Helmet Strap for Camera Case

How could I create a helmet strap for a camera case so I can attach it to my head while bodyboarding?

Topic by bearsfan654   |  last reply


Wearable laptop computer sling for stand-up use?

I want to stand up while using my laptop, but instead of putting the laptop on a stand, I want to WEAR it like a sling in front of me while I'm using it.  Maybe something strappy that would hold the laptop securely while I type etc. It's a 15" (diagonal) screen laptop, and not especially lightweight, so I'd prefer not to support its weight entirely by my neck. I'd appreciate any ideas for how to make something like that!

Question by wimsycat   |  last reply



Can someone make an instructable for this?

Hey,This is my first post on the Instructables community section, so here goes.I've been looking at this product for awhile now: ThisHowever, I don't live in the states, and have to pay for massive postage costs for something so simple.So, I'm requesting if someone could help me by making a DIY tutorial version (an Instructable :P) of this?I need it desperately. Plus it'd increase my nerdiness by 340% _~Tim.P.S - Sorry for any spelling errors, or if I posted this in the wrong section or anything of the sort.

Topic by Crystalmyst   |  last reply


how do you pick up the signal from the chest strap of an un-coded heart rate monitor?

I've got a Polar heart rate monitor, which includes a chest strap and a watch. The strap sends out an RF pulse for each heartbeat it detects. These pulses then get counted and then displayed by the watch on your wrist. I would like to be able to intercept this RF pulse and do my own thing with it. My initial idea is a treadmill-mounted device that displays the current heart rate and at least some sort of min/max display, indicating when you are in the ideal HR zone. I think I know how to build the device, but the first step of intercepting the pulses has got me stumped. Anybody know the specifications of the strap and how to get the signal? Thanks!

Question by dmeierhofer   |  last reply


can i use piezoresistive fabric sensors to measure pressure exerted by backpack straps on shoulders?

I want to measure pressure exerted by backpack straps on shoulders. Will piezoresistive fabric sensors serve my purpose?

Question by swetambri   |  last reply


How do you braid illustration on the cover of "Leather Braiding"-by Bud Grant?

On the cover of the book "Leather Braiding" by Bud Grant it shows what appears to be a six strap flat braid with a two strap braid going down the middle.How do you do that??I do not see that braid anywhere else in the book.It pisses me off cause that's why i got the book!!Thanx for any help or clues.

Question by itchman   |  last reply


Is there a difference between a 1/4 inch x 20 bolt and 1/4x2 bolt?

I'm trying to make a camera neck strap using parcord and one of these bolts.

Topic by LAPIII   |  last reply


running a marathon with a camcorder-How to??

Can i mount a camcorder on my shoulder with straps (or duct tape)  and run 26.2 miles through beautiful mountain ranges.  Hands must be free. Any suggestions?!

Question by swieckert   |  last reply


EL Wire and Paper watch!

Just thought of this! Has anyone ever tried to make a watch/clock using el wire? I thought of making a simple 7 seg led design with a paper (this modeling plasitc) cover/strap as a wrist watch... Get the insides of a 7 seg type led watch. Use electroluminescentwires instead of segments. Put the wires bhind a paper face which is designed as a single piece with strap. attach battery. BINGO! Only thing I've not been able to verify - need to use an el inverter for the display Anyone had any dealsing with this technology and can tell me about it.. meanwhile I'lll scour the instructables Thanks

Question by sParekh   |  last reply


EITHER: How to make 'continuous heart pulse monitor'? OR: how to capture ECG from chest strap?

Greetings, What I am interested in is a ‘continuous heart pulse monitor’ so that I can plug that into (possibly) an arduino to drive a EECP machine. EECP machines run around $30k. So I’ll have to jigger up one myself. Usually I program in HotBasic. I am now learning ‘C’ programming language, via “Arduino in action” eBook, and sparkfun arduino Uno kit. I could sure use some help, like: Should I just buy a ‘chest strap heart rate monitor’, (Polar, or Motorola, or what)? Are there any units out there that can plug directly into a usb? Or do I need to get into wireless or bluetooth? Is a chest strap monitor more accurate than a finger or ear monitor. Should I be connecting to a laptop vs arduino? As you can see I am just beginning. Any help you can give me will surely be appreciated. Thanks for your help...Vernon 

Question by vmars316   |  last reply


3D printing replacement parts? Answered

Recently one of the plastic clips that connect the strap to the mask for my CPAP machine broke.  They sell replacement clips for the heargear ( 8 bucks for 2 clips).  My question is would it be cost effective to get replacement clips 3D printed, or am I better off just buying the replacement clips?

Question by Lorddrake   |  last reply


Steampunk Watch? Answered

I'm looking for advice and input into my (hopefuly) future project, a Steampunk style wristwatch. I'm wodering if anyone has any ideas for building a strap, be it made of leather or wire. Also, any opinions on how to "Steampunk" the watch face would be helpfull. I (sadly) lack the creativity needed to properly formulate an idea on how to make this and would very much apreciate it if a kind creator would offer their ideas. Thank you.

Question by prototype2213   |  last reply


Widow Maker 1.0 Vibra-Bots

Widow maker 1.0This Vibra bot is based on a wireless battery powered movement sensor light.The vibrating motor has been wired directly into the LeD array allowing it to autonomously react to different light levels and motion.Basically it will vibrate, move and light up its LeD's when ever someone walks past it.It can be very creepy when your not aware it's sitting in the corner, in the dark.If your wondering about the name, check the pen butane torch strapped to it.

Topic by Lftndbt   |  last reply


can i fix the tip of my soldering iron

I have this soldering iron that i totaly messed up. i didnt treet it well when i first got it and now i want to kno if it is even fixable. the tip is not only flat but the only part of it that is able to melt the solder is the size of a pin. im cash strapped and want to kno if there is some way short of buying a new tip to not only make it be able to melt the solder but to some how get it to be somewhat of pointed again. thanx

Topic by lurkingshaddow   |  last reply


How do I ground myself from static? Answered

I'm thinking about building my own custom PC but I need to ground myself to protect it from ESD. I can't buy a anti-static wrist strap because I don't know anywhere that sells them and I don't want to purchase it online. I've heard that if you're power supply is plugged in and off that you can touch the edge of the case (the power supply is already mounted). Is this true? Please reply. Thanks.

Question by awang8   |  last reply


How to build your own soccer/football referee communication system?

Hi, if you are a soccer/football fan, then you have seen soccer referees in UEFA, EPL, and World Cup matches wearing and using a communication system to talk with one another. An example of this is here: http://www.crescentcomms.com/ A similar system is offered specifically for dental offices: here (NOTE: actual that website shows a lot of interesting equipment) The problems associated with this system are: -Too expensive -Too many wires -Too many pieces of equipment -Too heavy to wear (a transmitter is strapped to your shorts as you run around) -Uncomfortable to use as you are running and sweating People can build their own cheaper systems by buying 2-way walkie talkies, headsets, batteries, arm straps, etc. off the shelves.  But it retains all the drawbacks. What I really envision are the following: -Secure communication (i.e. set channel/frequency) for at least 4 referees -Open communication (i.e. no need to push to talk) -Each referee wears a bluetooth headset like this one made by Platronics -Adjustable ear pieces as needed -Need to work for at least three hours straight at one time -Ideally powered by small lithium batteries (like those used for watches) -Ideally power source should be rechargeable or somehow be able to plug into USB or outlet for recharging As you can see, I really would like to see something built that can eliminate the wires, the weight, and discomfort.  Keep it super simple to use and equip.  If anyone has suggestions, please offer them. 

Question by shl_junk   |  last reply


My strobe light has a problem....

I have a miniature strobe light that I salvaged from a crappy Halloween decoration. I was planning on strapping it to my bike, just as an added accessory. Anyway, it worked fine, then is started being faulty. Now, it does not want to flash at all. It isn't charging the capacitor, so there is a problem somewhere before there. The strobe light has a cool option of either holding down a button or using an on/off switch. I cannot find any loose wires or shorts. Is there a way to tell if the flasher is broken? It hasn't been dropped, so I don't guess that that would be the problem. Any help would sure be appreciated!

Topic by Bran   |  last reply


Electomagnetic help!!! How to build a small electromagnet that holds 20-25 pounds?

I want to build an electromagnet that holds 15-25 pounds but is small enough to strap three of them on my forearm. Because it will be on my body, I want to make the magnet in a way that won't be very hot. I'm kinda a noob at this kind of thing, so please be specific!!! Also, would a doughnut shaped electromagnet work? If you have any questions or anything that needs to be clarified, please comment and I'll try to explain in greater detail. If you've read this far, thank you so much, and please help!!!! God bless

Question by LanceS30   |  last reply


using a thermoelectric cooler for High powered LEDs

Has anyone tried using a thermoelectric cooler, like this one http://www.allelectronics.com/cgi-bin/category.cgi?item=PJT-7to cool down a high powered LED star. I am considering mounting one on the back of a new Luxeon RebelI plan on ramping the current up to max (1 amp) on the led, and run the Thermoelectric cooler (TEC) as high as possible off a lead-acid battery. Strap a giant heat sink on it (maybe a fan too) plus thermal and silicone over the whole thing. It wouldn't be pretty, but it would be a neat experiment on how many lumens you could crank out of one of these things. Any inputs, suggestions, Ideas? Feel free to make an instructale on this if you want, I can't guarantee I will do it anytime soon.

Topic by John Culbertson   |  last reply


Good Gauntlet Ideas

Hey guys! So, I've been going around, and trying to figure out exactly what my next project is going to be. I want to make a gauntlet. Whatever I make, it has to be a gauntlet of a sort. Preferably a cool tech idea, or a weapon, but any ideas help. I have an old strap made for an arm gauntlet. I didn't measure it, but it is roughly an inch and a half thick, possibly two. I have multiple altoids tins, a pair of busted headphones (everything but the auxiliary cord is there, but the wiring needs some tlc), a lot of small dc motors, rubber bands, some old cell phones, and some odds and ends. I prefer not to purchase anything if possible, just make it. As real as possible for any weapon ideas (like, if it is a launcher, it should penetrate a box, if not more). Thanks everyone!

Topic by awsomebrawler3   |  last reply


How do I build a computer desktop tower carrying case?

I'm looking to build a computer desktop tower carrying case. I'm in a situation where I need to move from house to house each week and I need to move my desktop tower as well. I've looked all over the internet to try to find a "case" for my case, but I can't find one for a reasonable price. (ie. $100+) Basically what I'm looking for is a basic box with some straps and padding that I can set my case into and not have to worry about it getting banged up while I transport it. Any ideas or help for building something like this would be greatly appreciated The size of my tower is listed below if that will help. 18.30" x 8.10" x 18.00"

Question by djeffress   |  last reply


I would like to build a portable mini pc for games...any advices?

Being fed up with the various android portable units with ARM and whatnot,i decided that maybe i could build my own portable mini pc for gaming.not super-late recent intensive gaming,but like 5\6 years ago games,and of course emulators. so my idea is to strap one of those mini pc like beelink,minix neo etc to the back of my ipega 9023 joypad this thing here : http://img.dxcdn.com/productimages/sku_337604_1.jpg so what i need is an external display,roughly the size of a medium prize tablet,and of course, i need to know how to power the thing with a battery or similar. any idea\ advices? would a ups be a good substitute for a battery/powerpack?

Question by AlessandroP47   |  last reply


Camera not turning on, how can I find the problem?

A friend of mine dropped her Nikon Coolpix point and shoot, which broke caused a lens error. She handed me a ziplock bag with it disassembled and half the screws stripped and asked me to fix it, since her warranty ran out. I found and fixed what was causing the lens error, but the camera won't turn on. I didn't think to check if it powered up before I started, but I'd like to fix it if at all possible. I didn't do anything that would obviously cause this problem - I used an anti-static strap, was careful with the parts I took out, and all my work was on the lens part of the camera. The battery is charged - I have the same camera and it works in mine. I tried plugging it into a computer, no luck. What might be some possible causes, and how can I test for them? 

Question by applesnacks   |  last reply


How to run 5m intelligent LED strip via battery pack (portable power)?

Hello - I would like to apply this (or similar) LED strip to a costume: http://www.ecolightled.com/product/rl_hk_drgb_kit_2/digital_rgb_ribbon Is there a way to run this via battery power? It needs to be 6 lbs. or under, so it can be strapped underneath a garment. I've looked at soooo many types of portable power sources & battery packs now, I'm thoroughly confused as to how to determine power needs if I want this to run 4-5 hours (at least). Some battery packs seem like they might run it for a while, but I am not sure of how to make a connection properly (and what kind of connectors I need), and risk the battery exploding. I will be wearing this, so safety is an issue. Am I dreaming, or is this possible? Please help, and thanks! Also, cost is an issue... the cheaper the better!

Question by costumediva   |  last reply


Old Laptop----> Digital Photo Frame

This is an idea for a craft project: I'd like to have a digital photo frame, but I just can't bring myself to pay $200 for one. Now, I've got an old laptop sitting around the house that is slower than frozen mollasses, but has a nice big LCD screen goin' for it. It could definitely handle a photo slideshow. It's just a question of changing the laptop physically so it will hang on the wall and look nice-- remove all the unecessary stuff and strap what you still need to the back of the LCD and voila! I've had this idea for a while now, but there's no way in heck I have enough technical expertise to pull it off. So, I'm puttin' it out there to all you people who are smarter than me. One of yall is bound to be smart enough to pull it off. And then the rest of us will follow in your footsteps-- stand on your shoulders as it were-- and turn our old, crappy, laptops into nifty new peices of gadgety wall art.

Topic by Ke11iente   |  last reply


Building integrated led rear mountain bike lights?

Hi folks ,as said above , would like to install a row of red high-power leds into the rear of my bike seat  post to give a hidden , high-tech look  :-). Elements of design to be considered ;  to run off  2-4 AA batteries , to use 5-7  5mm leds , to use        " off the shelf parts " , no hand built electronics , to have constant and flash modes , would consider adapting an existing product ( e.g. cateye light unit ) For the installation i intend to drill a row of 5.5mm holes , 25mm apart , with the led heads sealed in place just protruding the surface of the metal post. The led leads would be drawn up and out of the top of the seat post into the saddle area and is where the battery pack would be strapped in. Any electronics could be housed inside seat post or under saddle. A handle bar switch would be nice but not essential. I feel confident about the wiring and fitting of the components ( electrician by trade ) just need a pointer with the electronics. Cheers Pete.

Question by biff55   |  last reply


GoPro Scuba Cylinder Mount

Hi there, I'm new here. I've recently found an entry-level 3D online modelling software, Tinkercad and have been Tinkering ever since. I'm into scuba diving and I've long wanted to design a GoPro mount for the cylinder to give a 3rd person view of me while I'm swimming about enjoying life underwater. (Think a less-sexy Lara Croft!) I wanted to run it past you guys to see what you think. I've attached 2 screenshots, because as you can see, the mount I've designed is collapsible, to save space in my GoPro bag. I've done the maths (Pythag) so each side is perfectly lengthed to create a right-angled triangle, with the hypotaneuse (long edge) is facing down my body, towards my feet, so that the camera view won't be obstructed. I've used a Pythag triple, so the arms measure 3", 4", 5". This was done for 2 reasons: a) It was easier to desine using these measurements and b) I don't want it sticking too far up from my cylinder so that it doesn't catch on wildlife/coral/divers. As this is my first GoPro mount that I've designed, I've had to go on deimensions I've found online for the actual hinges. I've settled on approx 3mm for each prong as well as the gap in between. I have actually shaved off .25mm from the middle prong of the 3-pronged-hinge, and left the 2-pronged-hinge at 3mm for the gap and prongs. I'm going to get the pieces 3D-printed by a local service I've found on 3DHubs.com, either in ABS plastic or in resin, though I'll probably go for ABS as it seems to be a bit more hard-wearing, even if it's not so detailed. In terms of mounting it to the tank, I will use 2 headstraps, with the over-the-top strap removed from each one and glue the plastic bits of each of them together, at the correct length of course. I would join them using a seperate piece of plastic and either a hot glue gun, superglue or even some sort of epoxy, whatever lasts longest in prolonged exposure to seawater. I would probably place it nearer the top of the tank, near to where the strap of the BCD jacket goes round it. Does anybody have any advice for me in terms of the design from a functional point of view as well as from whether they think it would actually get a good shot on the camera please? I look forward to your feedback, good or bad!

Topic by JackIsted   |  last reply


Cheap Compact tripod Answered

Ok, so I have asked a question like this before, but I never did get a compact tripod, and i am going on a trip in a few weeks and could really use the tripod. So I'm going to ask this again, but a little differently I need a tripod, preferably; Less then 16" when folded. I'd very much like 14" or even 12" if possible Extends to 50" minimum. Preferably >52" Costs less then $50, around $35 Weight is not really an issue, but lightness helps :) I am going to be sticking it in like the waterbottle holder on a bag- maybe a clip or something so i could hook it to the strap Stability is not a huge issue, as I am only putting an FZ100 on it (19.9 oz), so it doesnt need to support a DSLR, just a heavier P&S-; I do plan on some longer exposure shots however I think thats it... I do feel kind of sorry asking this question, but I really dont have the time or resources to find this completely on my own, and I am asking for a pretty strict set of rules. Thank you all so much in advance- Sincerely, A907

Question by astroboy907   |  last reply


Steampunk wrist-mounted scrolling map

Found this at Boing BoingOver on Boing Boing Gadgets, our John spotted this vintage wrist-mounted scrolling map from 1927, an antediluvian wrist-mounted GPS: At first glance, this 1927 map watch is pretty nifty: an antediluvian GPS, don't you know. It was called the Plus Four Wristlet Route Indicator, a name so clunky, unmemorable and artless that it even sounds like the name of a modern GPS device. The idea was simple: the Wooster-esque motorist would putter around England, scrolling a tiny paper map loaded in his wrist as he went with two black knobs. If you took a turn, you simple slid out one map and inserted another one and continued on your way. What ho! Ingenious! Except a complete road map only cost a few pence back in 1927, where as this device would have set you back around 5 quid. And just like modern GPS map providers, the real business model was in selling you additional maps. Which leaves the design. I quite like it: it's cheap, but whimsical and adventurous, like something you might strap on your wrist to traverse Oz. LinkLooks pretty cool and steampunkish. I would love to have one.

Topic by laminterious   |  last reply


Eyeclops night vision 2 review

              I haven't used the eyeclops night vision 1, so I can't make any comparisons. From the photographs, you can see two sets of lights on either side and a ring of leds around the camera lens. When in low power or "stealth" mode, only the lights on the sides are on. In the dark, the glow very dimly, you have to be 3 feet or less to see  them glow and it's still very dim. When in long range mode, the lights on the sides turn off, replaced by the circle of lights in the middle. These are clearly visible at close range, even in daytime, although still with less intensity as a red led. The knob toward the eyepiece is for adjustment of eye. I don't see what it does. The knob on the end near the camera adjusts focus. Seeing things at long range clearly and close range clearly require different adjustments. It's real infrared technology. You can switch between "military" and "spy" The difference between "military" and "spy isn't much. One of them is normal, infrared vision, and the other applies a green layer, making it seem like the view from COD. The 6 knobs along the middle don't do anything.  It uses 7.5 volts using 5 AA batteries. There there is only one LCD, despite it claiming dual LCD technology. The skirt on the eyepiece is detachable. The strap feels pretty cheap, I plan on making it into a head light sort of thing later with paracord or elastics. Objects appear closer and you have no peripheral vision though. The latter problem is something all night vision goggles have. Overall, it's not a bad deal for a $50 toy. The most annyoing thing is that the dials are a bit loose, so running or shaking them makes a rattling sound, giving away your position if you were doing covert sneaking around or playing a prank.        This is useful for scanning an area in the dark without revealing your location. It's also useful for night spying. What this toy cannot do is read words or anything in detail the size of words. Although navigation is possible, the lack or peripheral vision is a problem. Possible Mods: Add an airsoft or rc car battery to replace the 5 AA batteries. The half near the eye piece can be cut off I think. You would have to add a new compartment for the batteries though and the light from the LCD would leak out. I would add a strap of two so you can use it hands free. I would also attach a smal telescope or lens backward so objects appear normal distance. The peripheral vision problem could hypothetically be solved the same way people make DIY fisheye lenses. Extra infrared LEDs flashlights and other lights could be added around a house, allowing you to cover up the lights, not exposing your position. Another idea is infrared led throwies. They would function like NATO infrared glow sticks, allowing people to track a certain target or where to fire.

Topic by starwing123   |  last reply


Potenco's Latest Pull-Cord Power Generator - Wired Video

Check out Potenco's latest pull-cord generator in this interview Colin did for Wired. Video: Potenco's Latest Pull-Cord Power GeneratorA couple of weeks ago, we headed out to Potenco's amazing headquarters at the decommissioned Alameda Naval Base to check out their power generator for the developing world.It looks a bit like a yo-yo, and generates an average of 25 watts of power in normal operation. That's enough to power twenty minutes of cellphone talk time with just one minute of pulling.Their engineering feats could ultimately enable millions in the developing world to access information through their cellphones and internet devices, and light their homes with smoke-free lanterns. Now all they have to do is get them out into the field.One proprietary thing we couldn't show you was the Potenco cord testing room, where a Rube-Goldberg looking machine put dozens of types of strings through thousands of simulated yanks and pulls.Nicholson Baker envisioned such a machine in his book, The Mezzanine, but for shoelaces, not power generators. We echo his thoughts on the relationship between finding the right strings and civilization's advance: "He had constructed a machine and strapped hundreds of shoelaces of all kinds into it, wearing them down over and over, in a passionate effort to get some subtler idea of the forces at work... Progress was being made. Someone was looking into the problem."Enjoy the video! Thanks to Potenco (especially Mike Lin and Colin Bulthaup) for letting us come out and Michael Lennon and Annaliza Savage here at Wired for putting it together.

Topic by ewilhelm   |  last reply


Hub motorized 4 wheel drive wireless electric skateboard kit  

Landwheel drive is the newest drive system for skateboards that can be mounted under any deck. Just unscrew your rear truck and replace it with the landwheel Drive .    Specification of Landwheel Skateboard Drive:   Model Landwheel Drive( Dual Brushless in-wheel motors) Distance 20km Power 2 X 1100W Max load: 120kg Max Grade 20% Waterproof Water and dust proof (IP65) Frame Material Aluminum alloy + ABS Battery Li-Poly batteries Range 12-15km Weight 3.2kg (Include Battery) Size: 313 x 174 x 41 mm Certificate CE, FCC, RoHs, MSDS, UN38.3     Details of electric skateboard drive : 1. The Motors Two in-wheel motors Power 2* 1100w  Topspeed  35km/h Maximum Grade 20% Water and dust proof (IP65) Freewheeling when you push Exchangeable wheels 2.The Frame Solid magnesium single frame Click-in mechanism for the battery   3. The Battery Pack Range 12-15km Charge 2-4hours Weight 700g        Energy 94.08Wh    Capacity 3200mah Swappable via click-in mechanism Certified for airtravel Water and dust proof (IP54)   4. The Remote One button device Switch between 2 riding modes LED displaying state of charge Rubber coated for better grip Safety wrist strap

Topic by Hollie hua 


Extending a mobile phone's camera away from the phone by adding some longer cable?

I have a little project where I am looking to extend the mobile phone's camera a few meters away from the phone while still being able to use the phone as a viewer. I would like to use the camera and the phone because the power source is already set up, the camera and the phone mesh without trying to add a camera to a small LCD screen, and I have loads of old mobile phones and was hoping to be able to recycle one or two of them. I would like be able to place the camera of the phone a meter or two away and be able to view the video on the phone. This could be useful in looking in hard to reach places within reason. I could also maybe set up a little rig for attaching the camera to my motorbike helmet and recording without strapping the entire phone to my helmet. This could also maybe be used for making a little rear view camera for my bike by placing the phone on my handlebars and routing the camera behind me. I know they sell back up cameras, but again I am just looking to find a use for my mountain of phones. I assume I would just need to find the camera's cables and extend them, but I am also going to assume they use a ribbon cable. I was just wondering if anyone knew of a way to extend the camera away with a bit of wire soldering or something along that nature. Would the mobile phones with VGA cameras use a system other than ribbon cable? Hopefully someone can wrap their head around what I am describing and help out so I can find something useful do something with a few of these outdated mobile phones!

Question by FishstiK   |  last reply


Help with trying to make an Arduino-powered MIDI keyboard-controlled ferrofluid pattern-making exhibit!

Hi guys, apologies for the long title. As it says, I'm trying to create a science exhibit that best explains a scientific phenomenon, while being fun and user-friendly. In this case, electromagnetism. Essentially, I want to hook a MIDI keyboard to a USB host shield on a Duemilanove I have lying around. The arduino reads those inputs, and outputs a designated pattern or single pin current to some electromagnets strapped under a tank of ferrofluid. When someone comes by and plonks on the keyboard, pretty patterns SHOULD HOPEFULLY rise and fall in the tank. Attached is a diagram for easier explanation. I have a couple of issues, though. 1. The arduino coding, which I haven't started with. A quick google search returned a post from Circuits@Home, where Colin from MAKE uses a modified PS3 script to recognise USB MIDI inputs. http://www.circuitsathome.com/mcu/interfacing-midi-devices-with-arduino-using-usb-host-shield This is my first real Arduino project. I've only tinkered with the I/O before this, nothing major. 2. A Duemilanove can only output 0.2 watts from a single pin (correct me if I'm wrong). Is this enough to drive a reasonably strong electromagnet? Are there some conditions I need to fulfil? Number of coils, materials for the core, etc. 3. I plan to make the ferrofluid with vegetable oil and toner. Will any old oil and toner do? Most websites come up with a specific variety, but that model usually isn't available in my area. I don't understand toner nomenclature at all lol. 4. Is it possible to wire/program the Arduino to allow a small speaker/synth to output sound, while having the current to power a set of electromagnets? I expect there to be about 12. That's all for now. I'll update if I make any discoveries/progress! Thanks so much!

Topic by cwong14   |  last reply


Best motor suited for a diy generator that can provide 48V?

Ok, out of all places, I've seen this particular question be asked once and the discussion trailed off topic somewhere. Before we start, Yes it's a bit of a backwards thought but it's still a project, experiment and I'd do it for the sake of doing it. I have an electric scooter - lack of knowledge for proper battery care during winter lead it to 4 dead batteries. In my area, as long as the scooter is moved by an electric motor and makes less than 40km/h it's a street legal and non insurance or license requiring vehicle. Only issue for me is the limit of the battery capacitance and the eventual depreciation of the battery capacity. So I want to try an experiment of strapping a small weedwacker motor or even a hobby airplane fuel motor to an electric motor to act as a power source for the scooter. Don't laugh, It's an experiment. Yes, I'm aware I can just buy batteries. they are 50 bucks a battery + 12 bucks shipping and mine ran on 4x of these suckers. Buying batteries would work but would not satisfy the curiosity of an experiment.. Now then: ============================================== My scooter, when bought, could do about 12 blocks (1 block = 2km ) trip on a full charge. Before this winter, it could do 8 barely. It ran on 4x Lead Acid 12v 18Ah batteries. Now the batteries are connected in series so that's 4x 12v 18Ah making it 48v 18Ah. At this point we can drop the need to have the generator produce exactly 18Ah of current because that originally is the total battery capacitance, determining how long we can ride before draining of the batteries. So with a generator, all we need is to draw sufficient Current at the moment of generation. Which motors are best suited for generating 48v. I'm obviously missing some que variables here but I just want a point in the right direction. I'll most likely need extra head room and make a Step Down Buck Converter. Every time A talk of a diy generator comes up, people seem to mention Stepper motors. Seem like good choices? Brush-less, multi lead motors, yes - no?

Question by MilesT9   |  last reply


500 Lb Thrust small jet engine? Answered

So the fun and crazy side of me has come out again and I have thought up some crazy plans for a jet powered wing suit.  I'm sure many of you have seen the swedish rocket man, he jumps out of planes with a small wing and 4 miniature jets strapped to his back.  That is cool and all, but I would like to look at building something a little more useful than fun, although I could imagine it would be a blast.  The idea is to design a large wing 8-12 feet.  It will be made extremely light, however extremely strong because the wing should be able to handle strong g-forces, tight turns along with possible above mach speeds (probably pushing the boundaries of sanity.  This will probably require a carbon fiber and aluminum structure while requiring a rigid wing surface as apposed to the lighter plasticy flexible covering used by smaller aircraft.  This wing will be able to take off and land, eliminating the requirement of a plane to haul it up and then also not necessarily requiring a parachute (one will be worn at all times)  The wing I imagine will not be any lower that hip height and will also have a v-tail for more control.  Now my question is if anyone knows of a small jet engine that exists and would fit this project,  It would also be possible to fit two, one on the underside of each side.  I am looking for 500 to 1000 lbs of thrust and they need to be very small, and lightweight.  Do any engines of this type exist.  I also may be out of my mind expecting to take off with that amount of thrust,  I just don't imagine the whole thing to weigh more than 200 lbs plus me weighing just under 200 lbs.  So 500 would ideally allow for vertical take off, however it would probably not be practical.  Would an engine with this amount of thrust be suitable for my needs or would I need 1000 to 1500 lbs of thrust.  One big goal is for the wing to be very efficient so I don't want to be wasting fuel, however it would be nice to be able to fly quickly for some local entertainment.  Maybe I would throw on some solar panels for the electronics as well. EDIT....... I found this http://jetbeetle.com/JB_body_products.htm This engine seems pretty substantial, would one or two of these be capable of doing what is needed here?

Question by jj.inc   |  last reply


Potentiometer/Variable resistor with AC advice

I'm a computer store tech who knows how to solder some(but DC stuff only) and who also enjoys cooking, so my ? is: What's the best choice of pot. for use with US household current to actually control the cooking temp of my hotplate? End result is to eliminate the annoying "heat spikes" you get due to lack of a pot. in the design, IE literally everything sold these days turns on at full current/temp until it reaches X temp, basically it's just temporally defined by how far you turn the knob, and your pancakes wind up crispy black around the edges and gooey in the middle  instead of golden brown and amazing all over. I want it to turn on at X current until X temp (like electric frypans/burners did if you're old enough to remember.) All I need to do ( I think) is add a pot/VR into my burner's element  "line" the right way, it already shuts off at X temp just fine. Incidentally, that's the "click" you hear when any home electric cooking device (sold in North America, at least) hits temp or turns on, the temp. control switch thingee connecting. It's NOT a VR/pot, just a pair of electrodes JUST barely touching strapped very tightly to some ceramic discs. It uses thermal expansion of the discs/electrodes to make things just a tiny bit bigger and separate the tiny little electrode spoons  But all that boring geekspeek affects in this configuration as basically just temporal heating, IE no reduction of the amount of heat in my frypan, just the cooking time. Science says if I reduce the amount of electrons flowing thru it just slightly as well,  it'll be colder but still hot and still shut off when it's hot enough. A pot/VR wired in the right way will do exactly that, won't it? After some research I'm thinking something like a 30-50K "B"-taper pot. wired with 2 of 3 traces (https://www.instructables.com/id/Wire-a-Potentiometer-as-a-Variable-Resistor/), I'm looking for a "broad" response range while turning with a tight  "pinch" effect at low end for amazing banana-brown-sugar-pinch-of-nutmeg pancakes with coffee on the tiny balcony/fire escape in the morning but I have no idea how the numbers work for AC currents. Does 120vAC mean a different pot or a diff config/approach altogether? Or should I be looking into AC variable resistors, instead? I know an awful lot about "base" science, enough to get me this far, right, but AC throws me for a loop a lot, and there's a gap in my knowledge/experience, between the basic stuff and how it applies to stuff like my application, I don't get a lot of the numbers/formulas and how to use them.  A VR would the ideal tool here, but they are hard to get in the right form with the electrical qualities I need, whereas pots are usually "turning switches", right?

Topic by MattH68   |  last reply


Making the pipboy/hitchhikers guide

I've been thinking about this for quite some time, unfortunately I don't have the economy to purchase a mini PC/PC mobile, let alone one powerful enough and with enough space for all the things that I have in mind for this gadget. Though there seems to be a lot of other people on this forum with the cash and possibly the motivation to complete this so I'll try and explain the idea for you. If you've ever read 'The hitchhikers guide to the galaxy' by Douglas Adams or played the new or the old Fallout games you'll have noticed that the common denominator is that in both instances they have nifty little pocket computers with all kinds of information and gadgets. Now I realize that it will be overkill for most people to have a mini Geiger-counter, a gas measuring device and a light sensor attached to it, not to mention to expensive. But it seems odd to me that some of the software options available isn't already included in mini PC's, such as: -Wiki-taxi which is an offline version of the entire Wikipedia. -As many search-able dictionaries as is practical. -A general library of PDF's that you find useful depending on where you are/are going to go, or maybe the PC you get your hands on has enough space to encompass a general library for the entire world like information about herbs, plants and animals in every region of the world Instructables for certain kinds of gourmet dishes for an example could come in handy while traveling the world, anything goes really . -Furthermore it could have stored maps of the entire world, of course not in "hair counting quality" but good enough to find your way if lost, then again some of these mini PC's have GPS built in but you will still need all the map packs for the different regions of the world. -One could add how-to videos of different things that might come in handy if traveling in poor countries or simply backpacking, like braiding and general hand crafting items to have something to sell. Or guides for learning to play a certain instrument and so forth. And so on, there's an endless supply of software one could put on a gadget like this, but that's just half the idea. The other half would be constructing some kind of housing that would allow a person to strap the computer sideways on ones arm so that it's always easily available like a normal wristwatch and preferably protected against shock and moisture/water, furthermore it would be nice to have extra slots in the housing for such things as a small LED flashlight and any kinds of other tools that would be practical for the person in question that makes this thing. This computer would of course need to have a rather big battery capacity as well, and if it has long lasting batteries then several more of the batteries can be incorporated into the housing allowing the user to switch between each of the extra batteries when the original one in the PC runs dry. For off-the-grid travel I'd believe a sufficiently large fold-able solar panel would suffice to charge the device, maybe it could be incorporated into a jacket or simply stored as a liner in the jacket. Now I don't know if this is all easily understandable so if anyone has any questions or maybe someone would even make this then please let me know as this idea is quite dear to me, do post any ideas or complaints as well, I welcome it all. Oh, and in case someone might be bothered by the extra weight this would put on (say your left arm) then simply make another housing for general tools that you can have on the right arm/wrist and balance the weight out so that after a while you wont notice it as your muscles naturally adjusts to the weight, would basically make you stronger in the process.

Topic by wolty   |  last reply


Detecting Very Slight Tendon Movements In Wrist

I've always had an intense fascination for lucid dreaming. Finding ways to communicate or control outside devices based off the slight body movements that are possible despite the natural paralysis during sleep is a topic of great interest to me. I have several LDs (lucid dreams) each night and through much experimentation have found that with a bit of concentration, I could move my fingers enough to trigger very sensitive buttons (if placed perfectly before falling asleep) or to grip myself (if my hand is placed say, near my neck before intentionally entering a dream from waking) such that the sensation of my fingers reaching my neck would wake me. These experiments were proof enough that if I perhaps had some sort of glove or wrist mounted piezo sensors that are able to detect the individual tendon/finger movements with high enough sensitivity, combined with software that can parse patterns and reliably filter out minor unintentional simultaneous movements for the fingers that are prone to movement when others nearby are moved, it would be possible to establish one way communication with outside devices, the Internet, etc. Input could be in the form of different patterns or even text (tap code, morse code, or through a hybrid allowing use of each digit of the hands) or musical notes (each finger representing a note of a scale with a finger or two used to change octave or to toggle sustain.) As a musician who "writes" his best music within his dreams, this could be quite handy for getting melodies down before they vanish from memory on waking. For example, to activate input, you could perform a simple pattern that is unlikely to be triggered unintentionally. It could be as easy as left thumb flex, right thumb flex repeated in that order several times. From this point, you could use another pattern to choose to trigger an alarm (sound, vibration or electrical shock), or to initiate musical or text recording. There are many different uses that could be explored, and it might even be possible that 2 way communication could be established if a reliable method of transmitting to the dreamer without waking them could be created. This is however beyond the scope of my intentions. I have suffered from sleep paralysis on a nightly basis for over a decade now which can be extremely frightening and last up to several minutes, and during this time I am able to move my fingers as well as shake my head back and forth (which I need to do to break out otherwise the paralysis will persist until I'm pulled into a nightmare.) My solution to these terrifying experiences was wearing a heart rate monitor with an alarm that goes off past a certain BPM, which only happens when I am frightened. Now that I am so used to these experiences, my heart rate does not increase enough that I can reliably use it as a trigger without also waking myself out of exciting dreams that I'd rather not have prematurely terminated. I am fairly confident that a device such as this could help with breaking out of my paralysis at will and PERHAPS even be sold commercially to other sufferers of this condition, however niche the market. Giving me control over my sleep paralysis alone would be a highly satisfactory result with significant quality of life improvements and be worth the effort of building this. Waking up partners in bed with my head thrashing is less than ideal! As an avid software programmer, I do not think that the code involved would be terribly difficult. However, I have very little electrical knowledge and building this without existing plans would be tough and time consuming. It would be enough to have a pressure/flex voltage for each digit transmitted to a Raspberry Pi or via Bluetooth to a computer and the rest could be done through software. My questions are.. Does a commercial device exist that would be suitable for my purposes and not be terribly expensive? Perhaps a glove? Is a wrist strap with piezo sensors over each tendon that control the fingers a realistic possibility to achieve my goals? I do not need to know the position of the fingers or whether it is pushing against something. Just that movement is being attempted. Do existing plans exist to create a similar device? Thank you!

Question by Ril900   |  last reply


QUICK: Ideas for getting drone out of tree! [EDIT: already got it down, but ideas are welcome!]

Ok, so I have built up my $400 FPV quadcopter, and just last night, I was able to get it in the air working flawlessly! I then proceeded to have fun with FPV on a small TV monitor. I quickly got the hang of it, and decided to venture up and around the back yard. However, there was one problem I have been neglecting, which of course, it bit my ass as you can tell from the title. From countless hours of debugging and stress-testing previous weeks to find the intermittent issue with the ESCs, I finally pinned down the issue and was able to reprogram the ESCs, as well as calibrate them properly. (turned out when I first built the quad many moones ago, I unknowingly entered programming mode in the past and changed stuff I had no intention to change!) So eventually, I punctured one of the cells on the battery, and did not realize until a few days ago. I found after close inspection that it was most likely due to a crash which dislodged the battery from the strap, and it scraped up against the video transmitter shielding and heatsink. I removed and discarded the damaged cell, so I was left with a 2S battery. It is BARELY enough to lift the quad. And very slowly at that. However, I could not wait for the new battery to come! I just HAD to fly it to see if I got it to work! :D So today, I have been practicing full-on FPV, and unknowingly flew above a tree. I thought I was next to our chicken house,  and was looking directly at it, hoping to land directly in front of it. However, I did not know I was as close as I was to the tree directly below me. By the time I saw it it in the mobius camera, a slammed the throttle as high as possible, but by that time it was too late. That stupid 2S battery that I have not bothered to replace just did not have the umph to pop the quad up into the air higher, and as it discharged to below 6.98V based on the video feedback data, and the quad just kept descending even at full throttle due to the voltage being too low to effectively power the motors. So there it went tumbling and got snagged on to a thin limb. I lost remote control, so I could not get it unstuck like I did before from a previous flight. But I still surprisingly had FPV working, with the minimOSD sending down GPS data and battery voltage level. So I get to watch the battery voltage trickle down 1 mv at at time. (Welp, time to pop the kettlecorn and watch the 2S battery progressively deep-discharge and get more damaged by the minute!) It did, however, rise back up to 7.4V unloaded (telling me that the internal resistance must be pretty high, so I would not to too bothered too much to throw away the 2S battery entirely!)  Nor did I bother to watch it to see how low and how long it will take to discharge below the safe limit. I packed up all monitor and ground gear to get it out of the cold. So here it stands; stuck real high. I have tried climbing up 14-18 feet onto the tree, but it was still a good 12 feet up. I tried a rope to the trunk and shook the hell out of the tree. The limb that the quad was stuck on did not move much, and the tree was dampening the vibrations too much, even after hitting a resonance peak (technically a harmonic of the resonant frequency), where I could clearly see 2 "standing waves" in the trunk, but that got tiring real quick,and the winter sun has set and things were getting darker by the minute. I did not budge the quad.  I eventually resorted to shooting the limb with a 22 rifle, and on the 3rd shot, I got it to fall down!!! .......... 3 feet, that is, until it got stuck on an even LARGER branch, and now it is really stuck on it. It is on its side on a small fork in the tree, and it is snagged on that now. I can't shoot the base of the branch to break it, because it is like 4 inches in diameter, and on the forked branch right where it is caught, the quadcopter is sitting directly on! If I shoot it, there is a good chance of hitting the quadcopter and destroying the lipo battery causing it to catch fire, or hit electronics or the camera with the beautiful 1080p HD footage of the crash! Again, shaking the tree violently does not do much to budge it. Perhaps someone in the community has an idea on how to knock it down? 

Question by -max-   |  last reply