author
12Instructables204,660Views217CommentsIowa, USAJoined May 3rd, 2010
I'm an aerospace engineer by trade but am interested in astronomy, robotics, CNC machines, Arduinos, you name it.

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  • Portable Low Cost DIY Solar Panel Setup

    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/id/Mobile-Solar...

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    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/id/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

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  • Portable Low Cost DIY Solar Panel Setup

    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!

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  • maewert commented on ksimmons44's instructable The Necronomicon3 months ago
    The Necronomicon

    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!

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  • maewert's instructable Color Changing Crystal Staff for Cosplay's weekly stats: 3 months ago
    • Color Changing Crystal Staff for Cosplay
      331 views
      23 favorites
      3 comments
  • 600 Watt, 3d-printed, Halbach Array, Brushless DC Electric Motor

    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

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  • maewert followed zaphodd423 months ago
      • Make PVC Look Like Wood
      • Instamorph and Oogoo, Together at Last.
      • Stained Glass Moravian Star Ornament
  • maewert commented on maewert's instructable Color Changing Crystal Staff for Cosplay3 months ago
    Color Changing Crystal Staff for Cosplay

    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!

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  • maewert made the instructable Make PVC Look Like Wood3 months ago
    Make PVC Look Like Wood

    I used this technique to create my color changing cosplay staff featured here: https://www.instructables.com/id/Color-Changing-Crystal-Staff-for-Cosplay/Thanks for the instructable!

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  • maewert commented on Markwrig's instructable PiKon Telescope4 months ago
    PiKon Telescope

    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!

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  • maewert commented on maewert's instructable Gray Codes4 months ago
    Gray Codes

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

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  • maewert commented on tomatoskins's instructable Custom Tool Wall4 months ago
    Custom Tool Wall

    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

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  • Internet Connected Story Book (Featuring Particle Photon)

    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!

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  • maewert commented on maewert's instructable Optical Testing of Parabolic Mirrors6 months ago
    Optical Testing of Parabolic Mirrors

    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.

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  • maewert commented on tittiamo68's instructable Clock Set Date Time6 months ago
    Clock Set Date Time

    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.

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  • maewert commented on alexb369's instructable How to:2 button 2 different led sequences7 months ago
    How to:2 button 2 different led sequences

    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!

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  • Internet Connected Story Book (Featuring Particle Photon)

    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.

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  • maewert commented on gigafide's instructable How To Make A Raspberry Pi SuperComputer!7 months ago
    How To Make A Raspberry Pi SuperComputer!

    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.

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  • maewert's instructable Advent Calendar Box's weekly stats: 8 months ago
    • Advent Calendar Box
      284 views
      6 favorites
      3 comments
  • maewert commented on maewert's instructable Advent Calendar Box8 months ago
    Advent Calendar Box

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

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  • maewert commented on keebie81's instructable Binary Game9 months ago
    Binary Game

    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

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  • maewert commented on madcow120's instructable Solar Power Bucket10 months ago
    Solar Power Bucket

    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/id/Mobile-Solar-Power-Station/

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  • maewert commented on alinke's instructable The DIY Photobooth with Lighting Control10 months ago
    The DIY Photobooth with Lighting Control

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

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  • maewert commented on maewert's instructable Mobile Solar Power Station10 months ago
    Mobile Solar Power Station

    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!

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  • maewert commented on madcow120's instructable Solar Power Bucket10 months ago
    Solar Power Bucket

    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!

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  • maewert commented on maewert's instructable Interfacing Electronic Circuits to Arduinos11 months ago
    Interfacing Electronic Circuits to Arduinos

    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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  • maewert commented on maewert's instructable Internet Island11 months ago
    Internet Island

    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!

    Yes! visit https://racheloffline.org/

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  • maewert commented on MertArduino's instructable Arduino: How To Play Guitar with Arduino12 months ago
    Arduino: How To Play Guitar with Arduino

    Nice start!According to the Axis of Awesome you will need 4 chords to play any pop song ;-). So just a little more work and you can play them all!Best Wishes.

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  • maewert commented on hasenbaby's instructable Arduino Device With Zero Standby Power1 year ago
    Arduino Device With Zero Standby Power

    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

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  • How to Unlock Your Car in 30 Seconds

    Maybe it is not his car!

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  • maewert commented on goldfishrock's instructable Shed 12v Solar Lighting System1 year ago
    Shed 12v Solar Lighting System

    Very nice instructable!I made mine on my van here (https://www.instructables.com/id/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 anoth...

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    Very nice instructable!I made mine on my van here (https://www.instructables.com/id/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!

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