Gina

CO seems to show there's a chance of clear dark sky tonight but OTOH it also says 11% cloud ATM whereas my view of the sky says more like 90% cloud. I guess time will tell. Meanwhile, it looks like rain!

Just hoping I feel better tomorrow - haven't been feeling 100% today. Going to have an early night.

With the inaccuracy of the ROR, I'm having a re-think on the limit switches. I think I shall arrange levers to be operated by the roof that then operate limit switches.

I agree about transparency. I too am imaging Cygnus but much wider view including NAN, Sadr Region and Cygnus Loop with 55mm f1.8 lens NB filters and ASI 1600MM-Cool camera. The Crescent is pretty small in my images.

Heavy showers all day - I expect you've had the same.

ATM tomorrow night looks promising but we all know how quickly things can change.

Connecting the RPi means additional pins used on the Arduino for both input and output. This may mean using some of the Analog pins as Digital I/O. Motor current can have 3 states - none, normal operation and excessive and thus needs 2 pins. With the 3 control lines from RPi to Arduino this means the RPi will use 5 separate pins on the Arduino. I think the Nano with its extra Analog pins compared with the Uno may have sufficient I/O altogether but if not I can always use a Mega (I have several no longer used, from 3D printers). Since the RPi uses 3.3v logic and the Arduino 5v I shall have to convert the Arduino outputs to 3.3v logic to avoid destroying the RPi. Opto-couplers are probably the best option for signals both ways to protect the ultra-sensitive RPi.

This application does not need a fast response from the logic and polling of the inputs will be quite adequate - interrupt mode is not needed though I might use interrupt for ABORT depending on how the coding goes. I shall not be using the dedicated Arduino library for this motor driver but write my own code. When I get to using the RPi for remote control I plan to return codes that show what is happening. Three buttons will be provided on the user interface - OPEN, CLOSE and ABORT. ABORT will almost instantly cut power to the motor. The OPEN and CLOSE buttons will have an associated light to show the motor state and current, viz:- Off (Grey) indicates motor off Green - motor running and drawing current within normal range Amber - motor current excessive, indicating something preventing normal roof motion Red - may be used to indicate an error condition such as no motor current I may use another light to indicate rain detected.

Each half of the dual motor driver has 5 connections plus a common Vdd and Gnd. EN/DIAG - ENable or Diagnostics - logic 1 to enable motor INA - connect the A motor output to Gnd or Vin INB - connect the B motor output to Gnd or Vin PWM - Speed control - logic 1 for full speed (connect to Vdd) CS - Current Sense - Output giving the motor current - 140mv per Amp In the list above lines 1. and 4. can be connected to Vdd (logic 1) and lines 2. and 3. used to control the motor as shown in the truth table above. Both logic 0 for OFF/STOP and one or other logic 1 to run the motor clockwise or anticlockwise. From the above just two lines are needed to control the motor. ie. 2 digital output pins on the Arduino. Digital inputs required are :- OPEN - Push button CLOSE - Push button ABORT - Push button Rain Sensor (relay) OPEN limit switch CLOSED limit switch RPi Open RPi Close RPi Abort Push buttons and relay need "debounce" logic. An analog input comes from the CS (current sense).

Back to the electronics. I have decided to use an Arduino for the main control but whether this is a Uno or Nano remains an option. I could get some Arduino through feed sockets with pins for the motor shield to use with a Uno or just wire from a Nano to the edge connections on the motor shield. I think the latter probably wins overall.

Forgot to take a photo - I'll do it tomorrow if it's fine (looks like it won't be). While discussing the window, I still need a bracket or something to pull the window open until its own weight takes over. ATM it stays in the upright (closed) position if released. It would be rather helpful if opening the roof pulled the window open (or pushed it) but an offset weight seems to be the standard way.

Life would be much more difficult or expensive! And less interesting 😄

Sun's out again now. Taken some photos of the rainwater downpipes. The specially shaped downpipe from the guttering was 3D printed to get the right amount of offset. First two photos are with the roof closed and the third with it open so that I could get far enough back from the downpipe.

It's stopped again but there's thunderstorms forecast throughout the night!

Sorry, photos will have to wait - it's raining. Got the rainwater downpipes sorted out just right!

Just finished replacing the downpipe arrangement to take water off the ROR and directed into the next field, away from the observatory. Photos to follow...

Little chance of any imaging in the next week or so but I'm slowly working on my ROR motor drive and other improvements to the observatory.

3D printed pulley block with ball bearing printed, assembled and installed in the observatory. This one works faultlessly 😀 I'll take and post a photo or two later.

Other options are Hall effect switch and magnet or opto sensor - I have both in stock. I think I would prefer the latter for better positional accuracy. I think for extra failsafe, I'll detect the motor current and stop if this exceeds a set value, indicating an obstruction on the roof or limit switch failure and roof at end of travel. This is easily arranged in the Arduino sketch.

No, I don't have a thingiverse account. I'm afraid I don't speak your language - could you please post in English on here.

I see.

What would you suggest for mechanical devices, bearing in mind the possibly damp conditions?

Interesting. If I have any problems with WiFi, I'll seriously consider this. I did have a run of CAT6 UV resistant cable running to my observatory but with a Ubiquiti AP I find WiFi quite adequate.

Possibly.

Designed and now printing a new pulley block with ball bearing sheave.