Hello Robert
I am at the stage of getting the parts together for your build which looking at the detail you have provided i can only thank you for, i have a couple of questions if i can...is the nema 17 in your parts list still the recomended motor? the motor will be on an ED80 pro moving a focal reducer, ZWO1600 and 8 filter wheel and i will be using your design with APT for auto focus to make life easier with all the filters, it will be replacing a skywatcher auto focus motor and although reliable im limited with APT for a good auto focus with it not being a stepper, i have also looked at many peoples designs over the weeks that again recommend the Nema but at 5:1, 27:1, even 71:1 with the planetary gearbox and was hoping you could point me in the right direction if your choice is different now from your original motor?, its the autofocus im after and not bothered in chasing the whole rack and pinion.. :)...also if its any use i will be replacing the stock dual speed ED80 focuser with the dual speed 2" crayford focuser...although im still undecided if thats a good move or not..
Thanks again for your time Robert, its much appreciated
All the best
Wayne
Last edit: Wayne Brady 2018-11-02
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Hi Wayne
Comes down to CFZ and what is needed to get 5-10 steps within that. I do not like to go over 1/4 stepping so that means in most cases with a fast f-ratio using a PG5 Nema.
I now prefer the NEMA 14 with 0.9d at 1/2 or 1/4 stepping, but again depends on f-ratio
I know the extra weight of the NEMA17. I operated a NEMA17-PG5 on an ED-80-CF refractor, no issues with extra weight, but I had that on a skywatcher EQ8 which is an awesome mount for the price, you could probably mount a double decker bus on it and it wouldnt miss a beat, one hell of a mount.
With all that weight of reducer, filter wheel, camera etc I would go with a geared motor - it will slip much less (if at all) when pointing upwards
Regards
Robert
Last edit: brownrb 2018-11-03
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Thanks Robert, in the excitement i flicked through your documentaion and half didnt sink in...just read again and its there clear as day...or night if your blessed..Nema 17 27:1 is looking like the motor for me, i have the AZ-EQ6, not as robust as the EQ8 but still packs a punch so no worries with the weight....time to release the purse strings ;)
Just one more thing, you suggest the DRV8825 with this motor but is there any reason i cant use the Adafruit motorshield or similar makes for my R3 Uno?...reason being i just already have them..
Thanks again for the info
Wayne
Last edit: Wayne Brady 2018-11-03
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The doc/pdf is designed for all to read at least a couple of times - there is one hell of a lot of info in there. The videos on youtube are a good explainer. At times I even have to go back and re-read (but in my case it could be old age..)
A lot of the newer motor shields do not work. Try to look for the old ones like in the document. I think there are still some on aliexpress.
Stay away from the newer xxxxP models. I just dont have the time to write the software for these (or the money to purchase the boards in the first place).
Not sure if the newer adafruit board works - anyone care to chime in?
Regards
Robert
Last edit: brownrb 2018-11-03
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The reason i ask is one of the videos i looked at recently was this one which used the Adafruit with a Nema17...but im not sure if its doing what we want it to do or just forwards-backwards if you know what i mean... https://youtu.be/ddewI9dD2VA
Last edit: Wayne Brady 2018-11-03
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There are mutilpe versions of the Adafruit board, v1, v2 etc as well as the newer 293P boards. They are NOT all the same, wired differently etc, so code has to be specific to each board or it does not go.
Our example referes to the older v1 board. Adafruit no longer sells these.
Last edit: brownrb 2018-11-03
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Im sure as hell glad you know what your doing Robert, it would seem im trying to jump too high...so in a nutshell, any of the above 3 links assuming they ship to the UK will do what i want with my R3 Uno and YOUR code?...and if i buy a few it will tie me over for a while....
Thanks yet again for your time.....and patience :s
Is that not the V1.0 printed on the boards Robert? if not where is the revision located on them? i will get the one above ordered if there isnt any local, its not the cost that bothers me but the month long wait these things normaly take to get here..
Thanks..
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Your not on your own mate, i got my daughter to double check for me.. they are a couple of quid more but at least i can start building by the end of the week..thanks again for your time Robert its much appreciated.
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Robert am i right in assuming that the Arduino board and sheild cannot run on a 13.8v bench supply? i know it states 12v but thats what im running the mount/camera on was hopeing to plug this in like the hitech astro i was using...if not that explains the whisp of smoke :)....all seemed to be fine then started losing the device in COM...a couple of restarts seemed to bring it back then pot luck i was in device manager... i heard the usb disconnect and com5 disappear....then the whisp :)
I have tried the arduino on another computer, all lights up on the board but getting Board at COM5 is not available, the motor sounded noisy as well, like there wasnt enough juice going to it to move the focuser so assume i blown it?
cheers
Last edit: Wayne Brady 2018-11-24
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Hi Wayne
Welcome to the smoke club. I have fried an easydriver that glowed so red it caught fire, literally.
I would suspect you have blown the onboard 5V regulators on the Arduino, difficult to replace
When it says the shield can take like 30V it only means the stepper motor chip itself, not other parts on the board.
I find that most Arduino boards will not hande more than 12V. Best replace it.
You could use a 7812 regulator to drop the 13.8V to 12V first before going into the arduino. Ot you can one of those on ebay which will regulate 12V. Either way, 13.8V is too much.
Regards
Robert
Last edit: brownrb 2018-11-25
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Haha smoke club...i like it, thanks for the advice a couple are now on order...you know just in case the smoke club takes off :) i have a couple of those volt regulators that i used to reduce the volts down to 7.4 for my Canon camera..you know the ones with a screw tab and you turn it to reduce or increase the volts, i cannot remember the name of them it was a while ago now, nothing special they just fit inline from the 12vDC...would that do?
Found it..LM2596 DC-DC
Last edit: Wayne Brady 2018-11-25
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Thanks guys, will get it sorted for weekend trials, anyway nearing completeion here is the nearly finished project, no buttons/lcd as this will be use in the observatory purely with Ascom and Skywatcher ED80 Pro
Thanks
Cheers Robert
The case is a Perancea 8 pin plug-in case that i butchered, took a 22mm hole saw to the pins on the case which just happens to be about the size of the rounded front on the planetary gearbox/motor bracket, the front of the case thats bolted through the bracket is glass filled nylon so can give it a bit of hammer..its a tight fit but gives around 5mm at the back end for the cable.
Last edit: Wayne Brady 2018-11-26
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Robert can i do a quick check on the power connection before i fry more boards :)..i can plug the 12v into the arduino board to power the shield and motor as i was doing before the smoke? i assumed it was the 13.8v that fried the board, the reason i ask there is also external power ports on the L293D so not sure which is the best route? either through the Arduino or L293D direct?
Thanks
Last edit: Wayne Brady 2018-11-29
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Im getting it around my neck a bit with this, the shield just clips onto the top of the R3 uno and i am not using any other accessories other than the motor so i assumed the 12v just goes to the two screw connectors on the shield and the 4 motor wires to M3 and M4?, i will question the info sent with the shield as they said i could just power the shiled and motor through the Arduino 7-12vDC imput like this..
Hello Robert
I am at the stage of getting the parts together for your build which looking at the detail you have provided i can only thank you for, i have a couple of questions if i can...is the nema 17 in your parts list still the recomended motor? the motor will be on an ED80 pro moving a focal reducer, ZWO1600 and 8 filter wheel and i will be using your design with APT for auto focus to make life easier with all the filters, it will be replacing a skywatcher auto focus motor and although reliable im limited with APT for a good auto focus with it not being a stepper, i have also looked at many peoples designs over the weeks that again recommend the Nema but at 5:1, 27:1, even 71:1 with the planetary gearbox and was hoping you could point me in the right direction if your choice is different now from your original motor?, its the autofocus im after and not bothered in chasing the whole rack and pinion.. :)...also if its any use i will be replacing the stock dual speed ED80 focuser with the dual speed 2" crayford focuser...although im still undecided if thats a good move or not..
Thanks again for your time Robert, its much appreciated
All the best
Wayne
Last edit: Wayne Brady 2018-11-02
Hi Wayne
Comes down to CFZ and what is needed to get 5-10 steps within that. I do not like to go over 1/4 stepping so that means in most cases with a fast f-ratio using a PG5 Nema.
I now prefer the NEMA 14 with 0.9d at 1/2 or 1/4 stepping, but again depends on f-ratio
I know the extra weight of the NEMA17. I operated a NEMA17-PG5 on an ED-80-CF refractor, no issues with extra weight, but I had that on a skywatcher EQ8 which is an awesome mount for the price, you could probably mount a double decker bus on it and it wouldnt miss a beat, one hell of a mount.
With all that weight of reducer, filter wheel, camera etc I would go with a geared motor - it will slip much less (if at all) when pointing upwards
Regards
Robert
Last edit: brownrb 2018-11-03
Thanks Robert, in the excitement i flicked through your documentaion and half didnt sink in...just read again and its there clear as day...or night if your blessed..Nema 17 27:1 is looking like the motor for me, i have the AZ-EQ6, not as robust as the EQ8 but still packs a punch so no worries with the weight....time to release the purse strings ;)
Just one more thing, you suggest the DRV8825 with this motor but is there any reason i cant use the Adafruit motorshield or similar makes for my R3 Uno?...reason being i just already have them..
Thanks again for the info
Wayne
Last edit: Wayne Brady 2018-11-03
Hi Wayne
The doc/pdf is designed for all to read at least a couple of times - there is one hell of a lot of info in there. The videos on youtube are a good explainer. At times I even have to go back and re-read (but in my case it could be old age..)
A lot of the newer motor shields do not work. Try to look for the old ones like in the document. I think there are still some on aliexpress.
Stay away from the newer xxxxP models. I just dont have the time to write the software for these (or the money to purchase the boards in the first place).
Not sure if the newer adafruit board works - anyone care to chime in?
Regards
Robert
Last edit: brownrb 2018-11-03
The reason i ask is one of the videos i looked at recently was this one which used the Adafruit with a Nema17...but im not sure if its doing what we want it to do or just forwards-backwards if you know what i mean...
https://youtu.be/ddewI9dD2VA
Last edit: Wayne Brady 2018-11-03
Hi Wayne
That video is for the EQFocuser project - not the same. Different code, different author, different circuit etc.
Our example is
https://www.youtube.com/watch?v=Ap4k-0QlNwQ
https://www.youtube.com/watch?v=MaQzxvlpFWE
There are mutilpe versions of the Adafruit board, v1, v2 etc as well as the newer 293P boards. They are NOT all the same, wired differently etc, so code has to be specific to each board or it does not go.
Our example referes to the older v1 board. Adafruit no longer sells these.
Last edit: brownrb 2018-11-03
See
https://www.ebay.com/itm/Expansion-card-L293D-motor-drive-Shield-for-Arduino-blue-N5V1/282658185698?epid=627907968&hash=item41cfbda1e2:g:VLQAAOSwe0NZvzG0:rk:2:pf:1
https://www.ebay.com/itm/Expansion-card-L293D-motor-drive-Shield-for-Arduino-blue-F4V1/292631756738?epid=703338191&hash=item4422363fc2:g:v3gAAOSwLWBbP-93:rk:4:pf:1&frcectupt=true
https://www.ebay.com/itm/Motor-Servo-Schrittmotor-Control-Shield-v1-0-L293D/142015467710?hash=item2110c810be:g:EJcAAOSwY0lXTHwF:rk:5:pf:1&frcectupt=true
Im sure as hell glad you know what your doing Robert, it would seem im trying to jump too high...so in a nutshell, any of the above 3 links assuming they ship to the UK will do what i want with my R3 Uno and YOUR code?...and if i buy a few it will tie me over for a while....
Thanks yet again for your time.....and patience :s
Sorry Robert, a bit closer if these are the ones?
https://www.ebay.co.uk/itm/New-L293D-Motor-Drive-Shield-for-Arduino-UNO-Mega-Due-UK-stock/161846320446?hash=item25aecadd3e:g:FVkAAOSwFnFV8v6K:rk:13:pf:0
Last edit: Wayne Brady 2018-11-03
There is no revision number on the board
I would be tempted to go for the cheapest
https://www.ebay.co.uk/itm/L293D-NodeMCU-IC-Motor-Expansion-Board-For-Arduino-UNO-MEGA2560-ESP8266-ESP-12E/292004170391?hash=item43fcce0a97Ⓜ️mPFWfcZ-CMFK8tx9tieoERA:rk:2:pf:1&frcectupt=true
chose L293D at 1.59
That way if it doesnt work it is only a small cost.
Is that not the V1.0 printed on the boards Robert? if not where is the revision located on them? i will get the one above ordered if there isnt any local, its not the cost that bothers me but the month long wait these things normaly take to get here..
Thanks..
Your eyesight is way better than mine!
Damn if I didnt look multiple times and never saw it!
Your not on your own mate, i got my daughter to double check for me.. they are a couple of quid more but at least i can start building by the end of the week..thanks again for your time Robert its much appreciated.
Robert am i right in assuming that the Arduino board and sheild cannot run on a 13.8v bench supply? i know it states 12v but thats what im running the mount/camera on was hopeing to plug this in like the hitech astro i was using...if not that explains the whisp of smoke :)....all seemed to be fine then started losing the device in COM...a couple of restarts seemed to bring it back then pot luck i was in device manager... i heard the usb disconnect and com5 disappear....then the whisp :)
I have tried the arduino on another computer, all lights up on the board but getting Board at COM5 is not available, the motor sounded noisy as well, like there wasnt enough juice going to it to move the focuser so assume i blown it?
cheers
Last edit: Wayne Brady 2018-11-24
Hi Wayne
Welcome to the smoke club. I have fried an easydriver that glowed so red it caught fire, literally.
I would suspect you have blown the onboard 5V regulators on the Arduino, difficult to replace
When it says the shield can take like 30V it only means the stepper motor chip itself, not other parts on the board.
I find that most Arduino boards will not hande more than 12V. Best replace it.
You could use a 7812 regulator to drop the 13.8V to 12V first before going into the arduino. Ot you can one of those on ebay which will regulate 12V. Either way, 13.8V is too much.
Regards
Robert
Last edit: brownrb 2018-11-25
Haha smoke club...i like it, thanks for the advice a couple are now on order...you know just in case the smoke club takes off :) i have a couple of those volt regulators that i used to reduce the volts down to 7.4 for my Canon camera..you know the ones with a screw tab and you turn it to reduce or increase the volts, i cannot remember the name of them it was a while ago now, nothing special they just fit inline from the 12vDC...would that do?
Found it..LM2596 DC-DC
Last edit: Wayne Brady 2018-11-25
I used a L7808 if I'm not wrong
7808 is also a good choice
Thanks guys, will get it sorted for weekend trials, anyway nearing completeion here is the nearly finished project, no buttons/lcd as this will be use in the observatory purely with Ascom and Skywatcher ED80 Pro
Thanks
Hi Wayne
Pretty fine work there - if my first focuser I built was as good as that I wouldve been mightly chuffed! Did you 3d print the case?
Best wishes for your first light with the focuser.
Regards
Robert
Last edit: brownrb 2018-11-26
Cheers Robert
The case is a Perancea 8 pin plug-in case that i butchered, took a 22mm hole saw to the pins on the case which just happens to be about the size of the rounded front on the planetary gearbox/motor bracket, the front of the case thats bolted through the bracket is glass filled nylon so can give it a bit of hammer..its a tight fit but gives around 5mm at the back end for the cable.
Last edit: Wayne Brady 2018-11-26
Impressive.
Best wishes with the focuser
Robert
Robert can i do a quick check on the power connection before i fry more boards :)..i can plug the 12v into the arduino board to power the shield and motor as i was doing before the smoke? i assumed it was the 13.8v that fried the board, the reason i ask there is also external power ports on the L293D so not sure which is the best route? either through the Arduino or L293D direct?
Thanks
Last edit: Wayne Brady 2018-11-29
Follow the wiring.
12V goes to VIN on the shield board and to the 2P screw connector on the
motor sheild board as shown.
Im getting it around my neck a bit with this, the shield just clips onto the top of the R3 uno and i am not using any other accessories other than the motor so i assumed the 12v just goes to the two screw connectors on the shield and the 4 motor wires to M3 and M4?, i will question the info sent with the shield as they said i could just power the shiled and motor through the Arduino 7-12vDC imput like this..
So I assume you did not make the sub-board then just decided to try some shortcuts?