My Onstep journey.

[Fish]

My onstep journey

When my LXD 75 electronics died I was left with a problem. After asking in this forum it was suggested to go the diy route but initially I discounted it because I wanted a quick fix and after reading up on the options I decided I wasnt upto the task.
After a successful temporary repair of my mount electronics I decided to have a go at DIY.
Out of the two options , Astroeq and Onstep I decided to research the latter.
Here is the wiki.
https://groups.io/g/onstep/wiki/home

At first this reads like some foreign language but dont give up , register on the forum and read. Eventualy things will start to become a little bit clear. 
After a lot of reading I decided to go with the STM32 blue pill , it seems like a neat solution and I found that you can order a full kit from here .
https://baheyeldin.com/astronomy/onstep-telescope-controller-stm32-pcb-kits.html

Thanks to Khalid and Dave for making these kits available.
Im now waiting for my kit to arrive from Canada and because of their postal strikes Im not sure how long it will be.

My intention is to log my build on here so that anyone who has been down this path can advise when im straying off course and in the hope that it may help someone else.

The first thing now is to start to decide on motors and how to mount them on my LXD 75 which is just a standard EQ5 mount.

So it would seem that stepper motors come in loads of variations . Basically for an eq5 mount that has a worm ratio of 144:1 a 400 step motor would be better with a further gear ratio of 3 : 1 between the motor and  drive so decided to go with these motors .
Bipolar Nema 17 stepper motor with step angle 0.9deg and size 42x42x39mm. It has 4 wires, each phase draws current 0.9A.
To get a gear ratio of 3:1 I needed to order the timing belt drive pulleys, it seems the most common standard used is the GT2 type so I ordered 16 tooth for the motors and 48 for the drive to give me 3:1 ratio.
Need to sort out the mounting next.
 

[Fish]

Motor mounts finnished today they use the standard EQ5 single bolt fixing.

Waiting for the postman now.

[Fish]

My kit arrived today you can download assembly instructions from the wiki.

https://groups.io/g/onstep/wiki/STM32F103-Blue-Pill

Picture of all the bits.

First job is to get everything soldered and following the sequence of assembly on the wiki made it quite an easy task. After a few hours everything soldered .

And a final picture with everything plugged in just to double check everything is ok.

 

Next task will be to make up the on board links, source a box and find out how to fit molex connectors to connect the motors. 

[Fish]

Today was programming day , after two weeks of trying to get my head arround IDE , the software used to program arduino devices.

First up was the wemos, the wifi board has its own software . Opened the sketch , set up the board type etc and flashed the program. The main thing here was that you need to press the reset button before flashing, this I did not know and it took a while of searching to find out. Apparently its the normal thing when programming arduino devices.

Next was the stm32 with the onstep program, again once the board was set up all went well . No need for reset here as it has a different set up for the usb.

Powered up the board and connected phone to onstep with phone and tab with sky safari. Did a fake alignment and all was good. Decided I wanted to connect onstep to the internet , this locked up the wemos.

So first thing this morning it was searching for solutions, tried them all in order of what seemed the less risky. As it was the last two things worked, flashing it as a generic esp8266 and then a full flash .

Eventualy everything was back up and running.

Here is a vid showing the two wifi connections with onstep app and sky safari.

Looking for a box now so that I can get it finnished and on the mount , still a few bits to sort out . More molex connections (grrrrr) the buzzer does not work and have to sort the motor cables.

 

 

 

 

Edited December 8, 2018 by Fish
Ooppssss

[Fish]

Eventually finnished all the remaining bits and sorted out the final config perameters.

Still without a box its time to get it on the mount. Everything fixed to the mount I did a goto and compared it to sky safari as it was still daylight. It looked good so a second star was chosen and again it looked good and align was successful.  Then noticed the moon was up so I did a goto to the moon. First thing that was apparent was it was slewing the wrong way then the dec motor stalled.

Back to the config and a couple of changes to the max rate saw an end to the stalling and the strange slew to the moon was the RA motor going the wrong direction, this was not as obvious as you would think.

Darkness falls so it was time for a proper test, set it to home position and did a two star align. Each alignment star, very close to central was synced then it was time to go through some of sky safaris tonights best.

Short clip of it working.

Still a bit of work left to complete and will be doing a smart hand controller next . The whole process is a lot easier than you may think and there is even an option where there is virtually no soldering. The community for onstep is great and loads of help available. My total cost was just over £119 , this is not the cheapest build  you can easily build one for under £100 .

[gazza]

Great stuff! Will be interested to see what ou think when it is under the sky....

cheers

Gary

[Fish]

Its great ?  compared to my old Meade the goto is a lot quicker. The accuracy seems to be good , I did a two star align and off we went. I set a park position as my roof will not go on in the home position and on the two occasions I have un-parked all seems to be good. 

This system has a lot more to it than the normal commercial solutions, you can alter everything on the fly. It is geared very much towards photography . Me ,I can just use the android app and sky safari and zip aground the sky clocking up all my normal targets. 

You allso have a set of web pages , as OnStep generates its own wifi , that can change and tweak tracking that I presume would be usefull for photography.

I must allso add that OnStep can be used as a finnished product , ie. build and forget just use with the stable software. 

Or , keep track of the evolution and update as required. New builds and features are being worked on all the time. OnStep itself becomes another cloudy night hobby .

[Fish]

OnStep is now finnished, in a box and waiting for clear skies ?

Very happy with the outcome and the fact that it is modular by design means I will be able to easily replace any parts in the future should they fail. 

[ninosr]

Just wondering what you used for soldering the components to the board, size and type of solder wire and what type of soldering iron and blade you used. I am just waiting on some more items before I start.

Thanks

Nino

[Fish]

Sorry had not seen this! Hope your build went well. I had the soldering equipment so no idea what the spec is just standard soldering stuff. Weller soldering iron with about 0.5mm tip .

[jmvm]

This looks cool. I've got a Lx70 manual tracking mount, which looks very similar. Looking to do the same. Where do you get the mounting hardware brackets for the motors? 

[Fish]

They were made out of aluminium angle , I think people have used the standard nema plastic brackets  

[shackers]

On 27/11/2018 at 22:26, Fish said:

My onstep journey

When my LXD 75 electronics died I was left with a problem. After asking in this forum it was suggested to go the diy route but initially I discounted it because I wanted a quick fix and after reading up on the options I decided I wasnt upto the task.
After a successful temporary repair of my mount electronics I decided to have a go at DIY.
Out of the two options , Astroeq and Onstep I decided to research the latter.
Here is the wiki.
https://groups.io/g/onstep/wiki/home

At first this reads like some foreign language but dont give up , register on the forum and read. Eventualy things will start to become a little bit clear. 
After a lot of reading I decided to go with the STM32 blue pill , it seems like a neat solution and I found that you can order a full kit from here .
https://baheyeldin.com/astronomy/onstep-telescope-controller-stm32-pcb-kits.html

Thanks to Khalid and Dave for making these kits available.
Im now waiting for my kit to arrive from Canada and because of their postal strikes Im not sure how long it will be.

My intention is to log my build on here so that anyone who has been down this path can advise when im straying off course and in the hope that it may help someone else.

The first thing now is to start to decide on motors and how to mount them on my LXD 75 which is just a standard EQ5 mount.

So it would seem that stepper motors come in loads of variations . Basically for an eq5 mount that has a worm ratio of 144:1 a 400 step motor would be better with a further gear ratio of 3 : 1 between the motor and  drive so decided to go with these motors .
Bipolar Nema 17 stepper motor with step angle 0.9deg and size 42x42x39mm. It has 4 wires, each phase draws current 0.9A.
To get a gear ratio of 3:1 I needed to order the timing belt drive pulleys, it seems the most common standard used is the GT2 type so I ordered 16 tooth for the motors and 48 for the drive to give me 3:1 ratio.
Need to sort out the mounting next.
 

Hi @Fish thanks for this, I have been looking at doing the same as you with an EQ5 mount (mine is a skywatcher so not sure if the gearing still applies?) How did you know what gearing to use? I've tried to use the onstep group but just find it a bit strange on how ot all works 🙈

I'd really like to build this but want to get everything ready first. It doesn't appear that you can purchase the pre manufactured PCB anymore which isn't too much of an issue as is a simple circuit layout really so will just make my own up.

Thanks in advance!

[sbatesau]

Thanks so much for your story!  I'm stuck in a similar situation with an LXD75 that's died, and you can't get the parts anymore.  A lot of Googling eventually led me here, after a lot of options that cost more than the mount itself cost me.  This seems like a really  good option, and you've laid out very well how it all fits together.

[Michaelo]

A similar position here...

When cleaning my 497 handset the ribbon to the display disintegrated and there's no replacement display available. A new handset costs €140... ouch.

Looked for open source solution and found onstep and it costs much less than a commercial solution. I can also repair when necessary and update when new attachments arise. I may even repurpose the 497 handset enclosure and build a hand controller for the onstep for all for less than $20.

I'm currently collecting all the information and trying to decide on which Micro to use, now I have another reference to make my life easier, thanks for sharing Fish...

[astrosathya]

Hi,

Really well logged build. Please let me know what has been your experience in using it. I am building the CNCV3 Wemos version for my HEQ5-PRO whose board went bust a month ago