Yet another project on my current list, or two….
Been building a CNC machine for a hardware project I’ll be working on with a friend. Currently a 3-axis machine controlled by LinuxCNC system, eventually it will accommodate a machining tool, a pick and place tool and an extruder (for 3D Printing). I’ll also be building an embedded stand-alone controller so it can operate independent of the computer.
It will machine parts for me.
it will print parts for me (like new gears for the telescope mount).
and it will build circuit boards for me!
Speaking of the telescope, yes it needs better gears, current ones were hacked together so its not smooth or linear enough for me, also I plan to re-do parts of the code to improve its handling.
I really have too much to do in my spare time, need to win the Lotto so I can work on them full-time… 😛
Anyways, here’s some pretty pictures of the machine until next update 😉
As requested here is the current source code for my Scope Tracker. It’s not clean but it works for me.
Two main files, – main.c & scopetrack.h – in this zip file
I’ll get some schematics up later
One important thing to note, the redlib library that is supplied for NXP Programming has a bad file that unless they’ve fixed it since WILL need to be fixed of this code wont work, basically there is a bad offset in the port mapping, I’ll see if I can track down the file I changed to fix it and add it to this post…
edit: Found the file: #include <NXP/LPC17xx/LPC17xx.h> I had to fix the offsets for FIO2 & FIO3 references (I think – check differences with your own version and change as needed)
Just been outside in the freeze taking some photos of tonight’s Lunar Eclipse. Only a Partial but still an event! Even gave the motorized mount a use for it!
Bit of cloud around fuzzing up the pics but still reasonable.
Thanks for reading!
Another long delay, but this time the telescope project has been totally remade.
All the framework has been machined out of Aluminum sheets making the unit much more rigid without being too heavy, plus re-sized to allow for a larger telescope in the future (the current 4.5″ mirror isn’t all that exciting… ). I’ve also used secondary gearing so I get more torque out of the motors as well as better accuracy – I now get 0.0018 degrees per step.
Electronics are based around the NXP LPCeXpresso dev board using an lpc1769 ARM processor. The NXP chip controls 3 separate motor circuits gated for 12V drivers ( Azimuth, Altitude and Focus) all timed off separate timers so each can be individually speed regulated. Communication with the PC is by a Bluetooth serial module and the board also drives a 132×132 pixel color LCDmodule to show tracking details. This chip runs at 120MHz and has plenty of speed to keep tracking and control as smooth as possible.
I’ve mostly programmed the NXP to emulate the SynScan AltAz GOTO mount commands as well as a few of my own custom for other work. This command set allows easy control via Stellarium software for field work.
This video shows the mount going from flat North to M48 then to the Moon via PC, then I click the Home button on the hand controller at the end.
This video is the same but from the software viewpoint.
Just need to weatherproof the electronics inside a box and add a stable mount. (then get a real telescope for it… )
Until next time!
Finally got around to ordering some better motors. Arrived this morning: 3 NEMA 23 type Steppers. 1.8deg per step 0.4A but more important is the power – 34N/cm. thats about 200 times stronger than the last lot and they feel it, very hard to stop.
So wired them with connectors and plugged into the Driver pcb. Tweaked the software and uploaded it. Made up some quick brackets to hold the motors to the mounts. Ran the tests. Absolutely perfect!
Movement is quite quick and accurate. Driver runs at 200 steps per second with a 1.8 deg motor and 50:1 gearing I get 10,000 steps to 360 degrees or 0.036 deg accuracy. Full 360 deg turn in 50 seconds.
Youtube video for visual show:
Cold, rainy and cloudy outside so no practical testing, still happy with the result though.
All I need to do now is tidy it up and weatherproof it a bit more.
Future changes will be to remake the whole mount out of metal (aluminium) instead of wood. Wood made it easy to chop and change but now it’s pretty set metal will give it more solid movement and better life (and look better 😉 )
Also intend on adding a Bluetooth module to remove the controller wire and to improve the MCU board. I have an NXP Arm proto board here I’d like to use. Gives me the ability to make it more responsive and featured.
Thats all for today.