Passive Amplifier Optimized for a Single Frequency

First off, I know next to nothing about acoustics or sound science of any kind.  My idea is to make some sort of passive amplifier, like a horn, that is optimized for a single frequency, I'm thinking about 4KHz.  I have no clue how to go about designing such a thing and all the info I found on google was too complicated for me to understand.  Does anyone has any starting points for me or just general advice/suggestions?  Or, if you're feeling generous and/or really bored, would anyone like to design such a thing for me? Thanks ~Josh

Topic by Josh_Blackburn 


Laptop powerbank 12v to 20v and upto 5A output using 18650 batteries with USB 5v added

Hello ladies and gentlemen.  Im looking into buying a laptop powerbank charger for my Lenovo X1 carbon that charges at 20v 4.5A 90w fast charge with upto 80% charge in 1hr. But it will also charge at 65w and maybe 45w I've read. But this will not give me the full power of the processors and gpu etc. Unless I charge at 90w 4.53A  there are are some powerbank that are around £100-170 for sale but these don't give full 4.5A. Mainly around 2-3.5A so will maybe or maybe not charge she give me full power of the laptop   so I'm thinking about making me own using 18650 batteries. Good Samsung or LG 2500maH plus cells. Prob around 3000mah.  Im thinking I could either use a buck down or step up and use the batteries on series from 3S to 8S and then 3-4P to give me around 10000mah. I'm looking for the best efficient output so I'm not sure whether to use higher input or lower input to give me 20v.  Or or maybe I could go the inveter route using a 12-24v 150w inverter?? Efficiency is the main thing here. What is the best option do you think. Should I use 12v or 24v for max effecient conversion.  Ive searched the instructables for such devices but cannot seem to find anything like this. Or would I be better to buy one??? I would want to add USB and USB c also. Defo USB 2.0.  Could you you please help me choose and find the answers please?  I fancy the DIY route because I'm looking into solar and battery power storage and also boost my range wifi range through either ptp or directional attenna. These projects will come after the laptop powerbank.  Any my help would be appreciated a lot.  Kind regards.  Scott. 

Topic by ScottL190   |  last reply


Version 2 of the Instructables Plugin for WordPress is out now

I just finished up version 2 of the Instructables Plugin for WordPress https://wordpress.org/plugins/instructables/ This plugin allows you to list instructables as posts or tiles by username, keywords, groups, all recent or featured on your WordPress site. 

Topic by MrRedBeard 


What is your favourite movie?

Hi! What is your favourite movie of all time?? ~fritz707

Topic by fritz707    |  last reply


convert 240V 50Hz to 120V 60Hz

Recently I bought a Blender imported from US(to India) which runs on 120V 60Hz. I need a converter which Converts 240V 50Hz to 120V 60Hz. I got an idea of using a rectifier-inverter circuit such that by varying the gate signal can accomplish the aim. Is this idea a possible one?

Topic by ravic88   |  last reply


Can I add my Autodesk Screencast just like an Youtube video?

I create projects on software and document them on Instructables. But it's always better if I can make a recording of what I did, no matter how many screenshots I add. I use Autodesk Screencast for recording my desktop screen, but I can only add them as links which will take you to a different webpage. In simple words, they are not added like Youtube videos.  Is it possible to add Screencasts like I add as Youtube videos?

Topic by alamtania   |  last reply


Prototype for Business Sake!

I'm super excited to give a talk at Maker Faire this year! I hope you're able to make it! Talk Scope: Go from maker to entrepreneur by using prototyping tools to validate and build robust business models. Whether you have a dream of turning your hobby into a business or you’re interested in testing your innovative technology for commercial viability this talk is for you! VISIT HERE Background: As a Strategy Designer I work with clients to design relevant strategies and future business model options. I do this by providing teams with new tools, skills and mindset to stay competitive in today’s market. My company, Business Models Inc, is an international design and innovation strategy firm. We work across industries with large corporates, startups, and early stage entrepreneurs to help them develop innovative business models using our user-centered lean approach.

Topic by Carleyy   |  last reply


How do refrigerators work?

I've always wondered what keeps my beers cool and my cheeses fresh. Now I'm new to Instructables, but on the advice of a good friend, I thought I'd post this here:   I love to figure out, research, how stuff works. And then figure out how to tell that story. This one animation has a bit of a story itself, because it turns out I made the first version a bit too fast... I didn't do my research properly. Anyway, so here it is. I'm curious to know what you think!

Topic by Sebvandenbrink   |  last reply


Can any one identify these strange pliers?

I have been lent a pair of unusual pliers, and have found them to be incredibly useful for working with wire chains. I would like to buy a pair, but can not find anything that resembles them, so does anyone have any idea as to what these are called? Many thanks in advance!

Topic by ChrisM590   |  last reply


Small 2-stroke Turbocharger

I was wondering if any one had heard of attaching a small turbo charger to a lawn mower or weed whacker , if anyone has heard of it could you explain how, as i am anxious to try this with my recently salvaged 2 stroke and just see as much power i can suck from it.

Topic by firemanfu   |  last reply


Reusing desktop and laptop monitor CCFLs and power supplies to make a floodlight

I'm using a collection of broken laptop and desktop monitors I got free from a repair workshop to assemble a floodlight/spotlight from the CCFLs and their inverters. The desktop monitor power supplies take mains voltage (240 V) and power the CCFLs but also seem to provide a 5 V and 12 V supply to the electronics that control the LCD. The laptop inverters themselves accept either 5 V in some cases or 12 V in others so naturally I want to run the laptop inverters off the 12 V and 5 V supply because otherwise it's wasted. The problem is that I don't know how much power I can draw from the 5 V and 12 V of the power supply. I've had a look at the back of a monitor that says it draws 0.7 A at 240 V. What translates to 168 W which is more than I was expecting. Assuming that the four built-in CCFLs use 8 W each, that would still leave 136 W. Assuming the power supply is only 60% efficient that leaves (168 W x 60%) - (4 x 8 W) = ~68 W. I've no way to tell how that's distributed across the 12 V and 5 V but if it's 34 W each then I can draw 2.8 A from 12 V and 6.8 A from 5 V? I figure I can probably, maybe attach eight laptop inverters to each desktop PSU (four on 12 V (1.6 A) and four on 5 V (4 A)?

Topic by THX 1138 


The cost and downside of modern life

In another topic we noticed that times have have changed in terms of repairs, spare parts or just finding a replacement for something. It not only seems that a lot of people no longer bother to repair their broken things but also that for those who still want to the available options are disappearing fast. Take the common lawn mover as an example: We can buy them in dedicated shops, the local hardware store, supermarkets and sometimes even at Aldi. But if you need such a simple spare part like a fuel hose or gasket for the carby you are usually lost unless you can order the parts from some online store at the other end of the world. Electronics are even worse, here a broken charging plug or just loosing the charger can mean people throw it in the bin to buy a new device. Splicing a rope? Why bother if a big bunch of knots does the same LOL Do you still remember these little repair shops that used to fix your waching machine, TV or sometimes even your electric drill? Where are they now? Or all these small electronics shops selling resistors, wire and complete kits? I still remember the times when I could take my radio to the local shop, the guy listens to the sound and lack of available stations and knew right away what parts I needed - and they were right at hand. For a few bucks extra he even replaced the broken bits if he had the time. After thinking a bit about all this I came to realise two things: a) We are getting lazy and no longer learn vital skills because modern life makes us think we no longer need these skills. b) Unless you can repair something yourself, labour costs mean a repair is often not worth it. Who here, under the age of 30 still knows how to make a good campfire from scratch, dares to take the lawnmower apart to fix it himself or simply bothers to stich up a little rip in his fancy tent instead of buying a new one? For crying out loud, a lot of kids don't even know how operate a washing machine by the time the lease the parents home for good... Schools seem to support these life changes by no longer teaching the use of pen and pencil, not to mention ink... All the kids get is a tablet or laptop and that means they don't even have to learn the language anymore - that what the spell checker does. If I dare to spin this further by another 25 or so years I only see chaos. Everyone is highly specialised, noone bothers to cook anymore and the third generation in the family no longer has any clue what the first generation is talking about. When my grandfather grew up life was hard. When my parents grew up life was all about expressing yourself. When I grew up life was intersting because everything was changing so fast. When my kids leave the house what will they say about this?... What do you think ? How much has modern life affected since you grew up ? And of course: Do think it is the right trend ?

Topic by Downunder35m   |  last reply


Underwater Jetpack Project. [HELP NEEDED]

Im planning on making an underwater jetpack something like this. However I'm a bit to dumb to figure out all the ESC and electronic components of brush-less motor systems.   Im also limited because this is a school project and in order to be reimbursed the materials need to come from amazon.  I will be using it in a chlorinated pool for demonstration but salt water resistance would be nice.  My requirements are as follows:  1.  Propeller must be covered as I may do another project after this one that requires fingers (im thinking 6in diameter pvc pipe with chicken wire or a metal grill over the ends) 2. Modifiable for different circumstances.  (I already cut up an old backpack and screwed a plywood board to it for mounting the propellers and  batteries, however I may decide to go with hand or foot mounting instead.   3. A trigger operable switch. (Cordless drill style although I don't care that much about speed control.   I'm planning this project to be for a senior year high school project (next year) so I have plenty of time. Do you guys think something like this would work for the propellers?  Their for air so I would expect significantly reduced performance in water.  However if they are to high rpm/low torque to spin properly in water perhaps I could keep the enclosure and switch out the motors for higher torque ones.

Topic by TypeNameHere 


Free Rice Help End World Hunger

I found this website FreeRice.com that says "For each word you get right, we will donate 10 grains of rice through United Nations to help end world hunger"I thought this was pretty cool, all I did was use Dictionary.com to figure out the words.Any way to possibly "hack" this? To auto answer or something then leave it running ;-) (It would be for the good of the world, like a modern day Robin Hood or something?)

Topic by TheCheese9921   |  last reply


How can I convert a transmissive to a reflective LCD screen?

Hello everyone, So basically a reflective LCD screen is one that has no backlight, and reflects ambient light off a type of mirror reflector, to allow the image on the LCD to be seen via reflection. An example of a reflective LCD screen is the Gameboy Advance's LCD screen. A transmissive LCD is one that has a backlight that transmits light, but does not reflect light. These are typically 99.99% of the screens out there, such as PC Monitors, Smartphone screens, etc... Now I would like to know how to turn a Transmissive LCD screen, into a Reflective screen, like the GBA screen, without the need for a backlight. The reason I ask this is because I need it for outdoor use (to be sunlight readable), and backlights can't compete with the sun, and having a strong backlight drains battery. I have done a lot of research on this, but can't wrap my head around how the GBA screen works. I have removed the backlight off my computer LCD screen, and added a reflective film beneath the rear polarizer on the LCD screen, but it obviously doesn't make it reflective. I'm obviously missing a crucial step. Is the reflective film in the GBA, 'sandwhiched' somewhere in between the actual LCD screen? Does anyone know how to make a Transmissive LCD computer monitor, into a Gameboy Advance Reflective Screen?

Topic by davidwinst   |  last reply


Automatic Irrigation using d1 mini

Hi Everyone, I reviewed different automatic irrigation system projects here in instructables and other sites as well and i decided to gather parts to do a simple small project myself. One thing that comes hard is the programming part as I don't know any programming language. I'm looking for some help with code merging, explanation and some general guidance. Could you please let me know, point me to right direction and tell me what you think and if requirements are actually achievable? What I would like to achieve: Intention of this project is to have manual and auto irrigation system which will: 1. Measure soil moisture and dependently on the value activate the usb pump which will water the plant (preferably analog output that will show the measurements in %) 2. Manual activating the pump via hardware button and via mobile phone with internet connection 3. Distance sensor which should measure how much water is left in the tank 4. Email notification with info when to water the plants and soil sensor data regardless of the automatic process that has already started 5. Email notification with info about the water in the tank when it’s near empty 6. Dashboard preferably inside the network (not using third party like blynk or others) with access from the internet (I have QNAP that I think can be used). 7. If possible – have amazon echo (Alexa) read the sensor data to tell me the values and comment if the plant should or shouldn’t be watered or the tank should be refiled or not as well as ability to ask Alexa to start or stop the irrigation Hardware: D1 mini: https://wiki.wemos.cc/products:d1:d1_mini Wemos V2 Relay shield: http://hobbycomponents.com/shields/865-wemos-v2-relay-shield My relay is slightly modified: 2 small wires soldered to the vcc and ground so that when it receives the signal on d1 pin it opens and current flows to female usb connector supposedly activating the usb water pump. All this can be stacked together even with soldered wires YL-69 sensor: http://www.oddwires.com/yl-69-soil-hygrometer-humidity-soil-moisture-detection-sensor/ Ultrasonic Distance Sensor (HC-SR04): https://thepihut.com/products/ultrasonic-distance-sensor-hcsr04 USB mini water pump: www.goo.gl/yUABDd Button x4 if needed: Board x4 if needed: sample codes used in other projects: https://randomnerdtutorials.com/guide-for-soil-moisture-sensor-yl-69-or-hl-69-with-the-arduino/ https://create.arduino.cc/projecthub/nekhbet/using-the-yl-39-yl-69-soil-humidity-sensor-with-arduino-968268 https://community.blynk.cc/t/irrigation-relay-with-timer-esp8266-wip/700 Alexa enabled homemade cat feeder example: https://www.hackster.io/darian-johnson/alexa-powered-automated-cat-feeder-9416d4 Thank you very much in advance for your help and support.

Topic by wube   |  last reply


Spinner/fidget contest entrie

I am asking for some help, as I can not seem to enter my intructable into the fidget contest. I designed my spinner and published it today 7/8/2017 as an instructable, but it would not let me enter that specific contest. I could enter others. I went back into the instructions and as far as I can tell I did everything the way that it said I should. Any help would be appreciated. I manually added it to the contest but it has not shown up on the contest page, and it also now shows 2 instructables that I created that are the same. Thank you in advance for your help

Topic by DonW19   |  last reply


How should I improve my Instructables so that they get featured?

I started off quite well with Instructables. My Instructables were also featured. I was enjoying it a lot. Just when I thought that I'm understanding the platform and can contribute well to it, I was proved wrong.  From past few days, my Instructables were not featured and I'm wondering why? Am I not putting enough pictures? But I document each and every step! Am I making grammatical mistakes? But I check my drafts twice or sometimes thrice before publishing. Moreover, I use "Grammarly" which automatically detects the mistakes. Is the problem in my writing pattern? Well,  I don't write long paragraphs, I just make bullet points to make the steps easy to read and follow. Am I not providing enough steps? Apart from the usual steps, I also provide advanced steps for almost all my Instructables. Is the problem in the introduction or main image? I try my best to express my idea in the introduction and as for the images, I use the advanced Renders. Are my ideas not unique? But I search the website before working on an idea. Are they very simple to do? But, it's meant to be simple. It's basically for the beginners.  Well, I work on Fusion 360 and I only contribute to the Technology: Software channel as of now. Is this the problem? I feel that if I'm investing my time on a project, working so hard to document it and contributing to a community, that should be good enough. Else, is it even worth sharing? I have 20 Instructables now, of which only 13 are featured. Not every Instructable can be featured and I understand that but there must be something I'm not doing the right way. I'm seeking for some honest opinion here on how to improve my Instructables.

Topic by alamtania   |  last reply


Rewards for authors who follow up their instructables

Nearly every instructable I find interesting has dozens of questions at the bottom unanswered. Some of them are inane silly questions like "how much does this cost?" but others are quite often asking for help in finishing the instructable. It's difficult to enforce follow up on posts, but you could offer rewards in some way, even if it were a simple thumbs up/vote count system or something similar.

Topic by cosmicr   |  last reply


build-a-tank instructables contest!

Hi all you tankers out there! This contest is for people who love tanks and always dreamed of building their own! the 3 winners will be posted on my page! contest ends July 31st.

Topic by Lukethemonty   |  last reply


DIYers and makers, answer please!

I'm currently doing an internship in a portuguese company, whitesmith and I'm developing a tool that will hopefully help makers and DIYers and make your life way easier when you're starting to create something new and need a whole lot of materials. What I'd like you to tell me is what is the most boring step on the process of building something new. Would you consider searching for every single material in different websites/online stores and comparing prices the most boring step of that process? If so, would you like to have a tool that would do that price comparison for you? If not, what do you think is the most boring step? Thanks in advance :)

Topic by MarianaM56   |  last reply


Please can you Rate?

Please can anyone rate and suggest for my new instructable: https://www.instructables.com/id/Recycled-Milli-Volt-Power-Supply/

Topic by Patel Darshil 


Source Code Window in Instructable Page

Hi, it's my first time to write an instructable. I wanna add a few lines of source code to demonstrate in a page. I saw many people has done that.I searched in google but couldn't find it. I think perhaps it should be something like HTML format. Anyone could help? Thanks very much! Jichun

Topic by penguin007   |  last reply


arduino uno programe

I am new to arduino programing and have below query. i am getting below content in abc and wanted to parse and compare with current time. char abc[128] = Fajr5,04:40 Sunrise6,06:03 Dhuhr13,12:39 Asr17,17:16 Sunset19,19:15 Maghrib19,19:15 Isha21,20:37 ; how do we parse and get something     String time[] = 04:40 06:03 12:39 17:16 19:15 20:37 ; and then split and compare with current time. i am getting time from ds3231, hh=hour and mm=minute then compare like below     int h = time.Split(' ')[0].Split(':')[0]; // this is 04     int m = time.Split(' ')[0].Split(':')[1]; //this is 40     if(hh== h && mm==m)     {         Serial.print("Fajr");     }

Topic by sayedfar 


comments

Am I missing something? Does anybody know how to order comments oldest first. This most recent comment first thing is making me nauseous.

Topic by hazmat456   |  last reply


How to pick best battery for amplifier?

Hello, I ordered this amplifier and I need to pick best battery for this amplifier. Would be great to power it for at least 3-4 hours on maximum volume (200W rms subwoofer and 2x50W rms speakers). I need lightweight battery and powerful battery, size does not matter, budget is low so nothing overpriced I do not want.

Topic by RobertasP4   |  last reply


How to drive Bipolar stepper motor using MTD2006 dual H-bridge

Hi I'm trying to drive a Bi-polar stepper motor using MTD2006 bridge which I got from old copy machine.But when I download datasheet for this IC found that input signals must fed to drive the motor (ENA A,PHY A,ENA B,PHY B ) As I understand ENA signal must be (High) always! So I'm confused how to drive this IC using Arduino? Thanks

Topic by MHA6 


Feature Request: Download attachments (Premium)

I would like an option, as a Premium Member, to download all attachments for a project. I mainly look around in the Arduino area and I would like to download all files the authors have attached at once, instead of individually right clicking SaveAs and typing the name of the file.

Topic by Sensath   |  last reply


electronic switch

Hi, i'm a bit new to electronics. I was wondering if its possible to turn on the flow of current by another electrical signal. Yes, i know about transistors and relays but these switches turn off as soon as the second current is stopped, how to make this change in switch permanent, i'll be precise, i'm working on a laser alarm system, and it works fine, but the thing is that when i block the laser, sure the buzzer goes off, but when the obstruction is moved, the buzzer turns off, how can this be kept on until turned off manually by a switch. i know it must be quite simple but i dont know, please help thanks

Topic by walee    |  last reply


Finding authors who like to share and co-operate with their instructables

This is Kalimov. I am now working in an education company called Shanghai Genius Education Technology Co. Ltd. that mainly deals with schools in China. I am also a maker, too. For several years, I've read about instructables on instructables.com and many of them were quite amazing, both in techniques or ideas. I think why not introduce them to kids in schools of China? I've asked the staff commitee about my idea and now I'm sharing this idea to you. Below is my thinking. My company wants to introduce some overseas instructables to schools in Shanghai or other cities in China. We also want to publish books of tutorial compilation. We are willing to translate English to Chinese. We like to share the backstories of a making and autobiography of you. What we need is your permission that you like to share or write out how much benefit you want (PM).  Summary: In the book and the app we are going to publish, there are introduction of instructables.com, your profile and tutorials, your backstories. We share the benefit from education market. All sales reports are going to be visible to everyone. Besides, I also collect some of my crafting these years and I have made a post here. https://www.instructables.com/id/Some-Pictures-of-Crafting-I-Made-These-Years/. Thanks to Mike Asarus, Liquid Wash Hand and many members in instructables.com that they keep inspiring DIYers all the time!

Topic by Kalimov Lok   |  last reply


Guitar amp doesnt play sound in headphones when pluged in.

Hello, so I have a Orange amp, the crush 20 rt model and it plays just fine. When i want to play the sound to the headbphones it doesn't play. There is amp amp plug and the headphones plug, next to the headphones is the aux where i plug my headphones, but when i play, the sound doesn't go to the headphones. Any solutions? Also sorry if there are any mistakes in my engrish.

Topic by BacharH   |  last reply


Fidget Spinner Contest Bug "invalid for contest"

I submitted a couple of projects to the findget spinner contest.   https://www.instructables.com/contest/fidgetspinner/ One was recycled.  One was totally new. I get the following message for the new project:  "The entry is invalid for this contest".

Topic by mtairymd   |  last reply


Unable to favorite.

For some reason I am unable to favorite some, not all, instructables. It's almost as if there is an error in the script that prevents it from fully loading properly. See images. And yes, before anyone asks, I have tried disabling my adblock and reloading the page. Still does the same thing. Google Chrome 59.0.3071.115 (Official Build) (64-bit) (cohort: Stable) OS Windows JavaScript V8 5.9.211.38 Flash 26.0.0.131 User Agent Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/59.0.3071.115 Safari/537.36

Topic by Snoopy101x   |  last reply


How many pieces counts my knex ball machine Revolution?

That's my question for you! Here is a link to Revolution (with more pictures and a video) You can only enter one answer. This are the prizes: 1st place: 6 months pro membership and a patch 2nd place: 3 months pro membership and a patch 3rd place: a patch The contest closes Friday, 18 July 2014 Good luck! ~Sandroknexmaster~ ____________________________________________ Results! Total number of pieces: 13531 1) dr. richtofen (12369)                     6 months pro membership and a patch! 2) myOmy (12345)                            3 months pro membership and a patch! 3) Knexmaster888 (14948)               A patch! 4) Sorunome (15000) 5) Gargamel-Knex (15316) 6) didexo (17343) 7) nerfrocketeer (17344) 8) ~KnexBuild~ (18016) 9) Knex2thelimit (18292) 10) Zombiekiller-93 (7000) 11) akshat21045 (21045) 12) FlyingFish10 (118999881999119725) Thanks for entering! ~Sandroknexmaster~

Topic by sandroknexmaster   |  last reply


How can I install a new top spray arm for an old dishwasher?

How can I install a new top spray arm for an old dishwasher? It doesnt have a top rinsing thing. Would I just create a hole, adjust water pressure, and connect tube to where i would install a spray arm frame? Also, any way to overwrite the regulations to let my dishwasher dry without needing a rinsing agent? I know on some clothes washing machines, you can "cheat them" to use more water.  Thank you!

Topic by JuliaM115   |  last reply


Audio Transducer

Hi, how/where can I harvest (audio?) transdcuders, preferably bone conducting ones?  Like this; https://www.adafruit.com/product/1674 Which devices will have them? Old tv's, vcr's, pc's, amps....anything..?

Topic by isaacacheampong 


creating a light that works on a blood pressure sensor/heat sensor

Hey I'm new here and have recently been thinking that I want to create a light that would work (i.e. turn on) when specific readings from the body are met. So far I have when a low and stable blood pressure reading is met (indicating happiness) or when a specific temperature reading is met (also can indicate happiness) I think I'm more inclined to want to build it with the blood pressure reading as the heat one could just turn on if you are hot. However I have HONESTLY no expeirience in building electronics but am really keen to learn! Could anyone point me in the right direction to where I should be looking please and what some of the steps I am going to need to take are please?  In my mind it would work when a blood pressure reading is taken and the monitor shows a reading within the healthy and happy range. However I literally have no clue how to tell a lamp to turn on when this is achieved  please please help me out!  thank you so much in advance Holly :^)

Topic by holly_westall 


Water Release Mechanism - HELP!

I've been racking my brain trying to figure this one out, and thought I'd ask you guys. I'm building a project which requires the release of a tethered "buoy" once this sinkable object hits the water. I know I could use a mechanical release - a water sensing probe that trips a servo release - but I would rather keep it really simple, and use just chemistry and/or physics to do the work, and somewhat quickly, within a minute or two. I'm thinking that something must dissolve, expand or contract quickly when in water so that whatever is holding the buoy to the sinking object releases, and the buoy just floats to the surface. Making a toilet paper "fuse" has come to mind, but I was hoping for something more solid. I considered salt (as formed into a salt lick) but because it's so dense would take a long time to dissolve. Sugar cube seems too fragile? Any thoughts would be appreciated!

Topic by PatrickA117   |  last reply


Piezo Sensor to Detect Vibration Through Glass

Hello,  I am working on a project where I need to detect vibration through glass panes or on the surface of a window. I am currently planning to use a Piezo sensor with Arduino to detect and record different tests. I want to make sure that the senor is able to pick up the vibrations and not be too sensitive and pick up other things around it. I may need to tune the sensitivity. Besides the Piezo sensor I was also looking at the Parallax 605-00004 Piezo Film sensor (any advice on which one to use is appreciated.) If there are any other sensors that anyone may know that could work in this case, please let me know. I don't have a clear vision but any help to find out how I would go about this is greatly appreciated.  Thanks for the help

Topic by surajshah1   |  last reply


small 12v heater element control

Hi, looking for a bit of advice from electronically literate folks... I'm planning a low-temp water heating device that will keep a water/yeast/sugar solution at around 38C to produce optimum levels of CO2. so far what i have in mind is using a cheap 12v car immersion heater (the type used for making hot drinks on the go), powered by 4 x 3.7v lithium batteries in series (giving me roughly the right voltage range). The part i'm now trying to figure out is regulating the heating of the solution. I'm considering using an LM35 component to monitor the temperature via contact on the outside of the vessel. What i'm stuck on is what other components would i need in the circuit to take the  voltage output of the LM35 and use it to control the 12v immersion heater to maintain a temperature of around 35 degrees? Any advice would be much appreciated, thanks!

Topic by RionZion   |  last reply


Show Me Your Epic Fail Projects!

Any good maker will tell you to accept and embrace the process of iteration. And a natural product of that iterative process is failure. You learn a lot by trying something, being less-than-successful, and then attempting it again. It's the act of picking yourself up and trying again that helps dissolve the fear associated with failure. I'm interested to see your most epic failures! Share photos, videos, and stories of your fails from project builds: Slumping, cracking, burned, melted, misshapen… it's all part of the learning process. Can't wait to see how you messed up. :)

Topic by xxlauraxx   |  last reply


Need help to realize an idea: "Projector-Ruler"

Hello there, thanks for attention. I have an idea "Projector Ruler" ,which can show a ruler or other measuring tools on the wall, so that can help people to read the information of target easily. My concept have won international design awards, including Spark Design Award and IDEA. I think this idea is possible, potential ,and required by the market. You can see more detail in video or by following link: P-Ruler I plan to realize this concept. However, my study background can't enough support me to implement it. So, I need someone who understand the principle of projector, rangefinder or other related knowledge to help me to build this idea. I hope that we can group a team to generate it and co-found it. (The funds can come from Kickstarter :D). If you're interested, please contact me or make a comment. Thank you. P-Ruler from Chang Yu-Chung on Vimeo.

Topic by Yu-Chung 


LED Lamp Buzzing (not a bulb)

About a year ago, I came across this LED lamp that was on sale at my local Target store. It caught my eye because it had a little tray at the base of the lamp along with a USB port for charging my devices. Since the first time I plugged it in and turned it on, it makes a buzzing noise. At first it didn't bother me, but now that I am spending more time at my workbench it has become annoying. I understand it is kind of common for LED bulbs to do this because of the dimmer switch being outdated, however this lamp is not dimmable nor is it a "bulb" so to say. It's about 7-9 SMD LEDs on a circuit with a rocker switch. If it makes a difference, I do have my lamp plugged into a surge protector and don't have anything plugged into the USB port located at the base of the lamp. What can be done (other than throwing it away, of course) to stop the buzzing noise coming from the lamp? Thanks in advance!

Topic by TXVisual   |  last reply


Cool gel mats for pets

Hi, all! I foster dogs and cats in Baton Rouge for several non-profit agencies.  Lately, I've had more than a few feral cats needing a temporary home.  I had an idea (inspired by something I saw online) to use the trunk from the crepe myrtle tree my boyfriend chopped down to "catify" the carport where they like to seek shelter at night.  Considering that I've never owned a power tool until now, I think it's coming together nicely so far (pics attached).  Please keep in mind that I'm no carpenter....   This is south Louisiana where the Summer temps are high and the humidity is even higher.  I can only imagine how awful that must be when you are sporting a full fur coat outside!  Here's where I need your help:  I want to make cool gel mats to fit the odd shaped green shelves you see attached to the walls.  I have been sewing for many decades, so making these "cool" cushions to fit is not a problem.  The problem is how to make the GEL that goes inside the mats that keeps the pet cool.  I'd rather not use any toxic chemicals, just in case one of them punctures the gel mat causing it to leak and then decides to drink the gel.  So, maybe there's a chemist out there, or just some intelligent individuals that  might have the answer to my problem?  Any and all suggestions are very much appreciated! Thank you, Linda

Topic by Lbcaswell   |  last reply


type of soldering wire use

Hello, I have a 60/40 rosin core solder wire. Then I use a 220V soldering iron. Now whenever i tried to melt it, it took short while. compare to those wire in which you can melt it by only touching it with the iron. It's because i tried to repair a headphone jack and I still got where to solder it. Top - Green 2nd - Blue 3rd - Copper  4th - Red It was based on its current solded positions between the thin wires and the 3.5mm jack. now I'm asking what kind of wire do I use. I saw other video tutorials on how to repair a headphone and whenever they solder it, it was a spot on. Thank you.

Topic by MikoT7   |  last reply


LM35 circuit design

Hi, any advice on putting an LM35 into a circuit to control a small (120w max) DC immersion heater element so that it maintains water temperature around 38C ? Thanks

Topic by RionZion   |  last reply


Where is gone Pixlr editing in the EDITOR?

I remember that was possible directly edit the pictures in the library via PIXLR...is gone? It was only via Mobile App???

Topic by Skyfinder   |  last reply


Hi3516 Access Root Error

First, I apologize for my english. I have a camera module with hi3516 SoC and have to access to hi3516 as root. But I couldn't that. If I begin to explain from start. I had an IPC, extracted it and now I have 3 modules (camera module, ir cut module and power / api module). I found 3 holes on camera module, these are GND, Rx and Tx. I soldered them with 3 female jumper cables and connect to ftdi module. I used micro USB to USB for ftdi-pc connection. Powered up camera module with 12V. In while, I download a program, what name is coolterm, to my pc. I opened coolterm and set baud rate to 115200 (hi3516 standard). Camera module booted up. I pressed a button when I see "Hit any key to stop autoboot: 1" text. Until here I followed an article and everything is fine. But that article says "You have to press enter after to type "root" to gain shell access" and I can't access shell when type "root". I got an error like "Unknown command 'root' - try 'help'". Hi3516 has embedded linux os. Article Link: https://felipe.astroza.cl/hacking-hi3518-based-ip-camera/ Any ideas to help me?

Topic by Anıl Enis 


Hi3516 Telnet Access Error

First, I apologize for my english. I have a camera module with hi3516 SoC and have to access to hi3516 with telnet. But I couldn't that. If I begin to explain from start. I had an IPC, extracted it and now I have 3 modules (camera module, ir cut module and power/api module). First, I tried access to hi3516 as root. But I couldn't that. Then, I go on another method, telnet. I once cut the network cables of power/api module for some reason. Now I soldered them to each other and connect to internet with a rj45. Powered up camera module with 12V. I open advanced ip scanner(for detect ip address of camera module) and putty when camera module booted up. I typed ip address of camera in host name or ip address box and select telnet in connection type. Then, I clicked open button. A console window came to my screen when putty configration closed and I typed username and password correctly. But I got a warning when I typed right username and password. I can't remember how warning was. I got an error like "Login incorrect" and have to try again totally 3 times for every connection when I type wrong username and password. I followed an article for all of it. Hi3516 has embedded linux os. Article Link: http://www.hkvstar.com/technology-news/china-ip-camera-configuration-firmware.html Any ideas to help me?

Topic by Anıl Enis 


Need help finding a certain project

I am on the Instructables email list, and there was a project that was on an email earlier this year.  I really wanted to do it with my kids, and I got the items I needed: ON/OFF Switch With Cover 4x 1.5V AA Battery Holder Battery Case Battery Box with 5.5" Black Red Wire Leads and 5000 RPM 6V High Torque Cylinder Magnetic Electric Mini DC Motor But I have FORGOTTEN what the project was, and I no longer have the email!  I do know that I ordered the items above on May 21st, so the project had to be in an email on that day or a bit earlier. I’d really like to make whatever it was with my kids… can anyone help me?

Topic by deblevy   |  last reply