adjusted).

It was clever.
remipch
·2 वर्ष पहले·discuss
With the low-cost camera used here, the small red/green/blue pattern would be indistinguishable because the whole spot is saturated.

It might be possible with an expensive camera.
remipch
·2 वर्ष पहले·discuss
Yes, this is exactly how I planned to control the temperature : add a temperature sensor in the oven and implement a simple PID in the supervisor to do so.
remipch
·2 वर्ष पहले·discuss
Nice interactive visualizations !

Yes, it might be complicated to build.
remipch
·2 वर्ष पहले·discuss
FYI, this is the "vacuum adjustable focus mirror" I mentioned:

https://lm.solar/order/4-square-rigid-aluminum-composite-mir...
remipch
·2 वर्ष पहले·discuss
Nice explanation, thanks
remipch
·2 वर्ष पहले·discuss
Excellent!

Do you know the mirror area used here?
remipch
·2 वर्ष पहले·discuss
Oh yes, they do. I can be a little naive sometimes :-)

I still naively think that we could make mirrors completely encased in glass to limit their degradation (pure speculation here).