maewert

Thank You for the very informative Instructible! I enjoy seeing others building telescopes!

No, shorting the A and B lines should not permanently damage the device, just cause the bus to not function while shorted.

Jacob, You should be able to use an inverter to convert the nominal car battery voltage to 110v AC required by the MavicAir AC Power Adapter. Looking at the specs (https://www.dji.com/mavic-air/info) I believe the AC Power Adapter requires 60 watts continuous power so size your inverter to provide at least double this current (and size your cables from the battery to the inverter to take the current!). If we expect 80% efficiency that's over 6.25 amps from the battery nominal, not including inrush spikes. If your inverter is complaining then you may have too small/too long wires between battery and inverter and hence a voltage drop. I also don't know if the AC Power Adapter is fine with a modified square wave or if it requires a pure sine wave inverter... that could also be your probl…

Jacob, You should be able to use an inverter to convert the nominal car battery voltage to 110v AC required by the MavicAir AC Power Adapter. Looking at the specs (https://www.dji.com/mavic-air/info) I believe the AC Power Adapter requires 60 watts continuous power so size your inverter to provide at least double this current (and size your cables from the battery to the inverter to take the current!). If we expect 80% efficiency that's over 6.25 amps from the battery nominal, not including inrush spikes. If your inverter is complaining then you may have too small/too long wires between battery and inverter and hence a voltage drop. I also don't know if the AC Power Adapter is fine with a modified square wave or if it requires a pure sine wave inverter... that could also be your problem. You could go with a 24 volt system as you suggest using two car batteries and a 24 volt inverter. Increasing voltage is much easier on the electronics since the resistive losses are proportional to the square of the current.If I were you I'd stay away from any electronic project to make 14.4 volt boosters, etc. and stay with consumer products. Boosting the battery voltage artificially would probably only end up draining the car battery below its 50% line and significantly reducing its life. Best Wishes

Mine is one heavy beast. My panels are 4 foot by 4 foot and double hinged as you noted. When opened fully it takes up more than 16 feet of wall space. I made mine close for safety since I had young kids at the time.Thanks again for the nice Instructible!

When laminating layers of plywood to construct the ground board, it is important to only use Astronomy book as weights. I see in your photo that you allowed a few physics books in the stack ;-) I suppose with the beauty of your build we can forgive you.Seriously though, a well made machine and well written 'ible! Dobs are perfect for manual observation with large primary mirrors. The full thickness 10" mirror I ground and polished needed a Dob to take the weight and provided the buttery-smooth movements that feel so good making it a joy to use. (Except at the zenith....grumble, grumble.)I later purchased a Celestron C14 on a german eq mount, which breaks down to small enough pieces that I am still able to man-handle solo when observing in the field. Your Dob should be able to …

When laminating layers of plywood to construct the ground board, it is important to only use Astronomy book as weights. I see in your photo that you allowed a few physics books in the stack ;-) I suppose with the beauty of your build we can forgive you.Seriously though, a well made machine and well written 'ible! Dobs are perfect for manual observation with large primary mirrors. The full thickness 10" mirror I ground and polished needed a Dob to take the weight and provided the buttery-smooth movements that feel so good making it a joy to use. (Except at the zenith....grumble, grumble.)I later purchased a Celestron C14 on a german eq mount, which breaks down to small enough pieces that I am still able to man-handle solo when observing in the field. Your Dob should be able to break down into pieces as well should you ever take it places, however, what I can see of your viewing location it appears to be a good site. You are going to pour a pad, yes? Maybe give it a home so you don't have to wheel it far? If so, please post the updated observatory pics!Thanks and Best Wishes!

So Cool!

Nice Update there!

Have you seen these examples? https://www.instructables.com/Making-a-Beefy-Pe...https://www.instructables.com/My-Diy-Peltier-Co...https://www.instructables.com/DIY-Peltier-Bever...Best Wishes

This is a nice build. I like these clocks. I note that you never illuminate the "O'CLOCK" nor the "MINUTES". MINUTES would be easy but you'd have to change the 'R' character to an apostrophe in your mask if you wanted to show O'CLOCK. Also if you moved 'HALF' over to the right one space you could use the unused 0,2 position to show 'A' so you could say "IT IS A QUARTER TO ONE" instead of the less grammatically correct "IT IS QUARTER TO ONE".Just some thoughts.Best Wishes!

During the rough grinding process you are simply trying to 'hog' out the glass to get the rough figure close to the desired focal point. Here we can use the 'spit test' which uses the foucault tester to simply measure the focal point of the majority of the mirror and then you spit on the ground, i.e. you mark the focal point very roughly to ensure you're deep enough to begin the next phase. After hogging out the mirror then you use finner and finner grinding grits to remove the scratches in the mirror from the previous step. During this phase you are averaging out your strokes to keep the mirror figure roughly spherical. As soon as you transition to polishing is where I begin to take real measurements and good records. Each person's hand pressure is different so you must 'learn' how …

During the rough grinding process you are simply trying to 'hog' out the glass to get the rough figure close to the desired focal point. Here we can use the 'spit test' which uses the foucault tester to simply measure the focal point of the majority of the mirror and then you spit on the ground, i.e. you mark the focal point very roughly to ensure you're deep enough to begin the next phase. After hogging out the mirror then you use finner and finner grinding grits to remove the scratches in the mirror from the previous step. During this phase you are averaging out your strokes to keep the mirror figure roughly spherical. As soon as you transition to polishing is where I begin to take real measurements and good records. Each person's hand pressure is different so you must 'learn' how your particular strokes are changing the mirror figure while polishing. Books may guide you but you can't rely on them blindly due to this variance in each person's polishing strokes. You may find that in order to reduce the 3/4 diameter ''ring' you have to do some funny 'W' stroke where the center up-down stroke is smaller than the outer legs. Essentially you record what your strokes do to the mirror figure and you use that knowledge to move the figure closer to the ideal. Be sure to allow the mirror to cool as the polishing strokes can heat the surface, changing it so that it tests well right after the strokes but then get out of figure after the mirror cools.During the polishing phase it is a contest between how much polishing you can stand against your desired level of perfection. I recall 'fondly' of doing one more little polish to make the mirror a little better and making the mirror worse only to have several hours of work to bring it back to its original level of 'goodness'. :-)The feeling is great when you finally call it Done.Best Wishes!

Nice 'ible. Have you had any experience in printing worm gears instead? I didn't see any mention of whether there was considerable backlash when changing focusing directions. If backlash is a problem then maybe using worm gears would resolve the issue. Just a thought.Best Wishes.

The panel I'm using is 'only' 280 watts which is still pretty good for a minivan but much smaller than your number :-). (The wattage stays the same when converting the voltage from 48 volts to 12 volts, it's the amperage that increases by 4) Even at 280 watts it should be able to run a mini fridge. (Of course you'd want to modify the van so the hot air from the fridge could escape out of the vehicle...)Calculations: Assuming 4 hours of sunlight/day * 280 watts gives us 409 KWh per year and a mini fridge takes about 265 KWh per year, so my system has a good margin for losses looking only at the solar side.Next you'd have to calculate whether I have enough battery storage to keep the fridge running during the expected nights and cloudy days. Mostly depends on where you use it so I'll le…

The panel I'm using is 'only' 280 watts which is still pretty good for a minivan but much smaller than your number :-). (The wattage stays the same when converting the voltage from 48 volts to 12 volts, it's the amperage that increases by 4) Even at 280 watts it should be able to run a mini fridge. (Of course you'd want to modify the van so the hot air from the fridge could escape out of the vehicle...)Calculations: Assuming 4 hours of sunlight/day * 280 watts gives us 409 KWh per year and a mini fridge takes about 265 KWh per year, so my system has a good margin for losses looking only at the solar side.Next you'd have to calculate whether I have enough battery storage to keep the fridge running during the expected nights and cloudy days. Mostly depends on where you use it so I'll leave that calculation to you if you really need to know.For me I just wanted enough power to run my Celestron 14 inch scope (and accessories) through the night.Best Wishes!

Clearly the smaller the error the better. I said the error has to be less than 1/4 wavelength and thereby set an upper bound to the figure error. Defining the 'best value' was not the purpose of the instructable.Best Wishes

I'm very glad that your cabin had survived 6 years of heavy snow loads without failing! I am also happy that I and others shared our concerns over the roof design and offered ways of correcting the roof if needed... but am very glad it hasn't been needed in your case!Best Wishes

Your request is 9 months old, I know, but I think the best place to look (I've found so far) is the Passive House or the Net Zero house design plans/goals. Canadian goals I believe are to go this route by 2030 so they appear to be the US's closest neighbor leading the effort. I'm thinking about such a retirement 'cabin' so I have 0 monthly expenses to stretch my retirement $$s. Simple idea is to essentially build two walls, one inner and one outer minimizing any connecting material between the walls. R60 walls and R100+ roof, good energy recovery system to exchange air, oh, and VERY good windows and doors. Extremely air tight to the point of worrying about air leaking between the floor and sill plates, etc. Best Wishes.

Very Nice! For your next upgrade ditch the screen by adding color LED buttons that you use to flash the pattern and maybe a buzzer and an on-off switch to let the bear run without being tethered. Best Wishes

Thanks!

I've seen pictures of beautiful work spaces like this one. Don't think I ever owned one... at least for more than a few minutes.Nice work!

I just used math to estimate that at best if your inverter is supplying its maximum 400 watts, then the draw on your 12v battery should be 33.3 amps (P=IV). Usually the inverter is maybe 90% efficient (or less) so the real current would be even higher. If you try to draw more current than 10 amps, hopefully the charge controller won't fry but will simply limit to 10 amps... and the inverter maybe will beep a warning or at least indicate on its LEDs that the source is insufficient.You can measure the current draw on the battery with a multimeter but most can only measure up to 10 Amps or less. Here is one link on how you can measure higher currents using a shunt: https://mycontraption.com/measuring-current-withou...(On my system on my van (https://www.instructables.com/Mobile-Solar-Powe…

I just used math to estimate that at best if your inverter is supplying its maximum 400 watts, then the draw on your 12v battery should be 33.3 amps (P=IV). Usually the inverter is maybe 90% efficient (or less) so the real current would be even higher. If you try to draw more current than 10 amps, hopefully the charge controller won't fry but will simply limit to 10 amps... and the inverter maybe will beep a warning or at least indicate on its LEDs that the source is insufficient.You can measure the current draw on the battery with a multimeter but most can only measure up to 10 Amps or less. Here is one link on how you can measure higher currents using a shunt: https://mycontraption.com/measuring-current-withou...(On my system on my van (https://www.instructables.com/Mobile-Solar-Powe..., I wired my inverter directly to the battery but doing this you lose the nice battery protection functions that the controller provides like disconnecting the load if the battery gets too low.)Best Wishes

Very nice! Is your Charge Controller too small for your inverter? The CMP12 has a 10 amp maximum current and a 400 watt inverter would draw as much as 33 amps, wouldn't it? I think you'll be fine if you keep the inverter draw less than 120 watts.Best Wishes!

The finished product sure is beautiful. I see some issues with the code (this happens to me too). Sometimes some of the code characters get garbled when you post them. The IF block for example lost some characters:...//Beginning of proximity tripif (cm{...Also I am unsure what the three servos are doing. Are all three servos used to open/close the book? I see you have LEDs as well, are they illuminating the eyes somehow? Maybe I missed these in your instructions. I could not get your movie to download correctly.Very nice book. I'll have to try making one myself!

Very nice!

Beautiful work. I would love to see this adapted to build generators suited for wind turbines.Best Wishes

I am not skilled in generator design. For wind applications I understand that low RPM generators are usually used to eliminate mechanical losses so that the generator is directly driven by the windmill. I'm also under the impression that generator startup force is important which may be due to the generator's cogging forces which would be multiplied also by any gearing if used. To use this motor as a generator without modification I believe would require maybe 50:1 mechanical gearing in order to provide 6k RPMs or so. Is it possible to optimize the design for low RPM?Thanks

Thanks. I spoke with someone at the convention who asked if I had grown the crystal myself. I hadn't. Apparently it is possible, though when I was looking for DIY crystals I didn't find anything that had the look I was hoping for, so I purchased the stone. The PVC wood stain I used seems to be holding up to fairly well, although I now notice a few tiny dings in the 'wood' probably from hitting it accidentally as I walked around with it. A sealer coat probably should have been used. Thanks again for your instructible!

Beautifully done! I've wanted to do this myself on SCTs. Now with the Pi Zero having wifi and a small cross section, you might be able to move the PI behind the camera. Run power down two of the spider legs. Would also be neat if the pi could auto-focus by moving the focus mechanism and motor into the spider stack as well. Well, these ideas might be better for a larger aperture scope that would require a 2 inch diagonal or so to give you some working room for the mechanics! Keep up the good work!

I corrected the code and attached it as a file instead to ensure it doesn't get mangled.Thanks!

I'll have to try this once I'm finished purchasing tools so I can lay them all out in a nice order... oh wait... I'm never finished buying tools so I'll never get to do this... :-(Nice 'ible! Thanks

I love the Push Here button. Just as you say, now you have lots of thinking to integrate the button into the story.Nicely done!

I implemented my knife edge by drilling a hole into the support 'stick' just large enough for the lamp to sit inside. I then glued one blade of a straight utility blade over the hole so it cuts the center of the light. I then added magnets above and below the light that would stick to the first and second blades allowing them to be adjusted.

Nice Instructible. I suggest eliminating the pull-down resistors on the buttons and use the arduino's internal pull-up resistors instead to reduce parts. Just change the logic and wiring so you get a ground when the button is pressed.Best Wishes.

Very nice instructable. By the way, the Arduino inputs have internal pull up resistors that you can turn on so that you can eliminate the 10K resistors. Here is a link that explains a lot about them: https://www.baldengineer.com/arduino-internal-pull...Best Wishes!

Beautiful work! I wonder for younger readers if you could activate each page by touching an exposed copper pad instead of using QR codes. Very nicely done. Thanks for sharing.

1. Pi Zero does not have built-in Ethernet, so no, this method is not suited to Pi Zeros. (There may be other methods tho that are suitable to Pi Zeros)2. No, once the super computer is setup you can run the programs on the cluster with no internet connection.

:-). Unfortunately I mailed one of the boxes I made this year so I can't guarantee they won't open ahead!

Very nice instructible. (I didn't find the code for the project, I must have missed it.)Another variation would be to display the user's selections in binary, hex, and decimal useful for teaching binary number system. Another variation may be to see if someone could sequence through all combinations without repeats by switching only one switch at a time ( i.e. a grey code).Just for fun I sketched out a similar circuit using discrete components which really shows why using a microcontroller can replace lots of discrete chips and is more flexible should your requirements change!.Best Wishes

I added a 285 watt solar panel to my van with two 6v golf cart batteries to power my Celestron CGE14 telescope. Similar purpose just different choices in the build details. https://www.instructables.com/Mobile-Solar-Power-Station/

Mine used the 'booth' part almost exactly like this instructable. The electronics were more like the electronics of https://www.instructables.com/Raspberry-Pi-photo...Best Wishes

1. You have a hearse. Cool. Hope it is empty.2. What do you currently do with the power you generate? 75 watts could run a fan to cool the back but air conditioners suck too much juice (like 115 v 11 amp with unknown surge) Best Wishes!

Nice instructable! I love to see solar projects done well. I do not believe, however, that your single EverStart UH1 battery is providing anything near 220 AH. I believe they have a reserve capacity of 30, making them more like 20 or less AH. I'm also not sure how well they perform when deeply discharged. They are a good quality battery for the money, though, just maybe not designed for deep discharge applications.Best Wishes!

Sorry to have missed your question until now. I have no direct knowledge of ARINC 568 (It isn't even available at the ARINC store. Is it very old?). Many of the ARINC standards describe the protocols that are sent over ARINC 429 data bus. If so, then yes. If Arinc 568 is a different data bus then no, it wouldn't.Best Wishes.

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Thank you. Unfortunately I reused the parts for other projects so I am currently susceptible to an EMP :-(. I'll have to get this system back in the stowed configuration just to be ready!

Nice instructible.Your circuit was a little difficult to follow, however. I would have labeled +15v as BATTERY and the +12V as something else such as SWITCHED_BATTERY. As shown it implies that you have several voltage levels and that you connect +15v to +12v.The purpose of Relay #2 is to switch off the power under the command of the microcontroller after it has been turned on via SW3. Wouldn't it be better to power Relay #2 coil from +12V instead of +15V? That way the relay 2 circuitry is powered only after the +12V is enabled thus ensuring it draws no power when not enabled.Best Wishes.

If you are willing to give up on the SW3 monitor and want to take it one step further and remove all high impedance de-energized paths, I think this would also work.Best WIshes

Maybe it is not his car!

Very nice instructable!I made mine on my van here (https://www.instructables.com/Mobile-Solar-Power..., also to be used for camping/astronomy. Lead acid batteries can out gas hydrogen when charging so be sure the vent them properly!Is the battery a deep cycle? You might want a deep cycle battery or you'll want to discharge it only a little bit to give the battery a long life.Back of the napkin calculations: If you want only 50% discharge on your battery then each night you will use at most 17 amp hours. Your 100 watt outputs say 7 amp hours in full sunlight and therefore should replenish the energy used in maybe 3 hours of sunlight. Looks like a good fit for low, winter sun. You'll produce more energy than you can store in the other seasons. You may want to consider adding another ba…

Very nice instructable!I made mine on my van here (https://www.instructables.com/Mobile-Solar-Power..., also to be used for camping/astronomy. Lead acid batteries can out gas hydrogen when charging so be sure the vent them properly!Is the battery a deep cycle? You might want a deep cycle battery or you'll want to discharge it only a little bit to give the battery a long life.Back of the napkin calculations: If you want only 50% discharge on your battery then each night you will use at most 17 amp hours. Your 100 watt outputs say 7 amp hours in full sunlight and therefore should replenish the energy used in maybe 3 hours of sunlight. Looks like a good fit for low, winter sun. You'll produce more energy than you can store in the other seasons. You may want to consider adding another battery when your pocketbook can take it to be sure you can continue to have lights after three cloudy days.Again, it was a very nice instructable!Thanks!