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Thanks Paul! :)

If anyone would like to experiment with a prototype board, but is put off by the SMD soldering, I can do that bit for them? Or do all the soldering. Let me know.

The A4988 looks good, I hadn't seen that before. The current board is only 74x67mm (3" x 2.5") so I don't know how useful shrinking it down further would be? I have done a new design that fully integrates 2x A3697 (as used on the EasyDrivers) and the power circuit onto a single board, which would be more compact, but that wouldn't save much money as it is already so cheap.

I think a single board controlling multiple heliostats makes sense when it is expensive, but if you can make the controller cheap enough, it makes the wiring a LOT neater to have one controller per heliostat? You also have fewer problems with signal noise over long cable runs. I'm planning to have 5 heliostats in my back yard, with just a single 12V line powering them.

Cheers
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Heliostat Projects / Re: Super low-cost heliostat with ESP8266 for WiFi control
« Last post by Paul L on August 06, 2017, 05:17:56 AM »
That looks great, and I'm excited to see it working!  I'd order a board, but I'm strapped for time and have never done SMD before, so I'll have to pass, but I'm interested in buying a fully finished one when you get to that point!  Keep us updated and keep up the good work! 

Just a thought, and it would require a board redesign, buy if you use A4988 driver boards (I think they're similar to the Easy Driver in specs), you could shrink the size of the board (or put 4 drivers on it and control 2 separate heliostats) quite a bit. 
   
Cheers,

Paul
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I thought some of you might like to see my progress with this project - I've been working on the electronics, and I have my own custom PCB! No need for any Arduino or other board. It takes a single DC input 4.75V-28V, and has an ESP8266 for WiFi control, 2 stepper motor drivers (the red EasyDriver boards), and connections for attaching limit switches:



I have a handful of prototype PCBs without any components on - would anyone like one? I can give you a list of the extra bits you'd need to buy, and you'd obviously need to be able to solder (the smallest components are 0805 SMD). The total cost once you've put it together will be less than 20/20/$20. For all the electronics to control a heliostat! It does work, but remember it is a prototype and I'm making no promises  ;) I haven''t got the software finished yet, but you can program it with any code you like using the Arduino IDE and a USB-to-serial adaptor.

3 in the UK, including P&P
5 for mainland Europe, including P&P
$6 for the rest of the world, including P&P

This is what you'd get - just the bare board, no components and no software:



I am planning a new version of the board that I hope to be able to sell already-soldered so you can just plug it in and go.

Cheers
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Hi,

Yes, that's right :) I'm still working on the code to improve accuracy.  Sorry for the delayed reply, i thought this thread was kind of dea, but I'm happy someone finds this useful.

let me know what kind of details you are interested in, I'll be glad to share anything
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Heliostat Projects / Re: Super low-cost heliostat with ESP8266 for WiFi control
« Last post by moritz on May 29, 2017, 01:01:50 AM »
Hi Nick and Gabriel,

I have that bi-weekly maker / diy radio show called "Netzbasteln" on german national public radio Deutschlandfunk Nova. See netzbasteln.de for all past projects. Quite some of them contained an ESP8266, which i really felt in love with. Same goes for the idea of a heliostat which I wanna build in one of the two next shows - which is already next sunday - or also two weeks later. I am really enthusiastic and grateful for the great work you did here, Gabriel!

For my heliostat I already welded the frame (using a bicycle fork), now its up to the motors (will use steppers and Pololu A4998 / 8825 drivers I already used for a CNC and and an Eggbot) and the code. I want to use an ESP8266 (propably Wemos D1 Mini) and program a small webserver on a hotspot that allows you to control everything in a web-browser. Nick wrote:

I'm sharing all my code with Gabriel as I go along, and I'm hoping that at some point we'll have a single source tree that automatically recognises its hardware, and compiles the correct code for the Uno/Mega/ESP8266.


My question: would you mind me (and two friends who are professional programmers and would help) joining this effort and send me the code you are already working on? Guess it would even be best to put it on github and work on it together there! I can do that if you want.

Some work for ESP8266 has already been done - but i assume its a very old version and we should start over anyway:
http://cerebralmeltdown.com/forum/index.php?topic=854.msg3400#msg3400

Many greetings, really looking forward!
Moritz
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I haven't tried it in awhile, but I was able to install it on my Windows 10 machine and use it without any issue at all. Thanks!
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Thanks for the program Gabriel. Does your software work on the latest Windows 10 and does it still work properly?
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Hi luiklodwig,

I really like this idea because it creates closed loop system, such that accuracy of mechanical parts doesn't play big role.
As I understand, camera is stationary, not moving, pointed towards the target, right?

I plan to build something similar, but instead of camera use light sensor mounted at target window. Because in my case, distance between mirror and target window is only around 2 meters.

I would use time of day for coarse positioning, and once achieved use light sensor for fine adjustments

Can you provide more details of your implementation?
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Heliostat Projects / Re: Worm thoughts
« Last post by Paul L on April 23, 2017, 07:58:57 AM »
Just a quick update on this idea:  It works really well as far as moving power is concerned.  I hooked up a 5v 28byj-48 to a common tuning peg, and attached it all to a lazy susan bearing which would act as the azimuth.  I stacked a three foot tall pile of textbooks on it, and it had no problem moving the whole thing, which was really amazing to me seeing how the running voltage was 5v, and roughly 200mA if I remember correctly (I did this a few months after the original post, so it's been awhile).  I'm guessing the books weighed thirty lbs.  It's slow but it works, and the resolution was pretty darn good!  The only drawback is the play when the motor stops - it's really sloppy.  There would have to be some kind of resistance to pull against the heliostat to tighten everything up.

I did take pictures with all the pieces I used, but I can't seem to find them now....I'll post them if I come across them.

This would most likely be the cheapest way to build a heliostat  - I think the motors, couplings, and tuning pegs came to less than ten dollars - per heliostat!  And it's not just a toy, it can move practical amounts of weight, including, I would guess, full sized mylar mirrors (4'x8').     
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Heliostat Projects / Re: Super low-cost heliostat with ESP8266 for WiFi control
« Last post by Gabriel on April 15, 2017, 10:28:27 AM »
This is a bit of a delayed reply, but you shouldn't need anti-backlash nuts. What would be more helpful is more of a say anti-backlash heliostat. So, the altitude and azimuth motions would be pulled in one direction by say a spring or a weight. That would help eliminate any wobble.

Also, It's something that I don't think I have documented well, but the closer you can keep the mirrors towards the axis of rotation the better. There will always be some drift as they get further and further  away, which may or may not be the reason for Paul's drift.

It's technically something that could be compensated for in the software, but it would add yet one more variable to the settings as I believe that you also need to have the distance to the target programmed in. I haven't gotten around to figuring out the math to compensate for it either.

I don't think it would take much to run a heliostat, or heliostats, off of solar. In the grand scheme of things they don't use much power. All they do is move part of a revolution forward and backward in each axis once a day, which amounts to practically nothing for smallish machines.

I actually managed to pick up a solar kit which even has the outdoor box for the batteries and charge controller for $10 dollars where I work, so I am planning on doing pretty much the same thing. Whenever I finally finish 3D printing all of the parts for it. Only 40 more hours of printing to go. ;)

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