Hi Robert,
This is a brilliant project and well written up - perfect for someone like me who is just starting to learn Arduino coding. I have built a test circuit using UNO+ L293D + NEMA17-PG5, I have the components for the preferred hardware on order but for now I'll play with this combination. That motor is a bit of a monster, it weighs 0.5kg and I will be attaching it to a 3" FeatherTouch R&P which I would prefer not to destroy in the event it tries to drive past a hard stop, so I will need to machine a slip-clutch mechanism.
Anyway, my point for this post... I'm mainly an engineer/astrophotographer and from a practical point of view I can see where some mods would be valuable (to me at least). The first is backlash compensation, and the second is the ability to remember the focuser postion between power up cycles (my camera gear doesn't move between sessions so it would be good if the position setting could be recalled). At the moment I'm not competent to make such mods to the code although I do have code snippets that would work if I could shoe-horn them in somehow ;-)
Again, many thanks for your work here Robert!
ChrisH
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Hi Chris
It already remembers a lot of the focuser settings including focuser position, maxsteps etc - see the pdf
re clutch, thats why warnings in the PDF are large font!
Actually there are a number of ways to do this, but each has its limitations. I am in favour of mechanical stop switches but they are difficult to mount. I would prefer a home position switch that is integrated into the focuser HOME (goes to 0) and that way you always have it set right.
I have a 2.5" focuser R&P which is why I gave so much detail on how to do the initial setup with the associated warnings.
As for Backlash compensation, its a bad idea putting it in the arduino code. Its not consistent enough, varies from user to user, and is really best handled by the client. And any changes would need modifying the code (I can overcome that part though)
The client should be able to measure backlash in either direction, a lot of the existing apps have this built in, then you get the conflict of having backlash in the app and in the hardware. Can cause headaches. Its easy enough to do in the arduino but I have avoided this as well as temperature compensation because I believe its best handled in the client app. Being in the client means it can be measured at any time and adjustments made on the fly. Backlash changes over time due to a lot of things, changes in voltage supply, wear and tear, cold/hot all sorts of things. Having it embedded in the arduino means having to recompile and download new versions all the time (I know I could add this and make it user settable etc like I have done for other settings).
I have been playing with myLogViewPro and believe I can do a number of things on the fly (like auto refocusing via temperature compensation) whilst imaging, but thats another story......
R
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Thanks for the reply! I'm going to be using this remotely via ASCOM and SGPro, and so far I have it working fine (on the bench) - in that I have control over focuser movements. Each time I disconnect/reconnect to the focuser though it resets to whatever the starting position I have selected... not what the last focuser position was. I'll go through the PDF again to see what I'm missing ;-)
My other focuser (SharpSky) has a backlash compensation parameter which can be set in the ASCOM driver, maybe I'm getting confused about where such a parameter should go. SGPro I though used a 'there and back' system where it's supposed to overshoot and wind back to the desired position so it approaches it in one direction only. Ilve just been watching the motor closely and that does not appear to be happening at the moment.
I won't be using the push buttons as I operate this scope entirely from a warm room 15meters away, I'd rather have a mechanical slip-clutch which I know will work in an emergency rather than rely on a microswitch which could fail, but I admit it would be a useful feature to have. I'd have no trouble fitting them.
I have the temperature probe working but I use SGPro to trigger an autofocus run on temperature change rather than use compensation (which I never had much success with in the past). Re-focusing every 1degC change seems to work fine.
I'm not going to try and optimise performance of the motor at this time - not until the new driver board turns up in the post. However, trying to get the maximum speed out of this motor is not intuitive! I have used a speed setting of '10' and get a 20,000 step movment in 325sec, if I change the setting to '12' it takes 346sec...
Chris
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There is a 10s before details are saved. So if you issue a move or set position command, it will only save the new value 10s after the command has finished - this prevents burning out the onboard EEPROM.
As for speed, probably over 90% of all movements would be at a slow speed as focusing is best done at slow speed. High speed moves really are not necessary once it is set up and permanent.
In my setup (permanent pier) the change in focus between nights is less than 100 steps.
Speed is relative in that the settings given are an example or guide. Users are free to adjust the setting values to whatever works for them. What is critical with the DRV8825 is to make sure the vref pot is set correctly. Once it is, then the values which determine the speed settings can be altered.
I looked at using torque clutches from RC, I think they might be called slip-clutches, they have them on the transmission of RC (racing cars like Tamiya?), and they do work well. Saves machining as they are also the right size. And fairly low cost too.
Problem with all of this is so many features and variations. I am pretty confident that the myFocuser already has far more user settings and features than most of the professional ones that cost an arm and a leg. Having owned a few of those professional ones that cost 300+ USD I am fairly certain that is the case. I really dont see much more being added in the interim, except of course the wifi controller which looks very promising. We already have Bluetooth which works well, IR and RE options also. And TFT/LCD. Probably too many options, but most of this was "see if I can do" or "that might be cool to do that" just to push the envelope a little.
Cheers
Robert
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Yes as I said, this is a superb project which allows anyone to make their own autofocuser!
I can see that the speed parameter gets saved to EEPROM, and is recalled on next connection. However the position is not (on my setup). I can connect (to the ASCOM driver), rack the focuser out 500 steps, wait 30sec and disconnect. Upon reconnection the position is back to the default (which I have set at 10,000 steps).
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Yes, update is checked on the ASCOM dialog.
OK, I've generated a logfile (I think!). What I did this time was first fire up the Windows app, connect to the focuser, move the focuser 500 steps (or so...), wait 60sec, disconnect. Reconnect shows the position has been remebered.
Next I connect to the ASCOM driver via SGPro, the setting has been reset to default (10,000), I move the focuser 500 steps again, wait 60 sec, disconnect, reconnect, the setting is back to default.
If I connect to the ASCOM driver, move the focuser 500 steps, wait 60sec, disconnect, open the Windows app, then the position has been remembered.
So the ASCOM driver is writing the setting to EEPROM, but when it starts it is not reading it and resetting back to default.
The TFT version can no longer be supported. Sorry, but I cannot fit all the code into the space of a nano, v219 for the TFT is the last of the Mohicans
Last edit: brownrb 2016-03-01
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I have uploaded some of the latest work on the WiFi, such the PDF, the Printed Circuit Boards, some code, etc. I am going to settle on the ESP-07 module purchased with an adapter plate and external antenna. This is currently working.
Other ESP modules such as the ESP-01 and NodeMCU-Lua modules can also be used and they get attached to an adapter plate which plugs into the main ESP8266 sub-board. The ESP8266 sub-board then attaches to the myfocuserpro2 controller.
The PDF shows all of this. We are now in Beta so that means there are still some minor bugs to work out. Thus firmware and applications are subject to change, though I will try to avoid posting any more updates till things are sorted out. I have tested the ESP-07 with the latest Windows App, and the arduino firmware Focuserv220_WIFI_F.ino which seems to work well. The other .ino files I have yet to try but they have been ported from the Focuserv220_WIFI_F.ino code so should also work. There is stil some work to be done on the PDF over the coming weeks and I get time to test some more options.
I have some minor checks left for the code that runs on the ESP8266 module, and will post that soon. The video will be done later today.
and found some issues with the BT options (have ended up rewriting the BT code as part of the wifi) and I will port that revised code to the existing BT based firmware later on
Cheers
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Just wanted to pass on my thanks Robert and report I have a fully functional autofocuser now. It doesn't use the latest version of hardware but the original UNO+293D board, although I have just received some 8825 drivers in the post and I already have a good stock of NANOs to play with. I've tried several motors and settled on a 19:1 NEMA14 as a good balance between power and size, this motor can easily lift my big Moravian G4-16000 + 7-pos filterwheel.
Hi Chris
Glad to hear its working! Congratulations. That is one impressive piece of equipment you have there (or should I say more than one). One look and it says lets image!!
Thanks
Robert
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Major jump forward in the Wifi, have switched to TCP based comms and it is much much faster (connects in about 5s). I pulled out some of my earlier code from a few years back and its up and running
Will start posting some of that later today if I have time
Cheers
Robert
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31-Mar-2016. New Arduino Firmware, New ASCOM drivers, New Windows Apps, New PDF.
Please update. Please read PDF for changes. Please read the pdf in LCD ISSUES folder.
Cheers
Robert
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02 April 2016. Wifi module is released. New Windows App, New Controller Firmware, New ESP firmware. And it works. Only thing left is to update ASCOM driver.
Cheers
Robert
06April2016 - New PDF, added stripboard layout and schematic for users who do not want to make a PCB. New PDF also introduces upcoming new feature: webserver access to wifi focuser - runs at same time as wifi controller, you can access and control the focuser from a webbrowser, wifi app or ascomw driver
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Hi Robert,
One minor point - the temperature resolution is currently set at 0.25deg which probably reflects the probe's overall accuracy but is still a bit low for using temperature compensation (or indeed, using SGPro's auto re-focus mechanism which I do). Mine is currently set to re-focus at 1deg change - and some scopes need to use 0.5deg change as the trigger (Tak 106 for example), so I changed the resolution to 12-bit. The actual temperature is not really relevant, it's the Delta-T (or temperature change over time) that matters... It seems to work OK with this setting but any updates I must remember to repeat the change!
Rgds,
ChrisH
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Hi ChrisH
From memory, the project started out using the default temp resolution of 12 bits. As some stage we started having issues (I cannot precisely recall what) with the temperature and setting it to 10bit resolution fixed it at the time and it was never revisited after that.
It could be fixed by perhaps adding a dropdown menu in the application and sending the resolution that way, and save the resolution setting in the EEPROM.
What version of the arduino focuser firmware are you using, I might mock something up for you to try.
Cheers
Robert
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Hi Robert,
This is a brilliant project and well written up - perfect for someone like me who is just starting to learn Arduino coding. I have built a test circuit using UNO+ L293D + NEMA17-PG5, I have the components for the preferred hardware on order but for now I'll play with this combination. That motor is a bit of a monster, it weighs 0.5kg and I will be attaching it to a 3" FeatherTouch R&P which I would prefer not to destroy in the event it tries to drive past a hard stop, so I will need to machine a slip-clutch mechanism.
Anyway, my point for this post... I'm mainly an engineer/astrophotographer and from a practical point of view I can see where some mods would be valuable (to me at least). The first is backlash compensation, and the second is the ability to remember the focuser postion between power up cycles (my camera gear doesn't move between sessions so it would be good if the position setting could be recalled). At the moment I'm not competent to make such mods to the code although I do have code snippets that would work if I could shoe-horn them in somehow ;-)
Again, many thanks for your work here Robert!
ChrisH
Hi Chris
It already remembers a lot of the focuser settings including focuser position, maxsteps etc - see the pdf
re clutch, thats why warnings in the PDF are large font!
Actually there are a number of ways to do this, but each has its limitations. I am in favour of mechanical stop switches but they are difficult to mount. I would prefer a home position switch that is integrated into the focuser HOME (goes to 0) and that way you always have it set right.
I have a 2.5" focuser R&P which is why I gave so much detail on how to do the initial setup with the associated warnings.
As for Backlash compensation, its a bad idea putting it in the arduino code. Its not consistent enough, varies from user to user, and is really best handled by the client. And any changes would need modifying the code (I can overcome that part though)
The client should be able to measure backlash in either direction, a lot of the existing apps have this built in, then you get the conflict of having backlash in the app and in the hardware. Can cause headaches. Its easy enough to do in the arduino but I have avoided this as well as temperature compensation because I believe its best handled in the client app. Being in the client means it can be measured at any time and adjustments made on the fly. Backlash changes over time due to a lot of things, changes in voltage supply, wear and tear, cold/hot all sorts of things. Having it embedded in the arduino means having to recompile and download new versions all the time (I know I could add this and make it user settable etc like I have done for other settings).
I have been playing with myLogViewPro and believe I can do a number of things on the fly (like auto refocusing via temperature compensation) whilst imaging, but thats another story......
R
Thanks for the reply! I'm going to be using this remotely via ASCOM and SGPro, and so far I have it working fine (on the bench) - in that I have control over focuser movements. Each time I disconnect/reconnect to the focuser though it resets to whatever the starting position I have selected... not what the last focuser position was. I'll go through the PDF again to see what I'm missing ;-)
My other focuser (SharpSky) has a backlash compensation parameter which can be set in the ASCOM driver, maybe I'm getting confused about where such a parameter should go. SGPro I though used a 'there and back' system where it's supposed to overshoot and wind back to the desired position so it approaches it in one direction only. Ilve just been watching the motor closely and that does not appear to be happening at the moment.
I won't be using the push buttons as I operate this scope entirely from a warm room 15meters away, I'd rather have a mechanical slip-clutch which I know will work in an emergency rather than rely on a microswitch which could fail, but I admit it would be a useful feature to have. I'd have no trouble fitting them.
I have the temperature probe working but I use SGPro to trigger an autofocus run on temperature change rather than use compensation (which I never had much success with in the past). Re-focusing every 1degC change seems to work fine.
I'm not going to try and optimise performance of the motor at this time - not until the new driver board turns up in the post. However, trying to get the maximum speed out of this motor is not intuitive! I have used a speed setting of '10' and get a 20,000 step movment in 325sec, if I change the setting to '12' it takes 346sec...
Chris
There is a 10s before details are saved. So if you issue a move or set position command, it will only save the new value 10s after the command has finished - this prevents burning out the onboard EEPROM.
As for speed, probably over 90% of all movements would be at a slow speed as focusing is best done at slow speed. High speed moves really are not necessary once it is set up and permanent.
In my setup (permanent pier) the change in focus between nights is less than 100 steps.
Speed is relative in that the settings given are an example or guide. Users are free to adjust the setting values to whatever works for them. What is critical with the DRV8825 is to make sure the vref pot is set correctly. Once it is, then the values which determine the speed settings can be altered.
I looked at using torque clutches from RC, I think they might be called slip-clutches, they have them on the transmission of RC (racing cars like Tamiya?), and they do work well. Saves machining as they are also the right size. And fairly low cost too.
Problem with all of this is so many features and variations. I am pretty confident that the myFocuser already has far more user settings and features than most of the professional ones that cost an arm and a leg. Having owned a few of those professional ones that cost 300+ USD I am fairly certain that is the case. I really dont see much more being added in the interim, except of course the wifi controller which looks very promising. We already have Bluetooth which works well, IR and RE options also. And TFT/LCD. Probably too many options, but most of this was "see if I can do" or "that might be cool to do that" just to push the envelope a little.
Cheers
Robert
http://www.ebay.com/itm/Traxxas-SLASH-Stampede-4x4-Complete-Slipper-Clutch-TRA6878-/351658139923?hash=item51e0756113:g:oOgAAOSw-zxWn6oZ
http://www.ebay.com/itm/TRAXXAS-SLASH-4X4-Slipper-Clutch-Spur-gear-/201531919919?hash=item2eec3d0e2f:m:mjAK0rKdXvsmaRjkdTMwRag
http://www.ebay.com/itm/NEW-TRAXXAS-REVO-3-3-Slipper-Clutch-Spur-RR34-/131714552073?hash=item1eaacc9109:g:gN8AAOSwu-BWQqKw
Yes as I said, this is a superb project which allows anyone to make their own autofocuser!
I can see that the speed parameter gets saved to EEPROM, and is recalled on next connection. However the position is not (on my setup). I can connect (to the ASCOM driver), rack the focuser out 500 steps, wait 30sec and disconnect. Upon reconnection the position is back to the default (which I have set at 10,000 steps).
Do you have the checkbox called Update checked on the ASCOM setup dialog form?
Ive rechecked the code and it still looks fine. Please generate a tracelog file and send it to me please
Yes, update is checked on the ASCOM dialog.
OK, I've generated a logfile (I think!). What I did this time was first fire up the Windows app, connect to the focuser, move the focuser 500 steps (or so...), wait 60sec, disconnect. Reconnect shows the position has been remebered.
Next I connect to the ASCOM driver via SGPro, the setting has been reset to default (10,000), I move the focuser 500 steps again, wait 60 sec, disconnect, reconnect, the setting is back to default.
If I connect to the ASCOM driver, move the focuser 500 steps, wait 60sec, disconnect, open the Windows app, then the position has been remembered.
So the ASCOM driver is writing the setting to EEPROM, but when it starts it is not reading it and resetting back to default.
Last edit: Chris Heapy 2016-03-01
If Update is checked, then it first sends whatever the value is in Max Position and Focuser Position to the controller when connecting.
If you want to retrieve the last position used by the focuser when connecting, then Update must be Un-Checked.
Please try it with Update turned off and let me know what happens. The logfile seems fine.
Ah, you're right - with update off then it recalls the last focus position setting! Sorry about that, all good now ;-)
The TFT version can no longer be supported. Sorry, but I cannot fit all the code into the space of a nano, v219 for the TFT is the last of the Mohicans
Last edit: brownrb 2016-03-01
Hoping to post a video later today of a working myFocuser2Wifi controller
I have uploaded some of the latest work on the WiFi, such the PDF, the Printed Circuit Boards, some code, etc. I am going to settle on the ESP-07 module purchased with an adapter plate and external antenna. This is currently working.
Other ESP modules such as the ESP-01 and NodeMCU-Lua modules can also be used and they get attached to an adapter plate which plugs into the main ESP8266 sub-board. The ESP8266 sub-board then attaches to the myfocuserpro2 controller.
The PDF shows all of this. We are now in Beta so that means there are still some minor bugs to work out. Thus firmware and applications are subject to change, though I will try to avoid posting any more updates till things are sorted out. I have tested the ESP-07 with the latest Windows App, and the arduino firmware Focuserv220_WIFI_F.ino which seems to work well. The other .ino files I have yet to try but they have been ported from the Focuserv220_WIFI_F.ino code so should also work. There is stil some work to be done on the PDF over the coming weeks and I get time to test some more options.
I have some minor checks left for the code that runs on the ESP8266 module, and will post that soon. The video will be done later today.
Last edit: brownrb 2016-03-15
Video will be up in about an hour (its still loading to (youtube)
https://youtu.be/nDaWtiJTo2M
and found some issues with the BT options (have ended up rewriting the BT code as part of the wifi) and I will port that revised code to the existing BT based firmware later on
Cheers
Just wanted to pass on my thanks Robert and report I have a fully functional autofocuser now. It doesn't use the latest version of hardware but the original UNO+293D board, although I have just received some 8825 drivers in the post and I already have a good stock of NANOs to play with. I've tried several motors and settled on a 19:1 NEMA14 as a good balance between power and size, this motor can easily lift my big Moravian G4-16000 + 7-pos filterwheel.
Some images in this PhotoBucket album, I used a 3D printer to make a small box to hold the electronics etc. http://s970.photobucket.com/user/ChrisLX200/library/Astro%20-%20ODK12
Cheers,
Chris
Hi Chris
Glad to hear its working! Congratulations. That is one impressive piece of equipment you have there (or should I say more than one). One look and it says lets image!!
Thanks
Robert
Major jump forward in the Wifi, have switched to TCP based comms and it is much much faster (connects in about 5s). I pulled out some of my earlier code from a few years back and its up and running
Will start posting some of that later today if I have time
Cheers
Robert
31-Mar-2016. New Arduino Firmware, New ASCOM drivers, New Windows Apps, New PDF.
Please update. Please read PDF for changes. Please read the pdf in LCD ISSUES folder.
Cheers
Robert
02 April 2016. Wifi module is released. New Windows App, New Controller Firmware, New ESP firmware. And it works. Only thing left is to update ASCOM driver.
Cheers
Robert
04April2016 New Wifi PDF and new Wifi ASCOMW driver for Wifi. That completes Wifi for the time being.
Cheers
Robert
06April2016 - New PDF, added stripboard layout and schematic for users who do not want to make a PCB. New PDF also introduces upcoming new feature: webserver access to wifi focuser - runs at same time as wifi controller, you can access and control the focuser from a webbrowser, wifi app or ascomw driver
Hi Robert,
One minor point - the temperature resolution is currently set at 0.25deg which probably reflects the probe's overall accuracy but is still a bit low for using temperature compensation (or indeed, using SGPro's auto re-focus mechanism which I do). Mine is currently set to re-focus at 1deg change - and some scopes need to use 0.5deg change as the trigger (Tak 106 for example), so I changed the resolution to 12-bit. The actual temperature is not really relevant, it's the Delta-T (or temperature change over time) that matters... It seems to work OK with this setting but any updates I must remember to repeat the change!
Rgds,
ChrisH
Email me and I'll send you the latest version to try
Hi ChrisH
From memory, the project started out using the default temp resolution of 12 bits. As some stage we started having issues (I cannot precisely recall what) with the temperature and setting it to 10bit resolution fixed it at the time and it was never revisited after that.
It could be fixed by perhaps adding a dropdown menu in the application and sending the resolution that way, and save the resolution setting in the EEPROM.
What version of the arduino focuser firmware are you using, I might mock something up for you to try.
Cheers
Robert