It is currently Tue Aug 14, 2018 8:40 am

All times are UTC




Post new topic Reply to topic  [ 7 posts ] 
Author Message
 Post subject: remote focuser for mak 127
PostPosted: Mon Dec 31, 2012 3:23 pm 
Offline
Member

Joined: Thu Jun 14, 2012 5:46 pm
Posts: 99
Location: Little Lever
I'm in the process of making a remote control focuser for my mak 127 using a rc car Tx contoller.I have a wired focuser which I made with a 10 meter cable and it seems ok just need to get better potentiometer. Thought I would try to make one wireless so there's no need of all the wires. Has anyone tried this method and does it work?


Top
 Profile  
 
 Post subject: Re: remote focuser for mak 127
PostPosted: Tue Jan 01, 2013 11:26 am 
Offline
Member
User avatar

Joined: Mon Oct 12, 2009 6:47 pm
Posts: 1255
Location: Bolton
I don't see any advantage in making it wireless John: I just have a short 1.5m lead on mine (for use when observing at the 'scope) and then an 8m extension-lead which I can plug in for remote control (when I'm imaging from indoors) - and then it's just one of three or four cables which are fed in through the window (the others are for mount control, imaging camera and guide-camera).

In my case, the sole power supply (a 9V battery) is in the hand-control, whereas for a wireless remote you'd need two separate DC supplies: one for the motor/receiver and one for the hand-control/transmitter.

Try to minimise the extra weight your focusser adds to the back of your optical tube - there are some lovely little DC motors which run at a few RPM available for under £7 from China via eBay:
http://www.ebay.co.uk/itm/6V-DC-8RPM-Powerful-High-Torque-Gear-Box-Motor-/320959748509
http://www.ebay.co.uk/itm/12V-DC-8RPM-Powerful-High-Torque-Gear-Box-Motor-/330755869665
then you just need a hand-held battery-box fitted with a reversing on/off switch, and maybe a switchable series resistor for extra-slow speed.


Top
 Profile  
 
 Post subject: Re: remote focuser
PostPosted: Tue Jan 01, 2013 11:51 am 
Offline
Member
User avatar

Joined: Mon Oct 12, 2009 6:47 pm
Posts: 1255
Location: Bolton
rwilkinson wrote:
there are some lovely little DC motors which run at a few RPM available for under £7

Or if you can make a worm-and-wheel drive for your focusser, then one of these ultra-light 30RPM motors will do the job:
http://www.ebay.co.uk/itm/30-RPM-DC-6V-2-5KG-Micro-Gear-Box-Speed-Reducing-Motor-/380531501031
Attachment:
mk1_dean.JPG
mk1_dean.JPG [ 128.23 KiB | Viewed 5255 times ]


Top
 Profile  
 
 Post subject: Re: remote focuser for mak 127
PostPosted: Tue Jan 01, 2013 4:30 pm 
Offline
Member

Joined: Thu Jun 14, 2012 5:46 pm
Posts: 99
Location: Little Lever
Attachment:
P1010142.JPG
P1010142.JPG [ 150 KiB | Viewed 5246 times ]

I bought this bracket off ebay £16. the guy was doing the full focuser set up for £48 so i emailed if he could do just the bracket and bought the other bits and pieces from maplins and the foam wheel on the focuser knob from a rc shop in Blackburn. The rc stuff i already had from a old car which i've robbed some of the parts off..For the wired focuser I fitted the modified servo where the 3 holes are on the bracket, to do the wireless one I have to remove the servo and fit it into a box [100x75x40] with receiver and battery pack and fit the box on top of the bracket. If it works ok I will saw off the handle on the TX and where the batteries are fitted in the base of the handle I will velcro them to the back of the Tx as its a flat pack thats just to make it a lot smaller.


Attachments:
P1010145.JPG
P1010145.JPG [ 147.5 KiB | Viewed 5246 times ]
P1010146.JPG
P1010146.JPG [ 158.5 KiB | Viewed 5246 times ]
Top
 Profile  
 
 Post subject: Re: remote focuser for mak 127
PostPosted: Tue Jan 01, 2013 4:36 pm 
Offline
Member

Joined: Thu Jun 14, 2012 5:46 pm
Posts: 99
Location: Little Lever
Just want to eliminate all the wires, I learnt my first lesson when veiwing to rap up well when in sub zero temperatures., I just getting over a bad dose of flu and cough :roll: So from now on i'll be sat inside and doing it


Attachments:
P1010147.JPG
P1010147.JPG [ 146 KiB | Viewed 5246 times ]
Top
 Profile  
 
 Post subject: Re: remote focuser for mak 127
PostPosted: Thu Jan 03, 2013 5:20 pm 
Offline
Member

Joined: Thu Jun 14, 2012 5:46 pm
Posts: 99
Location: Little Lever
Job failed.After modifying the servo cogs inside the servo for 360 degree rotation it looks like the tx sends a constant signal to the receiver so the motor runs all the time in one direction,inside the servo as well as the circuit board there is also a potentiometer linked to the cogs and circuit board i disconnected this hoping it would stop the signal but that didnt work...so its back to the wired version :(


Top
 Profile  
 
 Post subject: Re: remote focuser for mak 127
PostPosted: Mon Jan 14, 2013 7:51 pm 
Offline
Member

Joined: Thu Jun 14, 2012 5:46 pm
Posts: 99
Location: Little Lever
news update..I've managed to get it working, and up to now it seems ok.I tried it the other night on Jupiter and it was great, no more waiting for the scope to settle down after touching the focuser. just testing now how long the rechargable batteries will last with it switched on all the time. what i have to do now is fit a charging plug to the transmitter so i dont have to remove batteries to charge them. On the receiver box i fitted a on/off switch with a charging socket..

PS..I would like to bring it along tomorrow night as I need someone to show me how they setup the Go To.. as I'm having problems with this....if thats ok


Attachments:
P1010152.JPG
P1010152.JPG [ 151.5 KiB | Viewed 5180 times ]
P1010151.JPG
P1010151.JPG [ 148.5 KiB | Viewed 5180 times ]
P1010148.JPG
P1010148.JPG [ 164.5 KiB | Viewed 5180 times ]
Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 7 posts ] 

All times are UTC


Who is online

Users browsing this forum: No registered users and 3 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group