[{"data":1,"prerenderedAt":629},["ShallowReactive",2],{"project-40003710":3},{"id":4,"name":5,"line":6,"line_source":7,"title":8,"url":9,"domain":10,"maker":11,"posted_at":12,"year":13,"points":14,"comments":15,"rank_in_year":16,"shown_in_year":17,"top":18,"tier":19,"category":20,"subcategory":21,"format":20,"keywords":22,"reception":28,"sentiment":29,"stance_mix":30,"scored_comments":35,"aspects":36,"strip":47,"post_text":50,"what":51,"said":97,"maker_in_thread":213,"shape":225,"grid":229,"attempts":590,"same_week":591,"maker_shows":18,"maker_hidden":621,"reader_version":622,"card":623},"40003710","OptiGap sensor","A new sensor out of 3D printer filament for my PhD","title","Show HN: I made a new sensor out of 3D printer filament for my PhD","https:\u002F\u002Fpaulbupejr.com\u002Fdeveloping-the-optigap-sensor-system\u002F","paulbupejr.com","00702",1712851563,2024,886,130,12,3515,1,"legend","hardware","soft robotics sensor",[23,24,25,26,27],"bend sensor","soft robotics","optical fiber sensor","tpu filament","bend localization","mixed",0.379,{"positive":31,"neutral":32,"mixed":33,"critical":34},33,34,0,7,74,{"docs":37,"idea":39,"performance":41,"design":42,"pricing":44,"execution":45},{"positive":38,"critical":18},6,{"positive":40,"critical":33},13,{"positive":33,"critical":18},{"positive":33,"critical":43},2,{"positive":33,"critical":18},{"positive":46,"critical":18},3,[48,48,48,48,46,48,49,18,43,49,46,46,48,48,46,43,48,48,46,43,46,48,33,48,48,46,48,46,48,46,46,48,48,48,48,48,48,48,48,48],5,4,"Here's a \"behind-the-scenes\" look at my development of a cool sensor during my PhD (electrical engineering). This sensor is only about 1\u002F3 of my total research for my degree and took about a year.\n\nI've been on HN for a while now and I've seen my fair share of posts about the woes of pursuing a PhD. Now that I'm done with mine I wanna share some anecdotal evidence that doing a PhD can actually be enjoyable (not necessarily easy) and also be doable in 3 years.\n\nWhen I started I knew I didn't want to work on something that would never leave the lab or languish in a dissertation PDF no one will e",{"problem":52,"audience":64,"pricing":73,"motivation":74,"time_to_build":80,"stack":84,"openness":95,"stage":95,"team_size":96},{"value":53,"source":54,"evidence":55},"Sensing where and how a soft or flexible structure bends without rigid electronics","inferred",[56,58,61],{"id":57},"post",{"id":59,"by":11,"text":60},"40004280","Yeah initially doing literature review was a bit daunting because of all this existing work, especially FBG-type sensors, but this idea is so fundamentally simple that its been…",{"id":62,"by":11,"text":63},"40003914","Good point -- I need to better explain what \"bend localization\" means on a more practical level pretty early on.",{"value":65,"source":54,"evidence":66},"Soft robotics and sensing researchers",[67,70],{"id":68,"by":11,"text":69},"40006526","There are a lot of similarities in the approach to the linked paper (which is a very cool concept) and I saw a lot of similar concepts in my lit review. At a high level, my…",{"id":71,"by":11,"text":72},"40004607","The finger bending example is certainly a classic for something like this but I think it truly shines in soft robot examples like flapping wing robots or swimming finned robot,…",null,{"value":75,"source":76,"evidence":77},"Build a simple, mechanically transparent sensor for soft robotics, and do PhD research that leaves the lab","maker",[78,79],{"id":57},{"id":71,"by":11,"text":72},{"value":81,"source":76,"evidence":82},"About a year",[83],{"id":57},[85,89],{"value":86,"source":76,"evidence":87},"pyqtgraph",[88],{"id":57},{"value":90,"source":76,"evidence":91},"Kalman filter for 1D signal filtering",[92],{"id":93,"by":11,"text":94},"40008507","I used it more for future-proofing in case I wanted to do sensor fusion or something like that later on -- currently it's just 1D filtering so I could have used anything. Also…","unknown","solo",{"praise":98,"objections":130,"requests":149,"questions":167,"alternatives":182},[99,115],{"value":100,"source":101,"evidence":102},"Clear, readable write-up","commenter",[103,107,111],{"id":104,"by":105,"text":106},"40015083","jallmann","What an excellent write-up. Very clearly explained, and the use of gifs and visuals to illustrate concepts was spot-on. I'm only a software engineer with a limited understanding…",{"id":108,"by":109,"text":110},"40004286","bythreads","Congrats and if I may; your blog post should be how ph.d's are done - readable, understandable and devoid of techno mumbling.",{"id":112,"by":113,"text":114},"40004300","lifeisstillgood","“I stuck a piece of plastic to my desk, it bent as I did it, I had time to investigate and skills to get a whole PhD out of that” And this dear worker drones, is why schedule…",{"value":116,"source":101,"evidence":117},"Clever, simple idea",[118,122,126],{"id":119,"by":120,"text":121},"40005855","rcarmo","This, sir, is sheer genius. I genuinely loved your approach and the way you wrote it down.",{"id":123,"by":124,"text":125},"40003826","Balvarez","Wow that's super cool! Very nice work",{"id":127,"by":128,"text":129},"40004048","Projectiboga","Solid job, and congratulations on doing something useful and hitting the program with the goal to make something tangible and getting out promptly.",[131,142],{"value":132,"source":101,"evidence":133},"Multiple simultaneous bends produce ambiguous readings",[134,138],{"id":135,"by":136,"text":137},"40007880","robryk","I don't understand what happens when the sensor is bent in more than one location. At the beginning you mention a ToF sensor, which made me think that you're looking at…",{"id":139,"by":140,"text":141},"40004922","crote","What an absolutely amazing idea, great work! Your sensor data seems to have quite large \"dead zones\" - those should be trivially fixable by reducing the inter-sensor distance,…",{"value":143,"source":101,"evidence":144},"Manufacturing the encoded multi-fiber junctions is hard to scale",[145],{"id":146,"by":147,"text":148},"40005835","knodi123","This is interesting! Although the way you have to have log2 fibers, and a different encoding in each junction, presents quite a manufacturing challenge. Oh well, it's not a…",[150,160],{"value":151,"source":101,"evidence":152},"Explain what the sensor measures earlier in the post",[153,157],{"id":154,"by":155,"text":156},"40003846","porphyra","That's super cool and I hope you don't mind a little bit of unsolicited feedback but the first question everyone's asking is \"what does it do?\" At present the blog post starts…",{"id":158,"by":128,"text":159},"40003986","Hi, what kind of sensor? When posting to the public you should mention the subject of what can be sensed or scanned early on.",{"value":161,"source":101,"evidence":162},"Compare with fiber-optic data glove approach",[163],{"id":164,"by":165,"text":166},"40005363","mhb","Thanks for sharing your work. Would you be able to compare your device to the fiber optic one used in the data glove (e.g.,…",[168,175],{"value":169,"source":101,"evidence":170},"Why TPU rather than regular optical fiber",[171],{"id":172,"by":173,"text":174},"40003924","lttlrck","This is really really cool, but why does it depend on TPU? Wouldn't it work with regular fiber optic? Or does it come down to economics?",{"value":176,"source":101,"evidence":177},"Why use a Kalman filter",[178],{"id":179,"by":180,"text":181},"40006588","doug_life","Very cool to see how it all came together. Can you elaborate on why you chose to use a Kalman filter in your signal chain?",[183,194,202],{"value":184,"source":101,"evidence":185},"Fiber Bragg grating sensors",[186,190],{"id":187,"by":188,"text":189},"40005804","riedel","Have you explored fiber bragg grating. 10 years ago a student of mine semi successfully explored sensing the shape of firefighter hose using that technique. Seems to gain new…",{"id":191,"by":192,"text":193},"40004162","ericdfoley","Not quite the same thing, but this reminds me of DAS using fiber optic cable for various acoustic sensing tasks--basically as an alternative to geophones\u002Fhydrophones. There have…",{"value":195,"source":101,"evidence":196},"Distributed temperature sensing and DAS fiber sensing",[197,201],{"id":198,"by":199,"text":200},"40004553","uoaei","Similar concept but for temperature (linked on HN a while back): https:\u002F\u002Fen.m.wikipedia.org\u002Fwiki\u002FDistributed_temperature_sensing",{"id":191,"by":192,"text":193},{"value":203,"source":101,"evidence":204},"Nintendo Power Glove",[205,209],{"id":206,"by":207,"text":208},"40007930","downrightmike","Isn't this just the same tech as the first Nintendo Power Glove had? https:\u002F\u002Fwww.youtube.com\u002Fwatch?v=3g8JiGjRQNE They put light down a tube and then measured the light to trigger…",{"id":210,"by":211,"text":212},"40003890","blkhawk","on first blush that sounds like a better version of the way the Nintendo power-glove detected finger bending.",{"comments":214,"answered":40,"key":215},29,[216,219,222],{"id":217,"text":218},"40004420","Indeed! How do you know her?",{"id":220,"text":221},"40006573","There are a lot of cool applications indeed! I was able to use it to do gait for a soft robot \"leg\", but I have to wait for the paper to be published later this year before going…",{"id":223,"text":224},"40003955","Very much so!",{"commenters":226,"max_depth":48,"maker_replies":214,"first_comment_mins":227,"lifespan_hours":228},80,10,72,[230,234,236,239,242,246,250,252,255,258,259,262,263,264,266,268,269,272,273,275,279,282,285,288,292,295,299,302,306,308,310,313,315,318,319,322,325,328,332,335,337,339,341,344,347,350,352,355,359,363,366,369,373,375,380,382,384,387,389,392,395,397,400,402,404,407,408,411,415,419,422,425,428,431,434,437,440,443,445,447,450,452,454,457,459,460,464,466,468,470,472,476,480,484,486,488,491,493,495,499,501,503,507,509,510,513,517,519,523,527,531,533,535,537,541,543,546,548,552,556,558,562,566,569,571,576,578,582,586,588],[231,33,48,232,233,33],"40004358","maker\u002Fpositive\u002Fdocs","raphman",[217,33,33,235,11,18],"maker\u002Fneutral\u002Fnone",[237,33,33,238,233,33],"40006548","commenter\u002Fneutral\u002Fnone",[240,33,33,238,241,33],"40008451","smoyer",[243,18,48,244,245,33],"40008147","project\u002Fpositive\u002Fidea","OisinMoran",[247,18,46,248,249,33],"40008670","project\u002Fneutral\u002Fperformance","spiderxxxx",[251,18,33,238,245,33],"40010814",[253,18,33,238,254,33],"40015535","wcrossbow",[256,43,48,244,257,33],"40005314","jjk166",[220,43,33,244,11,18],[260,46,46,235,261,33],"40003841","klysm",[223,46,33,238,11,18],[104,49,48,232,105,33],[265,49,33,238,11,18],"40016900",[191,48,46,267,192,33],"project\u002Fneutral\u002Fidea",[59,48,33,267,11,18],[270,48,33,271,192,33],"40004368","commenter\u002Fpositive\u002Fidea",[139,38,48,244,140,33],[274,38,33,248,11,18],"40006023",[276,38,48,277,278,33],"40006124","maker\u002Fpositive\u002Fnone","gaudystead",[280,38,46,248,281,33],"40009641","liamwire",[283,34,46,267,284,33],"40007091","abraae",[286,34,33,238,287,33],"40007141","cglace",[289,34,33,290,291,33],"40007160","other\u002Fcritical\u002Fperformance","risenshinetech",[293,34,33,294,284,33],"40007245","other\u002Fneutral\u002Fperformance",[296,34,18,297,298,33],"40007256","project\u002Fcritical\u002Fdesign","speps",[300,34,18,301,284,33],"40007289","project\u002Fcritical\u002Fperformance",[303,34,46,304,305,33],"40007580","project\u002Fneutral\u002Fdesign","schrectacular",[307,34,46,304,284,33],"40008084",[206,309,46,267,207,33],8,[311,309,48,244,312,33],"40009980","Doxin",[135,314,46,267,136,33],9,[316,314,46,267,317,33],"40009986","mariusor",[187,227,46,267,188,33],[320,227,33,321,11,18],"40005947","maker\u002Fneutral\u002Fidea",[323,227,48,244,324,33],"40007527","Prcmaker",[326,227,18,327,324,33],"40007500","project\u002Fcritical\u002Fpricing",[329,227,33,330,331,33],"40024408","other\u002Fneutral\u002Fnone","araes",[333,227,33,334,324,33],"40030005","other\u002Fneutral\u002Fpricing",[336,227,33,334,331,33],"40032079",[108,338,48,232,109,33],11,[340,338,33,238,11,18],"40004664",[342,16,48,244,343,33],"40008715","karambahh",[345,16,33,346,11,18],"40011954","project\u002Fneutral\u002Fexecution",[348,40,46,235,349,33],"40004705","wholinator2",[351,40,33,235,11,18],"40004913",[353,40,48,277,354,33],"40008515","atlas_hugged",[356,40,18,357,358,33],"40020538","maker\u002Fcritical\u002Fnone","fpgamlirfanboy",[360,361,46,267,362,33],"40005172",14,"skoocda",[364,361,33,365,11,18],"40012005","project\u002Fpositive\u002Fexecution",[146,367,18,368,147,33],15,"project\u002Fcritical\u002Fexecution",[370,371,46,346,372,33],"40004402",16,"teucris",[374,371,33,346,11,18],"40004660",[376,377,48,378,379,33],"40003909",17,"maker\u002Fpositive\u002Fidea","moralestapia",[381,377,33,235,11,18],"40003989",[383,377,48,277,379,33],"40004208",[385,377,46,267,386,33],"40004343","kobalsky",[388,377,33,267,11,18],"40004492",[390,377,46,267,391,33],"40004529","georgeburdell",[393,377,33,394,379,33],"40004831","commenter\u002Fneutral\u002Fidea",[396,377,33,394,391,33],"40005419",[154,398,18,399,155,33],18,"project\u002Fcritical\u002Fdocs",[62,398,33,401,11,18],"maker\u002Fneutral\u002Fdocs",[403,398,46,267,155,33],"40003972",[405,398,46,267,406,33],"40004072","oersted",[71,398,33,267,11,18],[409,398,46,267,410,33],"40004593","IMTDb",[412,398,46,413,414,33],"40004653","project\u002Fneutral\u002Fdocs","devwastaken",[416,398,48,417,418,33],"40006606","project\u002Fpositive\u002Fdocs","yoz",[420,398,33,330,421,33],"40005480","Netcob",[423,398,33,330,424,33],"40005818","sandebert",[426,398,33,330,427,33],"40005927","stavros",[429,398,33,330,430,33],"40006028","cush",[432,398,33,330,433,33],"40007388","Smoosh",[435,398,33,330,436,33],"40010246","tomcam",[438,398,46,267,439,33],"40005771","Cerium",[441,398,33,238,442,33],"40006039","nuancebydefault",[444,398,48,417,155,33],"40006064",[446,398,33,238,442,33],"40006238",[448,449,48,277,324,33],"40007465",19,[451,449,33,235,11,18],"40012010",[164,453,46,267,165,33],20,[455,453,46,267,456,33],"40005425","hypercube33",[458,453,33,394,165,33],"40005534",[68,453,33,267,11,18],[461,462,48,244,463,33],"40013605",21,"eigenvalue",[119,465,48,244,120,33],22,[198,467,46,267,199,33],23,[112,469,48,277,113,33],24,[471,469,33,277,11,18],"40004506",[473,474,18,297,475,33],"40005050",25,"maxnoe",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advisor",417,"data",{"id":618,"name":619,"points":620,"category":20},"40014937","Recovery Kit 2",403,false,"v2",{"id":624,"name":5,"line":6,"ai":621,"cat":20,"year":13,"points":14,"comments":15,"rec":28,"s":625,"top":18,"kw":626,"maker":11,"domain":10,"tier":19,"attempts":33,"strip":627,"url":9,"mix":628,"praise":100,"objection":132,"sub":21},40003710,0.38,[23,24,25,26,27],"5555354124335532553235055353533555555555",[31,32,33,34],1794036652936]