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[GigiG]

Hi, just completed and it works fine. At the bottom of my web page, a couple of images and the design lauyot made with Inkscape.
Cheers

[jmaurin]

GigiG, why are you using proto-shield now, since you have designed a board just for this? I'm just asking because I was thinking of build your board.

[GigiG]

Hi jmaurin, I built a proto-shield version because a friend of mine doesn't have the capability to etch a PCB by himself so I decided to design and verify the feasibility of an AstroEQ on a prototype board. I tought it can be an alternative option for anyone that want to avoid the PCB etching.

[PhilCrompton]

Your proto-shield one looks a lot neater than mine. I think you have done this before .

Phil

[GigiG]

In fact I started the board design about two months ago and the refinement was almost maniacal  . To be honest, the idea was to design a board suitable for both AstroEQ and OnStep ... and I'd say that's probably true. Not tested completed with OnStep yet because I haven't been able to get communicate the ASCOM server with the board (same hardware, works just fine with AstroEQ  )

[Phill]

Hi GigiG,

It's great to see someone else here from PICgoto.

I've finally decided it's time to retire the old board and carry on with AstroEQ and Arduino. Thanks for the proto-board images on your site. They will save me a whole load of time and probably a few costly mistakes, 

To everyone else, Hello! and especially to Tom, many thanks for the great project and the enormous amount of work you have  done.

[GigiG]

I've finally decided it's time to retire the old board and carry on with AstroEQ and Arduino. Thanks for the proto-board images on your site. They will save me a whole load of time and probably a few costly mistakes, 

Hi Phill, did you start making the board? I'm glad to hear that my pictures may help. Please keep me informed on your progress

[Phill]

Hi GigiG,

I hope you are well.

I have, "sort of", made a start. I am still waiting for the proto-board. It's on a slow boat from China! Everything else I have. So far the only set back I have had is that I cannot solder the wire I bought.  , I'll visit the local electronics shop on Saturday and see if I can get some decent 4 core.

My wife is going back to the UK next Thursday, so I have some painting to do, mix and pour the concrete for my pier, and build the proto-board if it arrives. Thanks to your site it all seems straight forward. Famous last words.

I'll post some images once there is something substantial.

Phill

[Phill]

Hi GigiG,

My proto-shield arrived today so I should be able to get on with it soon. I noticed on your site that you used a step down converter to generate 10 volts for the arduino. What was your thinking there? Are you using a higher voltage for your motors, or is the arduino really not happy with 12 volts at vin?

On the mount side the hole is dug, steel is ready, and the top plate is fabricated. Just waiting for my local builder's merchant to deliver the former, sand, gravel and cement.



Phill

[GigiG]

Hi Phill, I use 12V for my steppers, I only wanted to keep the possibility to power the board (steppers) with more then 12V (e.g. in order to increase their slew speed as already tested on the PicGoto++). The Arduino is happy with 7.5-12V input voltage, no problem

[Phill]

Hi GigiG, thanks for the reply. I'm using my old ATX power supply to give 12v, 5v and 3.3v. I do it that way as from what I have read the clone Mega is not always as robust as it could be. It would make sense to drop the 12v to 10v just to feed it.

I've made a start on the proto-board. Redundant headers removed, motor capacitors added, and thinking about using an ESP wifi board once everything is up and running.



An unexpected bonus was the board already having a power and stat LED, bottom left.

[Phill]

The finished proto-shield mounted on the Mega2560.



The new capacitors arrived this morning and have been mounted. No short circuit. I aslo changed out four capacitors on a radio board and it is working too. You would think I was a happy bunny but no. Neither of the two 8825 modules can have their currents limited. It's a choice of zero or 0.9 volts for the vref. Getting your money back is fine, but doesn't compensate for the delay. My advice, if you want a trouble free build, either buy it from Tom or pay the extra and get your parts from a reputable supplier.

Looking on the bright side the pier is finished, just needs a few more days before I hang the scope on it. I might even get the "lawn" tidied up before she who must be obeyed returns from her shopping trip to the UK,



Good luck!

[Phill]

Just as information for those who may come across a similar problem. The two "faulty" DRV8825 break out boards were from Banggood. I received a credit for them but was able to keep the boards. Having a few minutes this afternoon it looks like it's a fairly simple fault. On both boards the vref  10K pot is ~ 7K and has only one very small part of the track that works. Hence zero output over most of it's range and about 1.5K in the tiny spot that does work.

I'll pull them off later and see if I can replace them with working ones. I'm sure I've got a strip somewhere but the damn things are so small that when I do finally dig them out they will probably be the wrong size/value. 

EDIT: No chance they were 1K but I do have some 8.2K and 1.5K fixed value which at least would test the theory but is going to make my board look a bit "dead bug"!

[Phill]

AstroEQ built on an Arduino Mega 2560 and a FADI_MEGA368P proto-board.



Tracking speed is correct and with my current motors, capable of X80 slew and 0.45 arcsec/step.

I have some better motors on order which I hope will get the slew rate up.

[Phill]

Just to re-iterate what I said before. The proto-shield route is a fairly simple way to get a working AstroEQ. However it is prone to a lot of annoying little faults.

My RA lead from the plug to the board was a little long which gave me an intermittent fault only when the lid was on! 

All sorted now, and running on 0.9 deg/step nema 17s without problems, at X300.

Thanks again Tom.