perfrej

I use the FTDI chip in my designs and the problem with com port numbering in Windows is only an issue if you unplug the device, and then replug it while the application still has the old com port open. It then gets the next available number - a process that actually makes sense. If you unplug again and make sure that the application doesn't have the port open it will revert to the original number. That's FTDI 231XS. Do't know about the other ones.

/p

I went for the ready-made VM... Works great. I am currently adding Qt's development environment in order to at least get a half-decent environment for actually programming. Spoiled by Visual Studio 2015, I am (whatever you think about windows, VS2015 is the most advanced environment out there).

/per

2 hours ago, Gina said:

I use the serial numbers to identify my Atik cameras in the software.

They would still have the same GUID in ASCOM and be indistinguishable... Only the direct driver way works, for instance with serial number, but if you load an ASCOM driver and want two instances theyu need to have different GUIDs, so two versions of the driver are needed.

11 hours ago, ajk said:

One thing does pop out at me though. They sell a second DC Focuser with an alternative PID code and separate driver install so people can use two focusers at the same time.

That is so that they can use two instances of an ASCOM driver. ASCOM does have the slight disadvantage of only permitting one device per GUID, but on the other hand, if you had two focusers with the same data in the hardware description, how would you keep track of which focuser is which? You really need to give them separate IDs some way.

/per

19 hours ago, Gina said:

Using an RPi at my pierhear/scope/multi-imaging rig would be great IMO.  Could be fine for DSO imaging but too slow for planetary that will need USB3.  Should be fine for all sky cam too.  Pi 3 has wifi I gather   In which case the ASC would require just a 12v power cable only

Oh, don't ever venture down the dark WiFi path! It inevitably leads to utter despair! Cable it...

/per

I confirm that I will spend some time with INDI, most likely in July or August, and produce a driver for 10Micron products and the Remote Control USB Hub. Being a remote buff, Ekos scheduler is the thing that finally got my attention, and I will most likely contribute at least logic input, if not code, to that project.

Luckily, I do not do guided imaging at all, so one less component to worry about. I am interested in novel ways of focusing the telescope, but I have not yet researched how that is done in the Ekos environment.

At this time, my vision is to use a Pi 2 or 3 in a Losmandy extension unit between mount and scope, and to run an INDI device server in that. The rest of the logic (Ekos) can execute either in that thing or in a separate and more powerful computer elsewhere. All I need is one 12V feed and one Ethernet up to the mount. Perhaps I can have this running in my remote observatory in Provence by Christmas or so. I plan to go down in late November and should have something ready and balcony tested by then.

Whoah!

/per

Well, you need maybe 10 commands to do everything you want to do. Not too much to code

/per

I am a bit unsure as to what you mean. Are you talking about a client to the LX200 protocol, or an implementatin of the protocol itself? The latter would be for controlling dedicated hardware, the former for talking to hardware that talks LX200.

Maybe a peek at INDI?

/per

Downloaded... Looks OK. Will test at Olly's tonight, weather permitting.

I just wish people would stop using red for apps and computers. For anyone wiht astigmatism it is a nightmare, and for me, red ruins my dark adaption completely. I prefer dim with normal colours...

/per

Well, both Corpze and I know what sensor is in those things (hint: it is a dollar or two) so this is a prime target for DIY. Corpze built one, and I have built one, but the software published needs som polishing as the processor takes a total hike if you try to measure in daylight. Eventually I will put a permanent one in the obsy, Olly, and then the readings will be readily available (and logged) for us all. Maybe I should speed this project up now that you have a "real one" to calibrate against...

/per

Jeez! Will you ever be done with this? I guess it is like sailing; it is not the destination but the travel itself

/per

Well, there really isn't much to say about this as it is just about as perfect as it can get. I really, really like the rendition and colour!

Hats off to you both!

/per

You're getting there! You don't really need soft start when you run the motor off of 12V supply. But then again, it is cool to fiddle the acceleration software!

/per

Haha! Well, our flap rests nicely horizontally on three stands. Now why would you need to fold all the way down? Another type of flap to use would be the one that Peter Shah uses on his roll-off. It is a wonderful design!

/per

This was my conceptual of it and Olly just changed some details regarding angles.

Obviously, the roof has not been cut out to make use of the flap in this image...

In real life, this is what it turned out as:

/per

Just let the roof push a lever. I designed one of those approximately and Olly realized with some changes of his. It works very well and is 5m long and 50cm high. Doing it that way eliminates any login in the open and close sequences as well, which is nice.

/per

Excellent! That means parts available

/per

I have the same make of motor.I bought the control unit and motor unit for £50 second hand but unused with no chain or rack.

I removed the motor and limit switches to use with a rack i got laser cut at work and fabricated side wall plates each side. should be finished by sunday .

The model of motor and remote control unit is a duo 650l

Gina's motor is a Marathon 800N from Sommer/Aperto. I guess motor wise it is the bigger brother of your's. There is also the 1100N which we use in Provence.

I just found UK prices for the full units: http://www.sommer.eu/mm/mm004/PL_Preisliste_UK_201103.pdf

From that:

I do not know the drive method of the Duo, but Marathon is straigh, standard bicycle chain which is convenient.

All the best,

Per

OK, first of all, get the breakout. It is the same thing only you have to solder the pins to the Arduino. It is also much cheaper. The software is the same and it is configurable for which pin is connected to what on the breakout. Second, don't use the software supplied as it is a poorly written library. Better to just check what it does and mimic the code in a better way. It is dead simple to write the software for it.

Our motor uses only 1.5A rolling our 4x5m roof that weighs several hundred pounds. Initial current at startup rarely exceeds 4A, and when the snow is on the roof and it moves with varying friction we do not usually exceed 2.5A. In other words, you are looking at reasonably low currents in your setup. In Provence, which is not H-bridge controlled, I measure the current five times a second, and if ten successive readings exceed 4A I stop it. It has never stopped due to this in actual operation, but if you put your shoulder against it while closing it will trip after about two seconds. That way I can take the varying currents, but a fault in the rails or a boar sleeping on the wall will trip it and save the motor. Let's call it "soft fuse".

In order to cope with initial currents without issues I suggest you use a 13.8V power supply and a 12V 20Ah (or more) battery in parallel. That will absorb all current spikes nicely which a 10A supply may not do. This is especially important if you run other stuff off the same supply. It is the principle employed in Provence (a 45 Ah car battery) and it works very nicely. I have a voltage drop at the computer of about 0.3V with roof running, making it 13.3 or so. I run everything off of that supply so I am battery backed and will pack up and close after 5 minutes of power gone (implementing that right now).

Now, back to current consumption... You are used to a winch motor and they are beasts with power to spare. they are also inefficient and may very well use 5A or more just turning the motor. I am running my tests on a windshield wiper motor, which is very similar, albeit a bit more power hungry, to the garage door motor. You will find that using properly balanced motor solutions will keep you well down in terms of current consumption, something that is generally very good.

So, promise me you will never attempt to use a 1.5 HP winch again! (except for towing cars out of ditches)

All the best,

Per

Gina,

You should use a REAL H-bridge for several reasons:

Protected by diodes

Reverse polarity protection with external FET

Thermal shutdown

Protection against accidental ON on both sides

PWM input pin

Logic levels

30A capacity, about 8A continuous without cooling

Low Ron (18 mohm)

Current sense output

Suggested product is the VNH-5019, available from Pololu as either a dual chip Arduino shield or a single chip breakout board:

https://www.pololu.com/product/1451

https://www.pololu.com/product/2507

This is the one I have on the bench right now and it is dynamite!

/per

That looks right, Gina. Just lose all the electronics and drive the motor directly.

/per

Just got it. The largest is SEK 1862 plus tax and freight, the middle one SEK 1215 plus tax and freight. The freight to Olly's last time around was SEK 280 plus tax.

/p

My H-bridge design is coming along nicely and I now have firmware for full motor control and am working on speed sensing. The idea is to make sure that the roof rolls at an even speed regardless of temporary fluctuations in load. I'll implement a PID, I think, to regulate everything.

/per

Waiting for a response from them about price and delivery

I'll check it out tomorrow... But do take the middle one. The motors are 18V and run so nicely and calmly at 12V, albeit with somewhat less torque.

I am currently running H-bridge tests for roof motor control... Looking good!

/per