GPS DIY for Celestron CG5 ????

[Sotein]

Hello everyone

I been loooking for some discussion over this but found nothing

Theres is anyway to connect a Non-Celestron GPS to the CG5 ??

Any adaptor??

I dont want to buy the original GPS

[Sotein]

I think that silence means theres no solution for this hehehe. Thanks anyway

[perfrej]

A gps is a gps. If you know the pinout and which NMEA sentences the mount wants it is simple task to build an adapter and make it work. Any info?

/per

[Sotein]

No ona have those pinouts and NMEA sentences??

[Deimosian]

I want in on this too! 

I have an AVX mount. At least for Celestron the pinout of their gps module would be the same nomatter what mount it goes to. Then maybe the pinout is not brand spesiffic either? 

Putting it all together, I guess you would need a micro controller like the arduino mini, and inexpensive GNSS receiver and antenna, and a cable to fit in the AUX port. (The AUX ports provide power as far as i know) So not more than $50 US?

Not to be a bummer, but lets do a reality check. Can you justify the necessity to spend time and money on a project like this? Or the $200 for the actual SkySync GPS accessory?

I want to argue that the 'time' information from the GNSS system would help the most, because I tend to see the mount's RTC drift a lot over the months, and its a pain in the ass to correct it. But for position I'm not convinced. Having a rough position, knowing the time, and doing a two star alignment. I believe the mount calculates a specific rotational matrix for each time an alignment is done. After all, the mount and controller is basically a giant sextant with a huge catalog attached to it.

Can't I use the clock from my computer somehow? It's a lot easier to update. 

PS. Sorry if I crushed anyone's hopes and dreams... I'd love to make this thing myself. 

[Pat Warborg]

I was thinking about this, too! NMEA is a standard. I can't believe that mount vendors are going to program their own interfaces for a GPS. The most simple way I can come up with to make their GPS proprietary would be to use an arbitrary wiring of their connectors. There should not be much more than +5V, ground, Tx and Rx, though. Is there anybody around here with experience to tell how to find out about this?

Pat

[brown_rb]

Have a look here for a DIY gps arduino based

https://sourceforge.net/projects/arduino-gps/

[Pat Warborg]

13 hours ago, brown_rb said:

Have a look here for a DIY gps arduino based

https://sourceforge.net/projects/arduino-gps/

Thanks! That's an interesting project. Impressive what DIYers are up to these days. :-)

If now somebody would know the pin layout of the Celestron GPS, one could try and see if the mount (hc) does listen to NMEA via the AUX port...

Pat

[Pat Warborg]

I found an interesting link: http://www.stargps.ca/

Might be interesting for people looking into GPS capability addition to their rigs. Seems less expensive than the vendor's GPSs (especially in the case of Celestron). They also provide information on how to connect any existing GPS to various mounts!

I would like to add a GPS to my Starsense for Skywatcher setup, because I'm tired of punshing in date and time on every start up. Not that tired though, that I would readily spend more than 200€ just for that... :-)

I did some tests last night with the redirect.exe I downloaded from stargps. Seems that indeed I can just redirect the NMEA input from my cheap amazon GPS (I still had around) to another UBS port. So far, I couldn't bring it to talk to the Starsense hc which was connected to another USB port. The website claims it should work that way. I guess I need to spend some more time on this.

Any input from anybody who tried this before is very much appreciated! I probably will start another thread with this concrete question...

Thanks,

Pat

[Pat Warborg]

On 1.9.2014 at 17:11, perfrej said:

A gps is a gps. If you know the pinout and which NMEA sentences the mount wants it is simple task to build an adapter and make it work. Any info?

/per

That's what I thought in the first place. But then on the stargps website they are talking about their GPS being compatible with NMEA as well as various vendor protocols...  Maybe it's not that simple after all... I'm surprised that nobody seems to have tried this before!

Thanks,

Pat