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Vixen DD-1 guide port?

Posted: Fri Dec 14, 2007 1:11 am
by kauzuak
I've seen hits and tips about adding a guide port to the DD-1. Doug's write(s) up in the shoestring download section probabaly has the info, but I guess I'm not smart enough to put it all together. I'm still missing something. How hard is it to do it, and is there a good guide on the web?

Posted: Fri Dec 14, 2007 6:07 pm
by dpanderson
We have had several customers successfully modify the DD1 handcontroller. It is very similar to the instruction for the EQ handcontroller given in:
http://store.shoestringastronomy.com/eq_mod.pdf

We even had one customer send us a nice photo of where they soldered in the wires on the DD1. It can be seen at:
http://store.shoestringastronomy.com/images/DD1.jpg

Because of the logic used in the DD1, you will need our GPUSB-AH product to work properly with it. The GPUSB will not work.

Posted: Sat Dec 15, 2007 8:46 pm
by kauzuak
Doug,

Thanks for the links. So, a modified DD-1 isn't compatible with an ST4 output from a dedicated autoguider?


Kevin

Posted: Sun Dec 16, 2007 9:02 am
by dpanderson
I think it would be if the autoguider used relays, but not if it used optocouplers like our GPUSB and GPUSB-AH do.

By adding relays internal to the handcontroller, as shown in schematic GP1 of this document:
http://store.shoestringastronomy.com/do ... idance.pdf
then it would be compatible with our GPUSB and most dedicated autoguiders.

Re: Vixen DD-1 guide port?

Posted: Thu Nov 20, 2008 9:17 am
by astrophil
Hi,

Is it absolutely necessary to use a relay with a diode as described in: http://store.shoestringastronomy.com/do ... idance.pdf for the GP-1 schema?

I am trying to get a QHY5 drive a modified DD-1 controller.

thx

Philipp

Re: Vixen DD-1 guide port?

Posted: Thu Nov 20, 2008 9:33 am
by dpanderson
It is always good practice to have a reversed-biased diode across the coil of a relay. This helps to absorb inductive voltage spikes that occur when the relay coil is de-energized. If you don't have a relay with a built-in diode, you can always add a separate diode externally.

Re: Vixen DD-1 guide port?

Posted: Fri Nov 21, 2008 2:49 am
by astrophil
Hi Doug!

thanks for the quick answer, as I am electronically challenged, every advice is welcome!

with best regards,

Philipp

Re: Vixen DD-1 guide port?

Posted: Wed Feb 18, 2009 8:25 pm
by kcross
Hi Doug,

I thought I'd post my question, well it's really more of a clarification, here because the topic is relavant to my question. I recently wired my DD-1 to be used with the GPUSB-AH. However, I have an ST-8E to use on occasion, and I would like to be able to access both chips. If I were to do the GP1 relay modification, on a seperate hand controller if necessary or the same if possible, would I be able to connect the DD-1 directly to the ST-4 output on the camera so as I can use both chips? Thanks for your help.

Re: Vixen DD-1 guide port?

Posted: Wed Feb 18, 2009 11:42 pm
by dpanderson
I'm not an ST-8E expert, but I believe that would be true. If you did the GP1 relay mod, then you would need our GPUSB, not the GPUSB-AH. We would take your GPUSB-AH back in exchange for a GPUSB if you would like to.