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dresch

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    • PicoPi LCD Using Arduino/Bodmer Library
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  • Arbitrary Wave Generator With the Raspberry Pi Pico

    Great, hope the op-amp circuit works for you also. It being a dual, if you end up implementing a dual channel AWG version, you have a second amp to build on.The amp circuit uses a resister divider to impart a slight offset which centers the inverted amplify. Thanks again for publishing your work. I would not have guessed this chip could have done what you did! That was really awesome to see. I really liked the waveform summing to create a square wave from sine waves in your software. Took me back 40 years to my first class on Fourier series. And thanks for the Reset hint. That will save me some wear and tear on the USB connector...

    I implemented a dual amp LMH6643 (~$1.60), not pretty, lots of copper tape and solder braid. There is a bit of noise bouncing around and I definitely saw the repetitive glitches (see last photo). Of course I was powering the whole thing from my laptop also, so the Vbus is probably pretty dirty also. I added a couple of filter stages around 15MHz... I may have been a little too aggressive with the cutoff but -6dB is around 25MHz. The waveforms now look sinusoidal even above 25MHz.But man, a 4 dollar board and a $1.60 op-amp and you have a pretty decent AWG running at 250MHz. (Sorry, no, you can't do this on an ESP32 or even a Teensy 4.) I have not really dug into your code yet, just put a break loop after the sine generator section to measure specific frequencies. I hope to get some time t…

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    I implemented a dual amp LMH6643 (~$1.60), not pretty, lots of copper tape and solder braid. There is a bit of noise bouncing around and I definitely saw the repetitive glitches (see last photo). Of course I was powering the whole thing from my laptop also, so the Vbus is probably pretty dirty also. I added a couple of filter stages around 15MHz... I may have been a little too aggressive with the cutoff but -6dB is around 25MHz. The waveforms now look sinusoidal even above 25MHz.But man, a 4 dollar board and a $1.60 op-amp and you have a pretty decent AWG running at 250MHz. (Sorry, no, you can't do this on an ESP32 or even a Teensy 4.) I have not really dug into your code yet, just put a break loop after the sine generator section to measure specific frequencies. I hope to get some time to work on this a bit more sometime. It seems like the Raspberry guys have given us something that is part way between a microcontroller and an FPGA, with the crazy DMA and PIO state machines. I am looking forward to trying this in the Arduino IDE.One question: why do I have to power cycle each time after I make a change to get it to run. I do the CTL-F2 in Thonny thing and click on the run button, but it isn't until I pull and reinsert the USB connector that the program runs. Just a MicroPython-ism?

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  • Mini Babka (Sweet and Savory)

    Wow, the Hungarian in me is drooling. These are really beautiful. I may have to try this one! Maybe caramelized onions and shitake mushrooms for another savory version? Thanks! Bill

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  • Arbitrary Wave Generator With the Raspberry Pi Pico

    Finally got the chance to build this. I used the castellated edge connections and used 0603 2K (sorted) resistors. The -6dB roll off for a sinewave with a 10X probe on my Rigol scope is about 20MHz! Incredible, from a $4 microprocessor board. The scope photo shows a 25MHz sinewave.I am also running it at 250MHz for the main clock, so whatever RGCO specifies in his code, it runs twice as fast. My boards limit seems to be somewhere around 280MHz, which locks it up. I had to use flash_nuke.uf2 to unbrick the PicoPi. Ran fine again after that.Thanks RGCO, great work and thank you for showing the potential of this board. I will try to dig out some high speed op-amps tomorrow to see if I have anything that will buffer this for better performance. (I am looking forward to putting on an LCD also …

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    Finally got the chance to build this. I used the castellated edge connections and used 0603 2K (sorted) resistors. The -6dB roll off for a sinewave with a 10X probe on my Rigol scope is about 20MHz! Incredible, from a $4 microprocessor board. The scope photo shows a 25MHz sinewave.I am also running it at 250MHz for the main clock, so whatever RGCO specifies in his code, it runs twice as fast. My boards limit seems to be somewhere around 280MHz, which locks it up. I had to use flash_nuke.uf2 to unbrick the PicoPi. Ran fine again after that.Thanks RGCO, great work and thank you for showing the potential of this board. I will try to dig out some high speed op-amps tomorrow to see if I have anything that will buffer this for better performance. (I am looking forward to putting on an LCD also and trying out the PIO state machines.)

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  • Mandelbrot Set on Pi Pico / ILI9341

    Hi,Is there a schematic available? I can't tell from the photos where all of the wires are going.Thanks,Bill

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  • Single Sided PCB Home Fabrication (Presensitized PCB)

    Excellent video tutorial. I will have to try the photosensitized PCB material! A while back I did a toner transfer Instructable:https://www.instructables.com/Cheap-and-Easy-MP3-Shield-for-Arduino/I use a really simple and cheap bubble etcher. Basically a cheap aquarium pump, a length of aquarium tubing (with some pin holes from a heated pin) and a thin chamber made from two sheets of plexiglas separated by about a 1/4 inch, so that the tubing can be looped low in the chamber. It uses very little ferric chloride and etches in 10 to 15 minutes.For a UV exposure chamber (it appears the PCB material is made for exposure at 405nm, just like 3D printing resin), I use a stainless steel pot and a 60W UV lamp. I don't know if 60W is overkill for this, I use it for curing 3D resin prints.Remove the…

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    Excellent video tutorial. I will have to try the photosensitized PCB material! A while back I did a toner transfer Instructable:https://www.instructables.com/Cheap-and-Easy-MP3-Shield-for-Arduino/I use a really simple and cheap bubble etcher. Basically a cheap aquarium pump, a length of aquarium tubing (with some pin holes from a heated pin) and a thin chamber made from two sheets of plexiglas separated by about a 1/4 inch, so that the tubing can be looped low in the chamber. It uses very little ferric chloride and etches in 10 to 15 minutes.For a UV exposure chamber (it appears the PCB material is made for exposure at 405nm, just like 3D printing resin), I use a stainless steel pot and a 60W UV lamp. I don't know if 60W is overkill for this, I use it for curing 3D resin prints.Remove the handle from the lid (drill out/cut out the rivets), cut a rectangular hole in the lid to match the lamps LED area (a dremel with cut off discs works great) and drill 4 holes to match the lamps bezel mounting screws and then attach the lamp to the lid top with 4 screws that are slightly longer than the lamp's bezel screws. The pot prevents exposure to the UV light by outsiders and provides an lot of reflective surface internally. Plus you can use it with a 3D resin printer for print curing. Thanks again for the great Instructable.Cheap SS pot with SS lid:https://www.amazon.com/IMUSA-L300-40314-Stainless-8-Quart-Silver/dp/B0018KNC4C/ref=sr_1_12?crid=2RNBQA4P16BWJ&dchild=1&keywords=8+quart+stock+pot&qid=1590936873&sprefix=8+quart+st%2Caps%2C563&sr=8-12UV lamp, 60W, 405nm:https://www.amazon.com/dp/B081YWCNDS/ref=sspa_dk_detail_2?psc=1&pd_rd_i=B081YWCNDS&pd_rd_w=0VsoD&pf_rd_p=48d372c1-f7e1-4b8b-9d02-4bd86f5158c5&pd_rd_wg=EcVNs&pf_rd_r=4KTKHT2A8GMFWFVEMDX9&pd_rd_r=c231c296-aa86-4295-aed5-c7231e3a2a54&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzUVdCN1dQUDQzSFExJmVuY3J5cHRlZElkPUEwNDc5MjYwM1E1NkxKS1ZKRlNIVCZlbmNyeXB0ZWRBZElkPUExMDIzNjk0MjFYQzNKRE9SU1QyNyZ3aWRnZXROYW1lPXNwX2RldGFpbCZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=Cutoff Wheels for Rotary tools:https://www.amazon.com/Dremel-688-01-Piece-Rotary-Cut-Off/dp/B00005LEY1/ref=sr_1_4?crid=M7K29ZF70A5I&dchild=1&keywords=rotary+tool+cut+off+wheel&qid=1590938910&sprefix=rotary+tool+cut+off+%2Caps%2C180&sr=8-4

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  • dresch commented on dresch's instructable Micro Lathe Upgrade
    Micro Lathe Upgrade

    I use Simplify3D which has no problem reading this file in. But I have added a mm converted file to the motor mount step. See if that works for you.

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  • dresch commented on dresch's instructable Micro Lathe Upgrade
    Micro Lathe Upgrade

    Please set your slicer to inches not mm. Or if you can't do that, try scaling by 25.4.Let me know how that goes.

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  • Samytronix Pi: DIY Raspberry Pi Desktop Computer (with Accessible GPIO)

    A wonderful project. I really like the fact that you make the GPIO accessible. In the good old days PCs had parallel ports that could be used for controlling projects (not that I don't like USB interfacing but sometimes you just need to toggle a pin very fast.) Very aesthetically pleasing also. A great Linux learning system too.

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  • dresch commented on thatguyer's instructable The Algorithm Machine
    The Algorithm Machine

    Brilliant and beautiful. Thank you sir. That is a really gorgeous representation.Now I am going to do the old guy thing: when I was in undergrad when dinosaurs ruled the earth (along with PDP-8s) we had a sorting contest (8 bit integers) in my first algorithm class. One individual had a sort time orders of magnitude less than everyone else and I will never forget the way he did it. He created an array of 256 words. He then took the data set and counted thru it once adding one to whatever array bin the data value equaled. So if the data value was 125 he added one to bin 125: mycount[125]++. Then he simply wrote out the number of non-zero bin values the number of times that bin address held. Instant sorting by counting. If bin 7 (mycount[7]) had was equal to 3 he wrote to the sorted array:…

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    Brilliant and beautiful. Thank you sir. That is a really gorgeous representation.Now I am going to do the old guy thing: when I was in undergrad when dinosaurs ruled the earth (along with PDP-8s) we had a sorting contest (8 bit integers) in my first algorithm class. One individual had a sort time orders of magnitude less than everyone else and I will never forget the way he did it. He created an array of 256 words. He then took the data set and counted thru it once adding one to whatever array bin the data value equaled. So if the data value was 125 he added one to bin 125: mycount[125]++. Then he simply wrote out the number of non-zero bin values the number of times that bin address held. Instant sorting by counting. If bin 7 (mycount[7]) had was equal to 3 he wrote to the sorted array: 7, 7, 7. Then if the next non-zero bin was 11 and it contained 5, the list became: 7,7,7,11,11,11,11,11... and so on.I must say I have used this a number of times in my computing life... if your data falls within certain well defined limits, it is a fantastic algorithm.

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  • dresch commented on ossum's instructable Dieselpunk FPV Tractor

    Love the design. Really awesome. That printer bed is sweet... I wonder if they sell those separately. One suggestion, something for all that acetone spillage. A solvent dispenser will really help. McMaster Carr sells one with a 27 gauge needle that really puts a drop or line where you need it. I use: https://www.mcmaster.com/1902T111I am sure Amazon carries them also. Great Work!

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  • dresch commented on ThomasVDD's instructable Upgrade Your CNC

    Hi Thomas,Great Instructable! Thanks. I have the big brother of your mill and have been going thru some of the same steps. Mine is a 2417 with the dual uprights. Surprisingly rigid. Got my motor holder off of Thingiverse, similar to this:https://www.thingiverse.com/thing:2707601Came across this today, which is a fine intro to CAM on a CNC mill/router:https://www.inventables.com/projects/kevin?ref=Intercom&utm_source=Intercom&utm_medium=Welcome%20Email%20Series&utm_campaign=2%20-%20F360%20Beginners-%20BtestThanks, Bill

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  • Have you considered using a line of MEMS microphones and LEDs, then you won't need motion control just electronic switching. Cost does not seem that prohibitive to put 10 to 50 pairs in a line...https://www.mouser.com/Sensors/Audio-Sensors/MEMS-...Very cool Instructable. Need to study that lock-in amplifier circuit!

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  • Wow! I am really impressed. I have often used milk bottle polypropylene material for projects but never thought to weld it. DUH! This project is awesomely well-done. And now I can use old milk jugs to build protective covers and bellows for tools in my shop, add opaque windows in 3D prints, etc. I really like the battery holder also. A deep bow and thank you. (Has anyone tried cutting this material on a Cricut type cutter? You may be able to go into the GlowBot business... of course I know a lot of the charm is in the hand work. But then building a PP spot welder would be cool also.)

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  • dresch commented on kirthik vasan's instructable Hot Ice

    If you inserted a rod with a couple of RGB LEDs on the end ito the solution, It would be neat to see if that crystal dandelion would glow different colors...

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  • http://www.ebay.com/itm/V-Twin-V-Type-Mini-Hot-Liv...Greg,Lovely air engine!Have you seen these... you can run a plastic engine with steam. I have one and it cranks like the devil with the tuna-can boiler. My guess is the cylinder and piston are UHMW or some other lubricious engineering plastic that can take a little heat. Bill

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  • dresch commented on gzumwalt's instructable Flying Pumpkin (Balloon)

    Yeah, I have to totally agree with that... my first thought was "YOU CAN ACTUALLY CONTROL THE BALLOON'S FLIGHT. WOW." Probably a great personal fan too. "My left ear needs cooling now also."Another in a long line of awesome projects from gzumwalt. Thanks you!

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  • dresch commented on TinkerJim's instructable Wooden Finger Engine

    Hi Dr. Senft,Great Instructable and video. I saw your article in Nuts & Volts on the CSS555 and then went to your Instructables list. (To those who are reading this, Dr. Senft invented, among other things, the type of "coffee cup" low delta-T Stirling engine you see all over, including in Instructables.) You really should publish a collection of your articles from Live Steam in a book including the steam powered Tonka truck, the Moriya Fan, the thimble engine and that wonderful little O-gauge train. I think a whole new generation of builders would enjoy that immensely. Thanks for continuing to put forth such awesome projects. -Bill

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  • Awesome Instructable, even if I did have to look up IB and MYP. ;-)This is a Senft Stirling engine, first conceived and developed by Dr. J. R. Senft of University of Wisconsin River Falls, during a friendly competition with Dr. Ivo Kolin of University of Zagreb in the 1980's to build an engine that would run on the lowest temperature differential. Dr. Senft, an awesome machinist as well as a mathematician, was an inspiration to me as a teenager reading Live Steam magazine, and one of the reasons I became an engineer. A neat illustration of the engine and the story behind it is here: http://www.animatedengines.com/ltdstirling.htmlThanks and keep on making Instructables!

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