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About fluidhomefront

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  1. If you get the option, Id recommend a Proxxon drill/grinder over a dremmel. The bearings are much better and the drill stands/presses are cheap but rock solid. I needed one to drill the many 0.8mm holes in a pcb and reading around put me off the dremils for that particular job.
  2. Nick, I think that sort of noise can make stripes on your final image. And, yes, its possible to remove the noise with fft of the image. I divide the image into lots of tiles (64x64 pixel squares say) and take ffts of every tile. I then find the median of all the fft tiles. Any bright spots in the median power spectra tells you the spatial frequency of the stripes and you can block that frequeny from the final image with more fft/ifft. It works very effectively and is better than most paint program 'destripe' algoritms.
  3. If you've got a spare io pin, you could add a little infra-red receiver . The ir receiver example code for the arduino is good. Ive got some code that does smooth acceleration/deceleration of the focus stepper using an ir remote if its of use?
  4. Hi kirk, Im still working on this at a rate of about 2-4hours a week. Ive got the first prototype board made now and have communication with the clocks , digital potentiometers and FT232 usb chip. All the voltage levels look good. Next week will start writing clock driving code. The overall board layout uses a full 160x100mm pcb but this is because Im trying out a lot of options on one board. Visible bugs include one of the opamps was a smaller package than I thought and I didnt have a 5.1v zener diode to hand but can get away with a 10v one instead It takes me about an hour to produce a pcb in the kitchen, another hour to drill it and insert track pins and another hour to populate.
  5. With my 8" f/6 mirror of 3/4" thickness, I epoxied three strong neodymium magnets to the mirror and three magnets to the cell. The magnets have slippy surfaces. I mounted the magnets at 0.6D. My thinking is that the thermal expansion of the mirror and elastic deformations just make the magnets slide over each other a little. The magnets are plenty strong enough to stop the mirror falling off though. By setting one pair of magnets to have the opposite orientation to the other two, the mirror can only be mounted one way round. I don't see any astigmatism in star tests and I can put the mirror away in a box after I finish observing. Collimation is unchanged each use.
  6. Thanks for the link Chris. Very interesting. It looks like they get some clean images. The schematics for prototype 1 of my Arduino Shield CCD are attached. I'm trying out a number of options on this board and so need more GPIOs than I intend to have on the final board. As such, I'm using the LeafLabs Maple to control it rather than an Arduino as it has an extra connector. I've had a busy September/October but now there are some rainy nights and free weekends available for project work. http://opencamera.wikispot.org/Schematics Any thoughts or comments are welcome, especially if they are pointing out blatant mistakes.
  7. and rigid set of tube rings. You can get away with a lot for an f/6 scale telescope. Aluminium can be bought from local metal suppliers or big online websites for surprisingly low cost.
  8. Anothet source of large light weight waterproof tubes are amateur rocketing suppliers. These guys compete to make their rockets go the highest so we can take a lateral step into their market. Kite suppliers are good for carbon truss components. I enjoyed trying out aluminium braising with a blow torch and special solder. It cost £70 for a torch and solder kit. I watched a couple of YouTube videos and a couple of weekends later I had a lihght
  9. Another thing to watch is 'ripple'. Computer PSUs might give some oscillation on the lines that could effect the image from a CCD camera say. 12v dc might actually be 12v but with a 0.1v voltage spike every few micro seconds. This could make stripes on a digital camera image.
  10. Another thing to watch is 'ripple current'. Computer PSUs might give some oscillation on the lines that could effect the image from a CCD camera say.
  11. pixueto,Have you tried applying some solder flux to the joint to help the solder flow more freely? A water soluble flux pen costs just a few pounds. It can also help to actually apply more fresh solder to a joint before desoldering for similar reasons.
  12. I think embedded linux is not naturally a real time operating system. You can force toward low latency but its not really designed for that. No good for driving clocks then
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