hello guys this is my first post and i have never build a circuit before.

im building a barn door tracker, so i can take astrophotography.

im following instructions found in this website http://www.garyseronik.com/?q=node/52 the instructions are at the bottom.

i was wondering is there a way i can change the power supply to 12v instead of 9v? and how would the new circuit look like?

thanks in advance

 

This will work on 12V with no problem as it is rated for up to 35V + output voltage.
Just make sure you are using the LM317T version with a good heat sink as it will dissipate 50% more heat at 12V

 

i couldnt find the 500 ohm multiturn potentiometer is there a way i can use something else?

 

Digikey has multiturn pots, something similar to this one might work.

 

If you don't have multiturn pots you could put 2 regular pots in series, say 1000 ohm and 100 ohm. One for course adjustment and the other for fine adjustment.

pilko