Showcase: Built With OnStep


 

I've attached a writeup of my OnStep modifications to my iOptron SmartStar PR mount. 
See at http://rhizotech.net/Astro/SmartStar-OnStep_mods.pdf


Khalid Baheyeldin
 

On Fri, Jul 19, 2019 at 11:15 PM, Richard Shagam wrote:
I've attached a writeup of my OnStep modifications to my iOptron SmartStar PR mount. 
Thanks for sharing. I added it to the Showcase page.
Very nice image too ...

Question on the STM32 Blue Pill case: is that 3D printed too? Can you post the link to the design?
For the T7 guide camera, is it USB 2.0 or 3.0? Did you flash it with the ZWO firmware?


Michael E. Burk
 

Khalid. Both are already on thingyverse:

STM32 Blue Pill Case:


SHC Case:


 


 

Question on the STM32 Blue Pill case: is that 3D printed too? Can you post the link to the design?
For the T7 guide camera, is it USB 2.0 or 3.0? Did you flash it with the ZWO firmware?
Both cases were printed from designs on Thingiverse:  https://www.thingiverse.com/thing:3610920 for the Blue PIll case, and https://www.thingiverse.com/thing:3534640 for the hand controller.  The Blue Pill case design needs some work on the front plate, but I just had my friend print out a back plate and I'll cut appropriate holes.
The T7 guide camera is USB2.  I didn't reflash the camera firmware itself, however it is compatible with ZWO ASI drivers, which I recall that I downloaded from the ZWO website (I bought it a year ago).  I don't believe I used the drivers that came with the camera, if there were any.  I'm always leary about flashing firmware--the camera worked as stock, so why mess with it?


Roman Hujer
 


George Cushing
 

Very nice Roman!

Today I tested a MiniPCB v. 1.27 that is intended to replace a friend's dead Vixen dual drive controller. My friend says he just want to replace his controller, no goto desired. In considering the project I realized the least troublesome way to get it done was with the MiniPCB. The $22 Teensy 3.2 is the most dear part. The rest comes in at less than $10. By leaving out the unneeded parts assembly was quick and easy. 

Adding the basic hand control and a couple of standard sized project boxes finishes the kit. Just have to make up the cables for the MT1 step motors. For testing I used a couple of NPM PF42 7.5° pulled from old Celestron Powerstar mounts. I removed the 300:1 gearheads, so I could see the motors turning.

Here are the values I used:
Mount type: GEM
Board: MiniPCB
Axis 1:
   Worm wheel steps/rotation:  144.0
   Transfer gear/pulley ratio: 120.0
   Motor Steps/Rotation:       48
   Microsteps when tracking:   4
   Microsteps when slewing :   1
   Stepper Driver Model:       DRV8825
 Axis 2:
   Worm wheel steps/rotation:  144.0
   Transfer gear/pulley ratio: 120.0
   Motor Steps/Rotation:       48
   Microsteps when tracking:   4
   Microsteps when slewing:    1
   Stepper Driver Model:       DRV8825
Max Rate:                     26
PEC Buffer Size:              600


Chris Vaughan
 

Very nice Roman. What do you fill you lettering in with? I've tried a few things and none of them look pretty.


Roman Hujer
 

Children's water-based paint "Tempera" ;-)


Roman Hujer
 

My new adaptation EQ5 (SkyWatcher) telescope mount to OnStep https://www.thingiverse.com/thing:4170058 Roman


Jay Murphy
 

Nice job.


Mike Ahner
 

Very nice, Roman!

But.... you're making some of us feel completely inadequate when we haven't completely finished our first conversion, let alone 3... :)
-Mike


Khalid Baheyeldin
 

Thanks Roman,

I added it to the showcase page on the Wiki.

One question about the polar scope reticle: did you get it to work with the STM32 (PWM for brighter/dimmer)?
There is no code yet for this, so wondering if you got it working.


Roman Hujer
 

Hi Khaid, retilcle 3mm red LED is serial connect with 1kΩ rezsitor. I first time conneted to reticle pin and GND - but diimmer button working reverse. Now connect to 3v3 pin and reticle pin - dimmer botton working OK.
In config file set #define RETICULE_LED_PINS 128 Roman


Roman Hujer
 

I also designed a new universal PCB for BT module into MiniPCB2 and STM32. Jupers are used to select the serial interface. https://easyeda.com/hujer.roman/bt_for_minipcb2

Roman


Dave Schwartz
 

OnStep LEDs are connected between +ve and the MCU pin (with the appropriate limiting resistor). The LED illuminates when the pin is pulled low... the MCU pin is a current sink, not a source.

On 2020-02-21 2:47 a.m., Roman Hujer wrote:

Hi Khaid, retilcle 3mm red LED is serial connect with 1kΩ rezsitor. I first time conneted to reticle pin and GND - but diimmer button working reverse. Now connect to 3v3 pin and reticle pin - dimmer botton working OK.
In config file set #define RETICULE_LED_PINS 128 Roman


Khalid Baheyeldin
 

On Fri, Feb 21, 2020 at 09:31 AM, Dave Schwartz wrote:
OnStep LEDs are connected between +ve and the MCU pin (with the appropriate limiting resistor). The LED illuminates when the pin is pulled low... the MCU pin is a current sink, not a source.

 

On 2020-02-21 2:47 a.m., Roman Hujer wrote:

Hi Khaid, retilcle 3mm red LED is serial connect with 1kΩ rezsitor. I first time conneted to reticle pin and GND - but diimmer button working reverse. Now connect to 3v3 pin and reticle pin - dimmer botton working OK.
In config file set #define RETICULE_LED_PINS 128 Roman
You mean the dimming function from the Android App or SHC does actually controls brightness?

For STM32, PWM is quite different from other Arduino platforms, and requires different code, which I have not yet incorporated into the STM32 HAL.

Maybe we got lucky and standard Arduino PWM code works on STM32?


Roman Hujer
 

Yes RETICULE LED brightness controls working is very fine about ten step. My firmware is 2.22k 2019-07-19

Roman


Dave Schwartz
 

I think it's settling on NOT using PWM for heat control. Unlike LED intensity control, there is no need to switch a resistive load faster than once per few seconds... an LED on off pin like the tracking LED is sufficient as a relay or MOSFET trigger.


On February 21, 2020 12:05:02 PM EST, Khalid Baheyeldin <kbahey@...> wrote:
On Fri, Feb 21, 2020 at 09:31 AM, Dave Schwartz wrote:
OnStep LEDs are connected between +ve and the MCU pin (with the appropriate limiting resistor). The LED illuminates when the pin is pulled low... the MCU pin is a current sink, not a source.

 

On 2020-02-21 2:47 a.m., Roman Hujer wrote:

Hi Khaid, retilcle 3mm red LED is serial connect with 1kΩ rezsitor. I first time conneted to reticle pin and GND - but diimmer button working reverse. Now connect to 3v3 pin and reticle pin - dimmer botton working OK.
In config file set #define RETICULE_LED_PINS 128 Roman
You mean the dimming function from the Android App or SHC does actually controls brightness?

For STM32, PWM is quite different from other Arduino platforms, and requires different code, which I have not yet incorporated into the STM32 HAL.

Maybe we got lucky and standard Arduino PWM code works on STM32?

--
Sent from my Android device with K-9 Mail. Please excuse my brevity.


tomofreno2000
 

I made some modifications to my 22.4" Dob so it would fit into my Chevy Bolt. Mainly shortening the UTA from 18" to 8.5" which required making a new secondary holder and spider.  I'll be updating the thread on it at CN with some new photos soon. A video of it moving under OnStep control at about 3.5 deg/sec is here. The scope loaded into the Bolt with folded ramp boards along side it is shown below:


Howard Dutton
 

On Sat, Apr 25, 2020 at 08:48 AM, tomofreno2000 wrote:
I made some modifications to my 22.4" Dob so it would fit into my Chevy Bolt. Mainly shortening the UTA from 18" to 8.5" which required making a new secondary holder and spider.  I'll be updating the thread on it at CN with some new photos soon. A video of it moving under OnStep control at about 3.5 deg/sec is here. The scope loaded into the Bolt with folded ramp boards along side it is shown below:
That 'scope is just plain awesome, nice to see another EV owner on here too. ;)