Gina's Observatory Roll-Off-Roof Automation

[Dr_Ju_ju]

Do you actually need all those LED's, especially if you will be remotely controlling the system.....

[Gina]

They are simply to provide built-in local checking if there's a problem.  Agreed that if everything is working properly they serve little purpose.

[Gina]

4 core screened cable connected to limit switches.

[Gina]

Another update to the circuit diagram showing the motor driver connections.

Edited September 9, 2019 by Gina

[Gina]

Wiring up of the control box nearly complete.

[Gina]

Internal wiring of the control box is complete.

[Gina]

Limit switches re-installed with the new screened 4 core cable.

[Gina]

On closing the roof after last night's imaging run one of the chain joining links came undone a bit and jammed in the large pulley housing.  Unjammed it with brute force (because I needed the roof closed).  Just ordered a couple of links (one replacement and one spare).  I think I shall have to design and print a new large pulley wheel cover with more clearance.

[Dr_Ju_ju]

These things are sent to try us...…   but better to find out now before bad weather sets in & you want to close it quickly.

[Gina]

Took the observatory apart again - well, some of it and took out large pulley with fixing bolt and cover.  Now have it indoors ready to design and print a new cover.  Stuffed a lump of polystyrene packaging in the gap the keep the rain out until I get the new parts installed.

[Gina]

The motor control system is pretty much complete so the firmware is next.  The Arduino sketch is simple - just a loop watching for the various data input conditions.  The RPi firmware will be a modified Astroberry Board INDI driver.  The GUI panel shown in Ekos will have 3 buttons for Open, Close and Stop.  Lights associated with the Open and Close buttons will indicate the progress of the movement - off, moving, finished and fault represented by colours - grey, yellow, green and red.  The Stop button light would normally be grey (off) and green for Stopped.

[Gina]

These are the Arduino inputs :-

1. OPEN - Push button
2. CLOSE - Push button
3. STOP - Push button
4. Rain Sensor (relay)
5. OPEN limit switch
6. CLOSED limit switch
7. RPi Open
8. RPi Close
9. RPi Stop
10. Motor current

I think I should include a timer too, to turn off the motor if the appropriate limit switch is not activated in a reasonable time.  This would also signal a Fault to the RPi, same as the motor drawing too much current.  The cause could be a broken drive chain or connection.

Edited September 26, 2019 by Gina

[Rusted]

Let me see if I have this right: 
Your Arduino has gone all GUI for an Astroberry Ekos?
And now it's stuck onboard at the traffic lights somewhere in the Andi.
R.P.i.

[Gina]

Printing the new large pulley cover.   Here are screenshots of the CAD model and the arrangement for printing in Slic3r.  The Cad model shows the true orientation in use.

[Gina]

Left the print running overnight but this morning found the print had failed near the top! 

[Gina]

Now using a different design with a two part cover so that I can print it flat rather than on edge.  Printed the front which went fine and now the back.

[Gina]

Eventually printed the back after tweaking my printer but found I'd printed the front wrongly - used mirror instead of rotate 180° so came out back-to-front - DOH!!

[Gina]

Tried all sorts to get white PLA to print properly but no joy.  Changed to blue and printing fine!!  Go figure.  3D printers are as much black magic as computers!!

Edited September 28, 2019 by Gina

[Rusted]

12 hours ago, Gina said:

Tried all sorts to get white PLA to print properly but no joy.  Changed to blue and printing fine!!  Go figure.  3D printers are as much black magic as computers!!

I think you mean blue magic.

[Gina]

The print of the front in blue PLA came out fine - virtually perfect.  A gap in the rain enabled me to get out to the observatory and try the new cover parts.  They fit perfectly

[Gina]

Another fine spell has enabled me to connect the drive chain parts with a new link, thread it through the gap between large pulley and casing, through the motor unit, round the small pulley and hook up onto the spring and tension adjuster.  Then tighten the tensioner eyebolt.  Chain drive now ready for using the motor - chain runs very smoothly.  So next job is the programming then I can install all the parts in the box and attach it to the wall.

[Gina]

Here are screenshots of the CAD models of the back and front of the large pulley cover.  About half the cover is outside the observatory when the roof is closed.  The photo shows the old green cover - I have yet to photo the new one.

 

[Gina]

A couple of photos of the outside part of the large pulley cover.

[Rusted]

A thing of beauty is a joy for ever!

[Gina]

Here is a first go at the Arduino sketch.  There are a few refinements to add but I think this is the bulk of it.  I want to add a timeout to turn the power off if the roof takes too long to open or close.   I think the main loop should take only milliseconds in which case I could add in a delay of 0.1 secs and then count in tenths of a second which would be quite adequate for checking timeout.

I've kept the code modular for clarity and ease of diagnosis if it doesn't work as expected.

// Filename :- ROR_Control_2019-11-20
//
bool roofOpen = false; 
bool roofOpening = false; 
bool roofClosing = false;
bool timerRunning = false;
//
int Threshold = 400;     // 2v analog to digital threshold - 1023 = 5v
int currentLimit = 115;  // Motor current sense output gives 140mv per Amp  4A = 140x1024x4/5000 = 115 (100 corresponds to 3.5A)
int timoutCount = 180;   //  Timout in seconds - amount of time alloweed to open or close roof

int pbClosePin = 3;  // Close Push Button
int pbStopPin = 4;   // Stop Push Button
int pbOpenPin = 5;   // Open Push Button
int detRainPin = 6;  // Rain detector
//
int MotorInAPin = 7;  // Motor In A
int MotorInBPin = 8;  // Motor In B
//
int MotorCSPin = A2;  // Motor Current Sense
//
int rpiClosePin = A3; // Remote Close
int rpiStopPin = A4;  // Remote Stop
int rpiOpenPin = A5;  // Remote Open
//
int limClosedPin = A6; // Closed Limit Switch
int limOpenPin = A7;   // Open Limit Switch
//
int rpiFaultPin = 13;  // Remote Fault Sense
//
//
void setup() {
  pinMode(pbClosePin,INPUT_PULLUP);   //  Close Push Button
  pinMode(pbStopPin,INPUT_PULLUP);    //  Stop Push Button
  pinMode(pbOpenPin,INPUT_PULLUP);    //  Open Push Button
  pinMode(detRainPin,INPUT_PULLUP);   //  Rain detector
//  
  pinMode(MotorInAPin, OUTPUT);
  pinMode(MotorInBPin, OUTPUT);
  pinMode(rpiFaultPin, OUTPUT);
 }
//
//
void OpenRoof() {
  MotorInAPin = HIGH;
  
  }
//
void CloseRoof() {
  MotorInBPin = HIGH;
  }
//  
void StopMotor() {
  MotorInAPin = LOW;
  MotorInBPin = LOW;

  }
//
void LimitReached() {
  StopMotor;
  }
//
void MotorStalled() {
  StopMotor;
  rpiFaultPin = HIGH;
  }
//
//
// Test all buttons, inputs and rain detector for change
//
void loop(){
  if (digitalRead(pbOpenPin) == LOW) { OpenRoof; };
  if (digitalRead(pbClosePin) == LOW) { CloseRoof; };
  if (digitalRead(pbStopPin) == LOW) { StopMotor; };
  if (digitalRead(detRainPin) == LOW) { CloseRoof; };
//  
  if ((analogRead(rpiOpenPin) > Threshold)) { OpenRoof; };
  if ((analogRead(rpiClosePin) > Threshold)) { CloseRoof; };
  if ((analogRead(rpiStopPin) > Threshold)) { StopMotor; };
//
  if ((analogRead(limClosedPin) > Threshold)) { LimitReached; };
  if ((analogRead(limOpenPin) > Threshold)) { LimitReached; };
  
//
  if ((analogRead(MotorCSPin) > currentLimit)) { MotorStalled; };
}
// End

Edited November 20, 2019 by Gina