Search the Community
Showing results for tags 'alt az low budget build'.
Found 1 result
Here is some serious DIY stuff on a shoestring buget! This is a semi automated altaz I built from junk, literally. The eat/west axis drive is based on the worm gear set from an 80’s Ford pickup windshield wiper motor that had a locked up motor. I chopped off the motor part with my angle grinder, fit a 3/8” socket to the remaining 11mm shaft with JB Weld and ground a pre-mounted timing belt pulley on a small bipolar stepper motor to loosely fit the drive end of the socket. That is mounted to some diamond plate aluminum. The up/down segment is the guts from an old dead paper shredder. The original motor had burned out, but the mounting bracket fit the bolt pattern to another bipolar stepper I had. To couple the worm gear shaft, I again chopped the motor off and cut the remaing worm gear shaft to length, and then coupled that to the stepper shaft. I used some fairly rigid rubber fuel hose slightly smaller than the stepper shaft, which was slightly smaller than the worm gear shaft. I can detect no slipping with my C90 mounted so it seems to work. If I do get slipping a small hose clamp will be employed. I bought two high quality bearings locally for $15 to cradle the cross bar that actuates the final drive, and JB Welded those to the scrap aluminum plate left over from a barn door tracker I built last summer. I am going to use the Arduino Nano to send signals to two Easy Driver bipolar stepper motors for the two axis of movement. I bought two of those analog joysticks via eBay for $6. I have yet to write the code, but with web references I have a pretty good grip on that issue. I bought the Nano and Easy Driver clones from eBay for under $5 each, and got 6 each for WHEN I blow some up. I plan on using old phone coiled cable from the screw terminals, which are salvaged from an obsolete multi-line phone, to the steppers. This should give me plenty of slack and still carry the signals. A small plastic box will house the drive electronics. I have plans to switch the setup off when not actively pointing to both save power and keep the drivers/motors from building heat. As you can see the steppers and gear train hold my scope in position without power. This was actually the test undertaken for the photo. I plan on using the joystick switch to shift the Easy Drivers from full stepping down to 1/8 stepping, and hope to be able to slew quickly and then accurately center my target(s) with very fine movements. The windshield wiper gear ratio seems to be 58.6 to 1, while the paper shredder seems to be 45 to 1. I plan on powering the setup with a sealed lead/acid 12 volt battery I currently use to drive my barn door tracker. Eventually I plan on mounting this to the barn door (separate Ardunio Nano and Easy Driver) and use the battery for both. Besides writing and testing the code I still need to disassemble the gear drives, clean them well and lube them well with a synthetic grease. I may build a cover for the paper shredder gear train, but that isn’t high on the list. I am jazzed to get this finalized and working, and I am pretty confident the hard part is behind me.