14-07-2015 Arduino Firmware v207 for all FULL versions with temperature probe. Overcomes issue when used with FocusMax. Recommend install new firmware and update to latest ASCOM driver release.
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01082015 - New Updates - new document pdf. New DRV8825 HW203 versions, layout, schematic, firmware files (has nao + drv8825 on same stripboard), new TFT_2.2 files, new windows application, new bluetooth files, docs, firmware, layout, schematic (based on DRV8825-HW203 version)
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28082015 New Windows and Windows Mini applications. Code changes consolidated - a lot of changes under the hood for better reliability and error handling. Remove older versions using control panel prior to installing these latest versions.
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29082015 WindowsASCOMApp tester program critical update.
I am also making changes to the ASCOM drivers and will post the new versions in the next few days.
Note: BWOE
The recent changes have been/are to ensure that conformity exists across all software releases (mydcfocuser, myfocuser, myfocuser2) in the way that exception handling and logging is performed. Early releases left out some of the critical error handling (only a problem if nothing goes wrong) - and so these changes should make it much more resilient and recoverable in the unlikely event of some unexpected exception occurring. Am trying to cover most unlikely scenarios that in the majority of cases users will not experience, but if they do, it will be logged and the application/driver should be able to recover.
Please ensure you upgrade to all the new application/driver releases as they are made available - there is no support for prior releases.
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
30082015 New myFocuser2ASCOM drivers (and ASCOM Conform validation) uploaded.
Update to this release.
Note: in reading temperature, there is sometimes about a 1-2s delay as the controller performs the calculation. If an application repeatedly calls GetTemp then this can slow down the controller. Hence, when a GetTemp request is issued, if the focuser is moving then the last known reading is returned. If the focuser is not moving, then a timestamp is used such that a minimum 5s delay between the last reading and current request is enforced, if this request is less than 5s than the previous one, then the last known value is returned, else the controller is requested to perform the calculation and the new value is returned.
This should not cause any issues and overcomes problems in some releases of FocusMax (the latest version of which has been modified so that temp requests every second can be disabled/configured)
There is no need to request temperature every second, let alone 5s. Even for temperature compensation, due to the thermal dynamics of the focuser (which is where the temp probe is meant to be located), there is not going to be that much of change in temperature in 5s (due to the mass and thermal characterics of the metal used).
So this code prevents any client application from unnecessarily slowing down the controller. If it is sending heaps of temperature requests in quick succession then clearly this is an issue and the developer of the client application needs to be informed and asked to explain why this is necessary.
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
30082015 Ok, if you had not taken notice of the changes, here is the desired course of action
Read the last few prior update posts----- for your edification and background awareness
Download the latest pdf - there have been some significant additions over the last month and they are well documented now.
Update everything
Update to the latest version myFocuser2WinApp, myFocuser2MiniApp, ASCOM drivers, WinASCOMApp and if you are using a temperature probe (MT or F .ino code) then the v208 Arduino firmware. No need to update Arduino firmware for any of the M options (no temp probe). Rememeber to note down your focuser settings before upgrading. Preferred method is to uninstall previous version before installing new one (mandatory if you have not been updating regularly on each release).
You will probably notice little change but a lot of code is now different and much cleaner, better logging and better recovery in the unlikely event of an issue. So if something goes wrong, then we can find the problem past, and in the majority of evets, should be able to continue gracefully.
There are no further planned changes in the pipeline at this time. So the code should be in a stable state for some time (barring another brainwave or user request).
Report any bugs or odd behaviour direct to me please
Cheers
Robert
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Hi Robert,
first of all thanks for your effort: this is the most complete project I have found so far. I already bought the components from a previous focuser project before I have found your and this is what I have:
Arduino UNO rev 3, DRV8825, this stepper: http://www.kysanelectronics.com/Products/datasheet_display.php?recordID=7850
I haven't found any schema about UNO+DRV8825, as you know UNO can be externally powered by 12V, do you think is possible to get the 12v for the DRV8825 directly from Arduino? If so do you have any suggestion?
For the stepper I can't understand the sheet you see in the link because there is no rated current so I don't know how to tune the DRV8825 trimmer, what would you do?
Thanks in advance for your time.
Best Regards,
Giovanni.
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Hi Giovanni
Your stepper is rated at 4.2VDC and 1.6A
The volts are low and the current is high. It will probably get very hot running at 12VDC
You would need a heatsink on the DRV8825. It will get hot as this is at the upperlimit capacity for the DRV8825.
One normally sets the curent to 70%. This is done by enabling full steps and measuring coil current in one phase, and adjusting pot to 70% of the rated current (70% of 1.6A). In your case its a bit more complicated because the motor is not rated for 12V but 4.2V
The latest myFocuser design moving forward is now the Nano+DRV8825_HW203 version. It has the nano+drv8825 all on the same board layout, compact and versatile. The same board layout supports all features (minimal, full, lcd, temp probe, tft, bluetooth etc) - so you build the base board then decide what options you want (simply plug in a temp probe and lcd by adding the extra connectors and changing the firmware)
The 12V powers the Nano (via 15ohm and Zener to 9.1V) and the DRV8825 and Stepper Motor.
Yes you could use a UNO. I would use a blank prototype shield and mount the DRV8825 and other components for it (I have not done this or a layout but its been on my mind as an option) on the shield. Then plug the sheild into a UNO. It needs soldering so one may as well just use a Nano board instead if soldering. If one used the same connections as per HW203 version then the firmware would work without change.
Cheers
Robert
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Hi Robert,
thansk for your reply! I think I'll buy Nano even because I'd like to implement your solution about dew controller too so I'll buy two boards. I'm considering to change the stepper because of the current and I think the one I have could generate more vibration. Looking at an economic substitution I saw a stepper with this specs:
Angle step: 1,8°
numeber of steps: 200
Volts: 12V
Current: 0,4A
phase resistance: 30 ohm
phase inductance: 37 mH
torque: 2600 g.cm
What do you think? May it fit?
Many thanks :)
Cheers!
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Hi Giovanni
Depends on the f-ratio of your telesecope. If say f6 or less you are best with PG27 geared NEMA17.And need to microstep it.
There are links to the recommended steppers in the PDF. Look at recommended steppers, microstepping, torque and focuser connection
I assume you will be using the DRV8825
The motor has voltage and current fine, depends on heavy your imaging train is as to whether the focuser will have enough power to lift/move. What is the weight of your imaging train (does it include filter wheels etc). What is size of focuser (2", 2.5" or 3").? How do you intend to attach motor to focuser? (Belt drive, direct connect? other)
The stepper motor will end up being the most cost. The other parts are cheap. If you make a mistake you can always by another stepper motor later. But the recommended PG27 in the PDF is the best and will be trouble free with ample power for 3" focusers and filter wheels and low f-ratio scopes.
Cheers
Robert
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I actually use
NEMA17-PG27
HW203-DRV885-nano microstepped at 1/2 steps
on all my scopes now (from f5.6 to f7) with some big focusers and heavy imaging trains without any issues at all. Very reliable and consistent.
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Hi Robert,
I'll have a look to PG27 size and if it fits to my adapter used to connect to the focuser. I will work on a SC at f10 or f20 for Hi-Res planetary and I'll use only a filterwheel and the ASI 120 camera. Most of the time I'll use a Barlow. I use a 2" Cryford focuser, its weight is 860gr. I already have pulley and belt for it.
Cheers,
Giovanni.
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
30-Oct-2015
Arduino Firmware rev 212 - please update
ASCOM drivers v212 - please update
Windows Applications -v2123 and for mini v2107 - please update
There has been a slight protocol change to fix an earlier bug, as well as changes made that will support additional functions that might be introduced down the track in later versions.
Do not use the new windows apps and ascom drivers with the older firmware.
As usual, older versions will no longer supported.
BTW - a keen eye will see support added for the RAPS128 driver board (pin compatible with the DRV8825 driver board).
Robert
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Hi Robert, first of all, many thanks for your tremendous work !
I'm trying to rebuild the schematic using Eagle to have a better understanding of the project, but I'm not very familiar with PCB building, so I have a question about the schematic of the nano+drv8825 full.
In fact I am not able to find a DRV8825 eagle library similar to the one you are using and when I compare it with the pinout of the DRV8825 available on the internet, it seems it is inverted compare to your schematic.
Did i misunderstand someting on your schematic regarding the DRV8825 connections ?
Best regards
Franck
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Hi Franck
I could not find the correct eagle part for a DRV8825 board, the one I used had all the pin numbers and labels all mixed up. So do not take the EAGLE schematic as truth because the part has all the wires and labels wrong. The PCB works as I have just finished making one based on the PCB and DRV8825 Full version.
02 Dec 2015. New ASCOM v213 drivers, New Windows Apps, New PDF. A number of very worthwhile updates, including you can now turn on 12VDC BEFORE connecting USB (a good option for remote observatories). Use with most recent Arduino firmware posted 15112015.
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
15Dec2015 new v216 Arduino firmware, all versions. New Windows App. New ASCOM driver v215. Changes related to saving motorspeed values and updating controller on connect, error logging, handling invalid comports, as well as window positions being saved and restored, major changes to Arduino loop() code, no longer using software counters to determine refresh rates of displays, plus new motor speed values etc
Last edit: brownrb 2015-12-14
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02072015 New pdf, new miniapp, supports up to 4 preset focuser positions
13072015 New ASCOM drivers uploaded. Recommended to update if using FocusMax
14-07-2015 Arduino Firmware v207 for all FULL versions with temperature probe. Overcomes issue when used with FocusMax. Recommend install new firmware and update to latest ASCOM driver release.
01082015 - New Updates - new document pdf. New DRV8825 HW203 versions, layout, schematic, firmware files (has nao + drv8825 on same stripboard), new TFT_2.2 files, new windows application, new bluetooth files, docs, firmware, layout, schematic (based on DRV8825-HW203 version)
28082015 New Windows and Windows Mini applications. Code changes consolidated - a lot of changes under the hood for better reliability and error handling. Remove older versions using control panel prior to installing these latest versions.
29082015 WindowsASCOMApp tester program critical update.
I am also making changes to the ASCOM drivers and will post the new versions in the next few days.
Note: BWOE
The recent changes have been/are to ensure that conformity exists across all software releases (mydcfocuser, myfocuser, myfocuser2) in the way that exception handling and logging is performed. Early releases left out some of the critical error handling (only a problem if nothing goes wrong) - and so these changes should make it much more resilient and recoverable in the unlikely event of some unexpected exception occurring. Am trying to cover most unlikely scenarios that in the majority of cases users will not experience, but if they do, it will be logged and the application/driver should be able to recover.
Please ensure you upgrade to all the new application/driver releases as they are made available - there is no support for prior releases.
30082015 New myFocuser2ASCOM drivers (and ASCOM Conform validation) uploaded.
Update to this release.
Note: in reading temperature, there is sometimes about a 1-2s delay as the controller performs the calculation. If an application repeatedly calls GetTemp then this can slow down the controller. Hence, when a GetTemp request is issued, if the focuser is moving then the last known reading is returned. If the focuser is not moving, then a timestamp is used such that a minimum 5s delay between the last reading and current request is enforced, if this request is less than 5s than the previous one, then the last known value is returned, else the controller is requested to perform the calculation and the new value is returned.
This should not cause any issues and overcomes problems in some releases of FocusMax (the latest version of which has been modified so that temp requests every second can be disabled/configured)
There is no need to request temperature every second, let alone 5s. Even for temperature compensation, due to the thermal dynamics of the focuser (which is where the temp probe is meant to be located), there is not going to be that much of change in temperature in 5s (due to the mass and thermal characterics of the metal used).
So this code prevents any client application from unnecessarily slowing down the controller. If it is sending heaps of temperature requests in quick succession then clearly this is an issue and the developer of the client application needs to be informed and asked to explain why this is necessary.
30082015 Ok, if you had not taken notice of the changes, here is the desired course of action
Read the last few prior update posts----- for your edification and background awareness
Download the latest pdf - there have been some significant additions over the last month and they are well documented now.
Update everything
Update to the latest version myFocuser2WinApp, myFocuser2MiniApp, ASCOM drivers, WinASCOMApp and if you are using a temperature probe (MT or F .ino code) then the v208 Arduino firmware. No need to update Arduino firmware for any of the M options (no temp probe). Rememeber to note down your focuser settings before upgrading. Preferred method is to uninstall previous version before installing new one (mandatory if you have not been updating regularly on each release).
You will probably notice little change but a lot of code is now different and much cleaner, better logging and better recovery in the unlikely event of an issue. So if something goes wrong, then we can find the problem past, and in the majority of evets, should be able to continue gracefully.
There are no further planned changes in the pipeline at this time. So the code should be in a stable state for some time (barring another brainwave or user request).
Report any bugs or odd behaviour direct to me please
Cheers
Robert
Hi Robert,
first of all thanks for your effort: this is the most complete project I have found so far. I already bought the components from a previous focuser project before I have found your and this is what I have:
Arduino UNO rev 3, DRV8825, this stepper:
http://www.kysanelectronics.com/Products/datasheet_display.php?recordID=7850
I haven't found any schema about UNO+DRV8825, as you know UNO can be externally powered by 12V, do you think is possible to get the 12v for the DRV8825 directly from Arduino? If so do you have any suggestion?
For the stepper I can't understand the sheet you see in the link because there is no rated current so I don't know how to tune the DRV8825 trimmer, what would you do?
Thanks in advance for your time.
Best Regards,
Giovanni.
Hi Giovanni
Your stepper is rated at 4.2VDC and 1.6A
The volts are low and the current is high. It will probably get very hot running at 12VDC
You would need a heatsink on the DRV8825. It will get hot as this is at the upperlimit capacity for the DRV8825.
One normally sets the curent to 70%. This is done by enabling full steps and measuring coil current in one phase, and adjusting pot to 70% of the rated current (70% of 1.6A). In your case its a bit more complicated because the motor is not rated for 12V but 4.2V
The latest myFocuser design moving forward is now the Nano+DRV8825_HW203 version. It has the nano+drv8825 all on the same board layout, compact and versatile. The same board layout supports all features (minimal, full, lcd, temp probe, tft, bluetooth etc) - so you build the base board then decide what options you want (simply plug in a temp probe and lcd by adding the extra connectors and changing the firmware)
I power the nano from 12V, no need for uno, see
http://sourceforge.net/projects/arduinoascomfocuserpro2diy/files/DRV8825_HW203/myFocuser_hw203_DRV8825_Full_schem.jpg/download
The 12V powers the Nano (via 15ohm and Zener to 9.1V) and the DRV8825 and Stepper Motor.
Yes you could use a UNO. I would use a blank prototype shield and mount the DRV8825 and other components for it (I have not done this or a layout but its been on my mind as an option) on the shield. Then plug the sheild into a UNO. It needs soldering so one may as well just use a Nano board instead if soldering. If one used the same connections as per HW203 version then the firmware would work without change.
Cheers
Robert
Hi Robert,
thansk for your reply! I think I'll buy Nano even because I'd like to implement your solution about dew controller too so I'll buy two boards. I'm considering to change the stepper because of the current and I think the one I have could generate more vibration. Looking at an economic substitution I saw a stepper with this specs:
Angle step: 1,8°
numeber of steps: 200
Volts: 12V
Current: 0,4A
phase resistance: 30 ohm
phase inductance: 37 mH
torque: 2600 g.cm
What do you think? May it fit?
Many thanks :)
Cheers!
Hi Giovanni
Depends on the f-ratio of your telesecope. If say f6 or less you are best with PG27 geared NEMA17.And need to microstep it.
There are links to the recommended steppers in the PDF. Look at recommended steppers, microstepping, torque and focuser connection
I assume you will be using the DRV8825
The motor has voltage and current fine, depends on heavy your imaging train is as to whether the focuser will have enough power to lift/move. What is the weight of your imaging train (does it include filter wheels etc). What is size of focuser (2", 2.5" or 3").? How do you intend to attach motor to focuser? (Belt drive, direct connect? other)
The stepper motor will end up being the most cost. The other parts are cheap. If you make a mistake you can always by another stepper motor later. But the recommended PG27 in the PDF is the best and will be trouble free with ample power for 3" focusers and filter wheels and low f-ratio scopes.
Cheers
Robert
I actually use
NEMA17-PG27
HW203-DRV885-nano microstepped at 1/2 steps
on all my scopes now (from f5.6 to f7) with some big focusers and heavy imaging trains without any issues at all. Very reliable and consistent.
Hi Robert,
I'll have a look to PG27 size and if it fits to my adapter used to connect to the focuser. I will work on a SC at f10 or f20 for Hi-Res planetary and I'll use only a filterwheel and the ASI 120 camera. Most of the time I'll use a Barlow. I use a 2" Cryford focuser, its weight is 860gr. I already have pulley and belt for it.
Cheers,
Giovanni.
15092015 New Arduino Firmware v210 for all controllers with temperature probes. New Windows and Windows Mini apps. New ASCOM drivers v211.
30-Oct-2015
Arduino Firmware rev 212 - please update
ASCOM drivers v212 - please update
Windows Applications -v2123 and for mini v2107 - please update
There has been a slight protocol change to fix an earlier bug, as well as changes made that will support additional functions that might be introduced down the track in later versions.
Do not use the new windows apps and ascom drivers with the older firmware.
As usual, older versions will no longer supported.
BTW - a keen eye will see support added for the RAPS128 driver board (pin compatible with the DRV8825 driver board).
Robert
10112015 New documentation PDF, new arduino firmware v213 for every build option, new updated PCB files, new windows apps
Hi Robert, first of all, many thanks for your tremendous work !
I'm trying to rebuild the schematic using Eagle to have a better understanding of the project, but I'm not very familiar with PCB building, so I have a question about the schematic of the nano+drv8825 full.
In fact I am not able to find a DRV8825 eagle library similar to the one you are using and when I compare it with the pinout of the DRV8825 available on the internet, it seems it is inverted compare to your schematic.
Did i misunderstand someting on your schematic regarding the DRV8825 connections ?
Best regards
Franck
Hi Franck
I could not find the correct eagle part for a DRV8825 board, the one I used had all the pin numbers and labels all mixed up. So do not take the EAGLE schematic as truth because the part has all the wires and labels wrong. The PCB works as I have just finished making one based on the PCB and DRV8825 Full version.
The schematic here is
https://sourceforge.net/projects/arduinoascomfocuserpro2diy/files/DRV8825_HW203/
shows correct.
Hi Robert,
Thanks a lot for replying. The picture you provided will be very helpfull !
Best Regards
Franck
15112015 Major bug fixes to all arduino firmwares. Upgrade to latest version is essential.
02 Dec 2015. New ASCOM v213 drivers, New Windows Apps, New PDF. A number of very worthwhile updates, including you can now turn on 12VDC BEFORE connecting USB (a good option for remote observatories). Use with most recent Arduino firmware posted 15112015.
07 Dec 2015 New ASCOM drivers released, conform with ASCOM62
15Dec2015 new v216 Arduino firmware, all versions. New Windows App. New ASCOM driver v215. Changes related to saving motorspeed values and updating controller on connect, error logging, handling invalid comports, as well as window positions being saved and restored, major changes to Arduino loop() code, no longer using software counters to determine refresh rates of displays, plus new motor speed values etc
Last edit: brownrb 2015-12-14
30122015 New Windows App and Mini App, plus new PDF. Fixed some strange bugs. Please upgrade
USE CONTROL PANEL TO REMOVE THE EXISTING 274 or less DRIVER. YOU MUST DO THIS BEFORE INSTALLING v275
Last edit: brownrb 2020-10-07