Social Distancing Laser Hat

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Mark your personal space with the Social Distancing Laser Hat! This will draw a circle of approximately 2m radius around you, letting you know if you're too close to someone or if they're too close to you! Video here: https://www.youtube.com/watch?v=lmvdseag7vk I'm using a 1mW Class 1 laser, which is non-harmful to eyesight (but don't stare at it ffs). Bystanders would not be in any danger. Full Fusion 360 model available here! https://a360.co/2VNXtfa Bill of materials: (actual parts / examples detailed below) 3D Printed parts as per Fusion 360 model. I printed on a Prusa MK2.5S MMU2S, using PrusaSlicer and the default 0.35mm FAST profile, which worked flawlessly first time. 2off skateboard bearings 22mm x 8mm x 7mm 1off 6V DC geared motor 1off 4xAA batter holder with switch 4off M3 x 5mm screw (button / pan / socket head, etc., not countersunk) 1off M3 x 8mm screw 4off M3 screws for mounting to hat, length selected according to particular hat (mine are 18mm). 5off standard M3 lock nut - 4 for mounting the module to a hat, the 5th is held captive in the laser holder, then the M3x8 screw is threaded through it to lock the shaft. I haven't included any screws or nuts in the F360 model because I'm lazy. The lower skate bearing probably isn't strictly necessary. If removed, adjust the length of the bearing spacer part to compensate. I made the 8mm guide shaft between the motor and the laser holder from 8mm stainless rod and used a grub screw to locate on the flat face of the motor D-shaft. In principle, the 3D printed shaft should work just as well. None of the links below are sponsored or affiliated in any way. They are for reference only. I already had the laser pointer, motor, bearings and battery holder from previous projects. They're all common models, still available from a bunch of sellers. The motor used is a 6V DC geared motor with a body that has a 12mm diameter on the round sides and 10mm across flats. Lots of models are available in all sorts of gear ratios from all the usual suspects. Anything between 500-1500 rpm (no-load) will work. The lower rpm models have a nice, less violent sweeping effect. 1500 rpm almost gives a pretty good POV (persistence of vision) effect, but the laser pointer needs to be balanced well to minimise vibration. The variants with a D shaft or an M3 x 55mm threaded shaft can be used by choosing the appropriate guide shaft. The M3 x 55mm shafted motor variants guide shaft needs an M3 nut at each end (and a shakeproof washer wouldn't go amiss at one end) Example motors: 500 rpm version with long shaft - Probably wouldn't choose anything slower than this https://www.amazon.co.uk/dp/B0753G5268?ref_=pe_3187911_264767211_E_301_dt_1 The video shows a 1490rpm motor from RS. For this exact model, the sticker around the motor body had to be removed! https://uk.rs-online.com/web/p/dc-geared-motors/8347675/ The 1000 or 1200 rpm variants of this should work well. https://www.amazon.com/BoMiVa-1000RPM-1200RPM-Deceleration-Reducer/dp/B07ZT2C614/ref=sr_1_21?dchild=1&keywords=6V%2BDC%2Bgeared%2Bmotor%2B1000RPM&qid=1587428800&sr=8-21&th=1 Laser - Choose one with a sliding switch rather than a momentary pushbutton so it stays on. Mine is 16mm in diameter. If using a different laser pointer, the 3D model will need adjusting. This can be done (to an extent) by adjusting the user parameter LASER_DIAMETER. Some other tweaks may be required if vastly different. The position of the laser within the laser holder should be adjusted to find the center of gravity to reduce vibration. This can be done by attaching just the laser holder to the guide shaft and adjusting the laser position until the shaft can stand on its own (or as close as possible - might not be possible in practise) Loads of dimensionally identical models to mine are available. UK and USA examples below: UK https://www.amazon.co.uk/dp/B07Q81Y5PS/ref=pe_3187911_185740111_TE_item USA https://www.amazon.com/Lavibest-Charging-Interactive-Exercising-Interesting/dp/B082TMB4G1/ref=sr_1_12?dchild=1&keywords=cat+laser+pointer&qid=1587426179&sr=8-12 Bearings - Any 22mm OD x 8mm ID x 7mm thickness skateboard bearings will do. I have a stash of Bones China Reds: https://www.amazon.co.uk/dp/B000FDRQ1S?ref_=pe_3187911_264767211_E_301_dt_1 Battery holder - 4x AA with switch and 15cm wires. Probably available everywhere, UK and USA links for exact model below. UK https://www.ebay.co.uk/itm/AA-x-4-Enclosed-Battery-Holder-Box-with-Switch-15cm-Wires/281526444568?hash=item418c48a218:g:PQ8AAOSwnDxUiJ75 USA https://www.ebay.com/itm/4X-AA-DIY-Battery-Holder-Case-Box-6V-5V-With-Power-Switch-Bare-Wire-Ends/253572474000?hash=item3b0a18e490:g:7oMAAOSwmcBa2TqX Hat: Any rigid hat will do, ideally one with internal strapping or a liner so the mounting screws don't dig into your head. A builder's hard hat or skateboard helmet would be fine. Choose one that you don't mind drilling holes into.

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