Useless box "Hank" Style - Remixed

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Useless box "Hank" Style - Remixed Credit where it's due. This is a primarily a remix of... Useless box "Hank" Style https://www.thingiverse.com/thing:4524815 by Blayder, originally posted on July 5, 2020. - - - - - - - - - - - - - - - - - - - - - I've also directly used or modified elements of the models below... Bottom plate for Hank https://www.thingiverse.com/thing:5405358 by WessieLin, posted March 14, 2023, - - - - - - - - - - - - - - - - - - - - - Hank! https://www.thingiverse.com/thing:5229056 by Finch666, posted February 2, 2022, and - - - - - - - - - - - - - - - - - - - - - modified arm https://www.thingiverse.com/thing:5213147 also by Finch666, posted January 23, 2022. - - - - - - - - - - - - - - - - - - - - - Schalter (Umschalter) https://www.thingiverse.com/thing:6179133 by sonz_nix, posted August 20, 2023. - - - - - - - - - - - - - - - - - - - - - Last but not least, a sincere thank you to a good friend and former co-worker, WTS, who provided important help with the Arduino sketch. Even though I started with a sketch from one of the models above, I struggled to get what I wanted. Without him, this project would never have seen the light of day. I've lost track of exactly which files from each of the models listed above contributed to my final version, either as originally published or as a basis for a modified part. I am pretty sure some aspects of each of those models is in the end product. I no longer have this piece in hand, so nothing is available to measure or disassemble for a hands-on memory check. All I have are files, photos and my memory. All below is the best I can reconstruct this project. = = = = = = = = = = = = = = = = = = = = = What's Changed From Original: Added base Added Buck Converter Added power LED Incorporated low-effort main switch Modified or added various parts Randomized "moves" in the Arduino sketch - - - - - - - - - - - - - - - - - - - - - This is not a trivial project It was a long and torturous effort. The primary difficulties were, a) switch effort vs. servo strength, and b) fitting everything into the chest as it was designed. Some elusive printer problems along the way added to the fun and games. I went through several combinations of toggle switches and servo types. Eventually I realized that for any toggle switch I could find, the servo needed to operate it with suitable force was not going to fit into the box. I finally opted for a 3D printed slide switch which incorporates a limit switch with a roller arm, from the "Schalter" model in the list above. That provided a switch with an acceptably light operating effort, a major breakthrough. The new style switch allowed going back to the common low-end 9g plastic-geared SG90 servo and retained the servo mounting features of the original model. The new switch did, however, require modification of the front face of the chest and to Hank's head to accomodate it. I took the easy way out from the ultra-compact original chest design by putting most components in a custom base. The new base contains all the components except the main switch and the two servos. The last straw driving me to a base/enclosure was discovering that the voltage limit of the SG90 servos is 6.0 volts. Operating directly from a 9 V battery at 150% of the maximum rated voltage seemed unwise so I incorporated a buck converter to drop the battery voltage to 6 volts. = = = = = = = = = = = = = = = = = = = = = BILL OF MATERIALS: 3D Printed Parts: Box: Bodenplatte_unten.stl (unmodified; OP's original filename) Body Plate - Upper rev 1.stl Chest Bottom - rev 2.stl Chest_Top.stl Hank Solid rev 11.stl Lid Tentacle rev 3.stl Nano Base rev 2.stl Tentacle - Hand rev 1.stl (1 X for all above) - - - - - - - - - - - - - - - - - - - - - Switch: Side Plate rev 2.stl Switch Block rev 1.stl Toggle rev 3.stl Switch Handle Spacer rev 0.stl (1 X for all above) - - - - - - - - - - - - - - - - - - - - - Base: Base rev 9.stl Bottom rev 2.stl Bus Support rev 0.stl 3 X Cover Pedestal rev 0.stl Nano Base rev 2.stl - - - - - - - - - - - - - - - - - - - - - Purchased/Parts Bin Parts: 2 X SG90 servos with nylon control horn set and associated mounting hardware https://www.amazon.com/Dorhea-Arduino-Helicopter-Airplane-Walking/dp/B07Q6JGWNV/ref=sr_1_4?crid=X3WFR0RB1885&keywords=sg90&qid=1704597292&s=toys-and-games&sprefix=sg90%2Ctoys-and-games%2C101&sr=1-4&th=1 1 X Micro Limit Switch 5A SPDT Micro Switch Roller Lever Arm (main switch) https://www.amazon.com/gp/product/B07X142VGC/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 1 X Arduino Nano https://www.amazon.com/HiLetgo-ATmega328P-Controller-Compatible-ATmega328/dp/B09KGVDXZY/ref=sr_1_1_sspa?crid=3QRW0AN4ZP05B&keywords=arduino+nano&qid=1704597340&s=toys-and-games&sprefix=arduino+nano%2Ctoys-and-games%2C102&sr=1-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1 1 X 5mm Micro Mini Slide Switch, 3 Pin, 2 Position SPDT Latching Toggle Switch, Panel Mount (battery switch) https://www.amazon.com/gp/product/B099N3HFPG/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1 1 X LM2596S Buck Converter DC to DC Converter High Efficiency Voltage Regulator 3.0-40V to 1.5-35V Buck Converter Adjustable Power Supply Module https://www.amazon.com/gp/product/B08Q2YKJ6Q/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1 1 X 9V battery 1 X 9V battery snap connector 1 X 3 mm green LED (power indicator) 1 X 1.5K 1/8 watt resistor (brown/green/red - power indicator LED) 5 X M3 x 3 x 5mm female Press-in Threaded Brass Heat Set Inserts (cover screw nuts [X 3] and Bodenplatte_unten to Chest bottom [X 2]) https://www.amazon.com/gp/product/B07D683Q26/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1 4 X M2 X 6mm Phillips Round Head Self Tapping Screws (battery switch and buck converter) https://www.amazon.com/gp/product/B01M0DCPQ5/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 2 X M3 X 40 mm Allen head cap screws (chest to base) 2 X M3 Nylock self-locking nuts https://www.amazon.com/Bolt-Base-Stainless-Insert-Nylock/dp/B00B3RIHV8/ref=sr_1_11?crid=3VC6W8CRWU9RK&keywords=m3%2Bnylock&qid=1704662247&s=hi&sprefix=m3%2Bnylock%2Ctools%2C124&sr=1-11&th=1 Various other M3 screws M3 flat washers Thin (~ 1/16") double stick tape Pin headers, straight and right-angled 2 X pin header jumpers Wire/solder/flux Cyanoacrylate gel = = = = = = = = = = = = = = = = = = = = = Assembly Notes: - - - - - - - - - - - - - - - - - - - - - Base: The bus support is optional. It holds a small piece of universal PCB configured to create a pair of 10 pin buses, one each for + 5V and GND, made from four 5 pin male pin headers. A jumper connects each pair together, leaving 8 remaining pins in each bus. Most all of the common points at +5 V and GND connect to these. The Nano base is a small plate with three cones. The Nano screw holes will sit on the three cones and are secured with a drop of cyanoacrylate gel. The fourth screw hole is not used because of interference with some of the connections to the Nano. The plate gets glued to the base, allowing some flexibility in the location. The program should be uploaded to the Nano before Nano and Buck Converter are fixed in their final locations. The Converter will interfere with connecting a USB cable to the Nano if both are fixed in place. Where possible, Dupont jumpers were used to make connections, soldered at one end and plugged into pin headers at the other. The Buck Converter should be pre-adjusted on the bench for a 5-6 V output before installation. The servos operate OK at 5 V; 6 V is their max rating. Male right-angle pin headers are soldered to the Nano only at the pins that will be used. I chose to use pluggable electrical connections between the chest components and the base, largely because this was a work in progress and the design was somewhat fluid throughout. It would be a simple matter to make a hole between the two pieces and make direct connections. If done, the paragraph below can be ignored. Male straight pin headers (2 X 3 pin for servos; 1 X 2 pin for main switch) with wires already soldered to them are inserted into slots in the top of the box and glued from the bottom with cyanoacrylate gel. Those pins provide connection points between the servo and switch leads from the chest to the components in the base. There are embossed labels on the base showing the correct orientation of the servo pulse plugs. The switch leads have no polarity. They can be plugged to the 2 pin header in either order. The Nano and Buck Converter have LEDs that tend to illuminate the base in a dark environment. If that is unacceptable, it may be desireable to mask them with paint, putty or a shield of some kind. - - - - - - - - - - - - - - - - - - - - - Chest: The servos are attached to the Body Plate - Upper. The lid servo is mounted with small machine screws (M2 or M2.5, no longer sure) with hex nuts embedded in hex pockets below. The Bodenplatte_unten requires two threaded brass inserts to be pressed into the holes in the legs and is secured to the Chest Bottom by two M3 screws from the outside of the chest. The Body Plate upper, with servos attached is attached by two 40 mm M3 Allen head screws that pass through the Bodenplatte_unden (Body Plate lower), the Chest bottom and the Base enclosure. They are secured with two M3 Nylock nuts inside the base. The main switch body is glued into the chest front face. The switch may interfere with subsequent disassembly so should only be installed after the servos and internal parts are in place as desired. Switch must be installed so contacts are closed when slide is up. The Switch Handle Spacer was is glued to the Slider with the long part of the spacer up. Hank's head masks one of the screw heads for the M3 X 40 mm screws that hold the chest to the base. In order to preserve the ability to disassemble the chest if necessary, double stick tape is used to hold the head in place. It should be installed last. - - - - - - - - - - - - - - - - - - - - - Arduino Sketch: Hank has nine distinct moves, i.e. ways by which he turns off the main switch. At least one takes about ten seconds. The program now selects the next move at random, so any one of the nine, including the last one used, can come up next. The sequence does not repeat. The random number generator is seeded from a millis() call at the time the user/victim operates the main switch for the first time after a power up, favoring a different sequence of moves each time the board is powered up. The program only uses about 20% of the Nano program memory. It should be possible to use a different processor for this project if desired. The current capability of the processor is not an issue since the Buck Converter supplies the servo power.

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