Alternative knex gun power source

I think this situation has happend to everyone once(pulls pin back)*SNAP!* "dang it, my rubber band broke"and let me say i HATE it when that happens, i got so tired of it that i decided to try an alternative, what did i use? Springs! I bought a pack of springs for $3 and lets say they work perfectly! they made my new sniper rifle fire over 80 feet before it hit the wall, so i dont know the exact range and i though i was set for a month of 2! ...well untill the 3rd day of useing them... the one i was useing got alot weaker i started to realise before i could hit the target on the wall without aiming upwards, now it dose not even reach 60 feet! (i noticed after i did my video) my first reaction was to check the breach load for any fragments of broken cartrages. none to be found. i thought "oh maybe the pin's tape has to be replaced (easy enough) as i took the main gun peice (the part of real barrel and breach load stuff not like handel or stock) it hit me! when i first used the gun my shoulder would pop and i could not get that strong in 3 days. and as i stared at the pin it seemed the spring had stretched! (this is a expantion spring so thats not good) now i am very upset cause i am on the 2nd spring and it took me forever! to get the pin exactly right the first time.so thats why this is here for any good ideas on how to have strong (yet long lasting) power sorces cause lets say RBs dont seem to like me and springs can get anoying and expencive.

Topic by Sypran   |  last reply


Undercabinet LED lights from 110v source

Hello, Ever since i moved into my current home I have wanted to put in under-cabinet lights in the kitchen. Its a small kitchen but the current fluorescent lights are just not giving me the light I'd like.  Powering the LEDs is my only concern. There are two under-cabinet areas each with one type of florescent light fixture with a normal 110v power line running into each light directly from a small hole in the wall (all hidden of course under the cabinets). There is no power outlet associated with these two lights. There is one outlet along the wall but I would not like to use this if possible as it powers the kitchen appliances, and it would show the power cord from the lights (Id love for these new LEDs to remain hidden.) I understand to use a 110v source I would need a LED transformer of some kind, I have seen these for sale, but I do not have an outlet that this transformer can plug into. Like this: http://www.ledstrips8.com/20-singlechip-smd3528-waterproof-aluminum-shell-rigid-led-light-p-118.html Is there a way to connect a type of transformer to this direct 110v line? Would I splice the plug off the end of the transformer and just crimp it to the 110v source from the wall?  Like the end of this transformer: http://www.ledstrips8.com/led-power-supply-110220v-ac-to-12v-dcindoor-use-p-70.html Im currently at work but if pictures help I can upload them later. Thanks!

Topic by billium28   |  last reply


LM386-amp power problem

I have built an LM386-amp from the schematic in Nicholas Collins "Handmade electronic music". It works fine with a 9v-battery but when I use a Roland guitar pedal power supply (several outputs) my chip is ruined. Does someone know how I can get this to work with a DC-adapter?

Topic by daaaaavid   |  last reply


Building a cooler radio. What should I use for a power source?

Building a cooler radio using a motorcycle 300w amp with ipod, marine speakers, and old coleman cooler. What should I use for a power source? Thinking about a 12V rechargeable battery. Are there better solutions to supply power?

Question by    |  last reply


"Organ donors"... or: sources for tube project parts...

The "Vacuum Tube" group needs a first forum topic. Here it is... Sorry 'bout the pun... but I could have used Time to get Organized... Be thankful ;-)Vacuum tubes and parts tend to be rather expensive these days. But there's a good source for parts, and it's often free: old tube organs.I picked up a working 1960 Wurlitzer a couple days ago. It's got:-- full complement of tubes (the mother lode!), including9 (nine!) 12AX7 preamp tubes.2 6L6-GC power tubes1 5U4-GB rectifier(there were other tubes: (28!) 12fq8's but they're not so useful for audio...)-- Huge power transformer-- Large (20-25 watt) output tranformer-- two 16 ohm speakers-- lots of carbon-comp resistors, sockets and other reusables.Total cost--just gas, and a sore back.Even the non-tube organs are a good source of speakers, reverb tanks, pedals, etc. The tank, bass pedals and the volume pedal were from a solid-state Conn organ left on the curb...The bass pedals could be made into a MIDI project, and the volume pedal would be a nice start of a wah, or left as-is. Yeah, they are grungy, but that's easy to fix....

Topic by gmoon   |  last reply


Are 12 gram co2 cartridges a viable power source for small rockets?

Would it be practically possible to use 12 gram CO2 cartridges like those used for bb guns to power small rockets? I have high hopes for this, but I don't know how well it would work. I am going to go do some ill-advised tests, but I would like to know if anyone has tried it and what I can expect.

Question by ilpug   |  last reply



How could I create an external power source for a set of computer speakers?

I am wondering if any one knows of a way to power computer speakers. I was thinking something along the lines of a car battery charger and a converter. Could anyone help me out with this? Thanks

Question by sardines454   |  last reply


Can you amplify and power a telephone keypad?

I have an old telephone keypad that I want to amplify, but I believe it needs a power source to do so? I've already used the telephone to make a microphone. I'm not looking for suggestions regarding making "songs" with the keypad, I can do that. I want to know how to amplify the keypad sounds.

Question by fooman1994   |  last reply


Power supply switch for boombox project...

Could someone help me with some simple wiring questions? I've built a little boombox using a Lepai amp and some speakers. At the moment the back is off the box that houses the amp, so I can plug in a mains power adapter, but I've got a housing for 10 x rechargeable NiMH AA batteries making a 12v battery pack with maybe 20 amphours of life in it. I've only just ordered the batteries so I'll see. However, I was thinking that I'd still like to have a socket that I can plug the mains adapter into. So I was thinking about mounting a DC socket on the back plate, and some sort of switch to select the power source. 1. Does the switch need to be a 3 position one? There's an on/off switch on the front of the amp, so maybe a 2-way switch would be OK? 2. Does the switch need to be some sort of special one because it's switching power. Would something like this one do? 3. The switch has 3 terminals. How do I connect it up? I'll have +ve and -ve from the battery pack, a +ve, -ve, and earth from the DC socket, and a +ve, -ve and earth going to the amp. ...or maybe there's an easier way of doing it? Thanks.

Topic by contadino   |  last reply


How would you heat water using no electric equipment or fire source?

For example if a hurricane knocks the power out and you need warm or hot water?

Question by thom23   |  last reply


Is it possible to make a Single Speaker Self-Powered MP3 player amplifier, with amp powered by player's right channel?

Can you make a one speaker mp3 amp that amplifies the left channel, and drives a single speaker, and uses the right channel as the amps power source? The right channel could be rectified and smoothed, but would it be enough power to run an amplifier that amplifies the left channel and drives a small speaker. Would it work? Would it be louder than simply running left and right speakers directly off the MP3 player?

Question by zylascope   |  last reply


How can I make a series of LEDs, powered by a wall plug, flash to an audio source?

The following Instructable is really helpful, but I don't understand the circuit diagram and the picture that shows how everything is connected isn't very good. I have to build a house project for physics and I wanted to incorporate this thing into it. We are allowed to use plans from this website, I just need some help. Could anyone explain the diagram to me or -even better- take a picture of what the actual setup looks like when everything is soldered together (I just need to know what connects to what)...Also, I need to power it off of a 9v wall transformer...THANKS!!!https://www.instructables.com/id/Blinking_LEDs_to_Music/?ALLSTEPS

Question by nick021892   |  last reply


Building a 5V or 12V powered in-line preamplifier

I want to build an in-line pre-amplifier with a 3.5mm in and out jack.  What I want, or at least think I want, is a simple booster that provides a small, but relatively even gain boost from an MP3 player into the main amplifier. Something along the lines of this: https://www.instructables.com/id/In-line-headphone-amplifier/ However, I would like to be able to power it off of 5V USB or off of the 12V coming into the cigar lighter. What I'm effectively trying to do is get enough gain on low volume spoken-word audio coming out of my mp3 player so that I don't have to crank the stereo up to max.  Does anyone have any good sources for instructions or advice for this sort of thing? Alternatively, someone can tell me if this is a fools errand to begin with, and that I aught to be taking a different approach altogether.

Topic by wildgunman   |  last reply


A Pi-powered Portable Experimenter's Bench, PEB

We are appealing for your support for our startup project, to turn our vision into a reality.  Our vision also includes anytime, anywhere, hands-on learning for STEM topics.  STEM = Science, Technology, Engineering (Arts) and Math. We are a small startup operation building a new resource for hobbyists, or electronic hobbyists-want-to-be--a smart experimenter's platform that removes the sometimes difficult bits and bytes, and relies on your PC, tablet, or smartphones for user-interface. For instance out of the box, our PEB, allows experimentation like Measuring speed of Sound, Locating source of a sound, Determining direction and distance of a Sound, etc.  with our PEB, configured with Ras-Das-1 and Audio Explorer board, totaling for less than $150, plus shipping. See--http://www.kickstarter.com/projects/254558907/data-acquisition-system-for-raspberry-pi and our website http://www.WattminderInstruments.com, for details. We need to have minimum funding to get PCBs and assemblers under contract to produce them, and on  a portal  like Instructables  to help us distribute them around the world.   Please let your  members know about our product and future plans and invite their support to make it a reality.  Electronics is the gateway to science learning. Thanks for your kind consideration and support. -Steve  and team

Topic by syang8   |  last reply


Why you can never have a "true" knex semi auto with decent power/range.

Ok here goes I will try to simplify my theory down a bit so everyone can understand: basicly energy cannot be created or destroyed, it can only be converted, eg kinetic into heat, chemical into kinetic ect. Knex guns are no exception, the enery has to come from somewhere, in most guns this takes the form of pulling back a pin or rubberbands to create potential energy, this is released when the trigger is pulled, this potential energy is converted into kinetc energy and this is how the bullet is fired. A semi automatic gun is required to fire every time the trigger is pulled, but the energy still has to come from somewhere. RBG's take this into account as each band is pulled back and has potential energy stored, however many knexer's opinions differ on whether this is truly semi automatic, many calling this type of gun a psuedo semi auto. Other guns use the energy imparted on pulling the trigger to create the potential energy to power the bullet, this is considered to be a true semi auto, however the main drawback of this system is that the amount of energy that can be transfered from the trigger to the bullet is very limited, therefore this type of mechinism has limited power. So if the problem is energy how do we solve this? one possible answer is to have an extra source of energy, such as a motor or a winding system that puts extra energy back into the system, however this approach will not give you a "true" semi auto as you will have to have an external source of energy, that and the fact that knex motors do not have the power and torque needed for this system. So what's your opinion, do you have anything to add?

Topic by Fred the Penguin   |  last reply


case mod on a 360. need help with led lighting?

I used the 12 v power next to power inlet. ok i wired total of 8 leds in parallel. 6 of them are 1.9 volts and the other two are white leds of 3.3volts. now my white ones dont have power they dnt turn on . i wanted to make an effect of a really bright inside but i think i dont have enough power. i want to stick to this one 12 volt power source. whats the best way to go about putting the leds.

Question by omarg8900 


How to wire a ciruit to charge a lead acid battery when needed and power a audio amplifier? Answered

I have a small audio amplifier i am trying to power off of a lead acid battery to make it portable.  I want to make it so when you plug in a power adapter it will be able to charge the battery and run the amplifier at the same time. It is a 30 watt amplifier.  Should i connect the power adapter to the charging circuit and the audio amplifier in parralel? And then connect the battery to the circuit in parralel? I was thinking of using a laptop power adapter as the power source. I forgot to put a diode between the battery and the amp to prevent the power supply from charging the battery directly through the audio amp parralel connection.  Would this work? Else what should I do?

Question by snowluck2345   |  last reply


I have a 6v mini solenoid mounted on a wheelchair that needs to open twice daily for 20 seconds. Answered

I want to connect a Power source to a solenoid and a toggle switch. See photos below.

Question by RaymondB56   |  last reply


Somebody would teach us how to recharge a dead car battery with an old pc source power....? Answered

I`ve heard before that someone reload his dead car battery plugging it to an old pc font...but Ì would to know if somebody already do this...and if it works...

Question by Mr.Sanchez   |  last reply


re-using a set of bose speakers for a laptop?

I have a set of Bose speakers I'd like to be able to hook up to my lap top,along with a volume control, but I'm a noob when it comes to electronics. I also have a few 4.5 volt power transformers from old answering machines I could use for the power source. Any help is appreciated.

Question by zombiejeezus   |  last reply


Need pin connections and source of connectors for Sony 8GB Walkman MP3 player and Ipod

My girlfriend's Sony Walkman 8GB MP3 player is a Model NWZ-E430. It is difficult to find docking stations and accessories for Sony units in retail stores, and few options exist even online. I'd like to build a docking station with high-quality amp / speakers for her. I am an electronics and computer tech by trade, but this is my girlfriend's player. I don't own one, and have not experimented with them. I need to know the pinouts (connections out of the Walkman) to connect it to the docking station... polarity of power connections, speaker outputs, etc. I also need a source for the Sony connector to fit into the Walkman. Finally, I need to know what the pinouts are for an Ipod docking station, in case I find one that I want to buy and hack, so it will work for the Walkman. Not having an Ipod, I do not know if they are the same type of connector as the Sony, but I assume they are different.

Question by Countrywings 


How do you reduce 6 volts to 4.5 volts? Answered

I am working on a toy truck that will play music, have headlights that will light and a gear system that will lift the truck up and down when a switch is pressed. The music (took from a stuffed keychain pig) and lighted headlights (Blue LED) work using 4.5 volts. My gear system use to use 4.5 volts to lift the truck, but now it won't do it. In order to lift the truck I have to increase the voltage power to 6 volts. If I increase the power of the gear system to 6 volts or more then it will fry my music and lights (however, I can make adjustments to the LEDs with resistors). The higher the volts are for the gear system, the easier it is to lift the truck. Maximum volts for the system are 12 volts. I know lifting the truck puts a strain on the system but the more power I give it; the better it can lift the truck. My goal is to use one power source and one switch. I thought I could use to different power sources (6 v and 4.5 v) and connect it to one switch, but I think it will fry of my music and lights. My question is: How do I reduce 6 volts to 4.5 volts, using 6 volts as my main source and connect everything to one switch? If I can get this figured out then this will help me with future project, where I need to use voltage reduction (or is it called voltage regulator). My knowledge of electronics is very low or enough to get me in trouble, which it has done. I am familiar with a few basic electronic terms and formulas. I will except and appreciate any help, ideas, diagrams, etc. Please use layman terms.

Question by mates   |  last reply


Need 2make a low cost but bright wash light 4samll scale drama 4our prayer group. God bless u 4 all d help. Prefer LED

Want to make a RGB LED 64par can of 1w or 3w LED m a novice so i need to know how to connect the LED's and how to make or control the color change ? i want to use a 240V Ac power source too Will this par can be as bright as the original one. How many LED would be required  What details should one keep in mind before purchasing LED and other stuff If LED is not  bright enough can we use a car headlight HID  lamp how do connect to Ac power source Use is for stage light / Wash light 

Question by malcolm2979   |  last reply


If i make 5 LM1875 circuits, and put them in series, will i have 100 watts output power? Answered

What i mean is can i set it up like: audio source> input amp 1> output amp 1> input amp 2> output amp 2, etc... will there be around 100 watts ant the output of amp 5? Also can i use the same power supply for all 5 and put the voltage inputs in parallel? (i.e. the 5 Vcc's in parallel with the positive output from the power supply, 5 Vee's in parallel with the neg of the power supply) heres the national semi page for it: http://www.national.com/mpf/LM/LM1875.htmlif for some reason this doesnt work, can someone link me to a ~100w solid state amp, preferably something simple like the lm1875

Question by tigerdog330   |  last reply


Is it possible to convert a headphone amp into a speaker amp?

I bought a cheap replica of Apple's Universal Ipod Dock, which has a line out (includes an LM4811 amp chip). My goal is to convert the headphone amp to a decent speaker amp -- similar to the Altoids Tin Speaker (https://www.instructables.com/id/Altoids-Tin-Speaker/), but without the battery or switch. I want all of the power to go through the dock's PCB, so I'm trying to avoid as much as I can an extra power source just to power the amp.This is part of a larger project that I've been working on for a while (and learning as I go)I can provide pictures later on of the dock's PCB if anyone wants to take a look.

Question by jesuislebomb 


speakers

Hey you guys are all so creative and knowledgable, this site is so great (tho terrible for my procrastination) does anyone know how to build a speaker to fit certain dimensions? like how flat could i make a speaker, and how loud would it be for something only a half inch thick (if thats possible) and up to 12" wide? it is meant to plug into an mp3 for power source etc.

Topic by jojo101   |  last reply


Remote control 12 volt drivable BBQ? Answered

As a BBQ competitor, I want to build a remote control drivable smoker for amusment at competitions. My problem is how to find and size the 12 volt motor for the drive wheels (3" to 4" diameter).  Smoker weighs about 15 pounds (stand up Brinkman type) plus I have 12v 7ah surplus batteries from  my work that I want to use for power source. Dave Q

Question by Dave Q   |  last reply


Led Music Sync Lamp V 3.0. Help with circuit?

The circuit diagram is shown below and the source of where I found it. http://www.youtube.com/watch?v=Yd3hzYAJzOoOnly problem is, I have no idea what values I should use, what vdd, vcc, q1, q2, q3, u1, u2, u3 and where power comes in.Could somebody tell me vdd and what vcc is?And perhaps what this guy is using as u1-3 and q1-3?Plus where the power comes in.And possibly what resistor values i should use that correspond with: (5-12 volts your choice) and 3 regular 5mm leds @ 3.3 volts 20ma?To go above and beyond... you could make an instructable elaborating this guy's design. :D

Question by Dmxspider   |  last reply


mobile battery in cheap mp3 player

Help me i hv a cheap mp3 player which is not charging now...and i cant find its battery replacement in market... so i am thinking of attaching a mobile's battery(nokia bl-5b which i hv 3 in spare) to the mp3 player as power source ... my question is will it work since both battery gives output of 3.7v ??? and will it give longer playing time my... mp3 player was previously giving me roughly 1 hour of play time with that tiny 3.7v battery... ???

Topic by D3zire   |  last reply


water-based kinetic LED lamp

I want to mak a kinetic light using high-powered LEDs to produce glitter line through a thin layer of agitated turbulent water in a wall mounted shelf. So, this gives me a few questions, but let me start with the idea I've got. I want to seperate a shelving unit (preferably solid wood not particleboard with some decent HxDxW) into two compartments. A glass sheet would be slid into grooves onto the side supports. The upper portion of the shelving unit would then be wood, waterproofed with some thin styrene plastic sheets. The bottom would then be composed of a large aluminum sheet (recessed slightly upwards for astheatics) which would house several LEDs in addition to the power adapter and voltage regulator. This would likely follow the "powering high powered LED" tutorial's alternate power source to the pucks. At this point a small pump would be placed into the upper compartment along with just enough water to submerge the pump to a safe level. Perhaps a small recess would be included in the top to allow instant colour shifts by using stained clear plastic sheets (this would reduce total illumination, but these are to be mood/ambient accents not primary lighting source) to avoid any of the more expensive/complex colour shifting lamps. The big question I have at this point is how thermally safe this would be, and how much LED I would actually need to achieve decent brightness. Also, I would prefer if the bottom was modular enough I could remove and work on it without dissasembling the entire assembly, but this may not be possible. Finally, I was wondering if I could run the heatsink material up the ront of the shelf, past the glass, and into the water (this should give great heat dissipation) and have a SAFE and STABLE waterproof join between a flush glass-metal joint with possible use of epoxy and/or silicone caulking. Anything not specified in here I'm uncertain of how to do exactly. So! If anyone has any ideas, suggestions, or awareness that this is pure madness (or has a better way t oget those glitter lines i lust for) please let me know.

Topic by JRGumby   |  last reply


hey guys We need more instructables!

Hey ya'll I know I have'nt logged in for a while And I think we should all work on one big project you know "Colaborate" I think that we should make an instructable on how to make a autononomous turret using knexsuperbf. 's gun design and maybe dean 101 could program the turret or at least dig ups some code for it. But this can't just be any another knex/lego gun it needs to be fast powerful and maybe we could an ir sensor so it could track a heat source.

Topic by Pumpkin$   |  last reply


Mirror Heater/Demister?

Hi, I need some advice on how to wire up a homemade mirror heater or demister. I have an old toaster which I have gutted to get the heating elements. I also have a few old wallwarts to power the thing. Is using these wires the right thing to use as a heat source? It doesn't have to get hot, just slightly warm. What kind of circuitry will I need to warm up the wire? I also got some modelling latex to embed this wires in to make a heating "pad" for the mirror and to insulate it. Is there a better material I can enclose the elements in. Thanks.

Topic by Armbie   |  last reply


Remote Control K'Nex Car

Hello, K'Nexing community! It's been roughly three years since I last posted anything on Instructables. Anywho, I've finally gotten the motivation to create something out of K'nex, and also combine it with my favorite hobby of hobby-grade remote control cars.  This car that's featured would be a brushed, but also fast on-road cruiser. Features/Notations of vehicle: Powered by: 12T or 15T Brushed motor ESC: Old ESC from ECX Torment, or Traxxas Slash ESC RX/TX: Team Associated combo Servo: Team Associated servo Solid Rear Axle Power Source: 2S LiPo More details and pictures will be added over time, and hopefully it won't take another three years. XD I've also included a couple of pictures of my current RC cars.

Topic by beanieostrich   |  last reply


Headphone Amp For Laptop DJ

I use my laptop to play music...(using virtual dj software)....splitting the jack .. the volume from headphone is ok when playing small system.... big system the headphone volume is low....i need more ..i buy a volume switch (B5k) thinking that will solve the problem  ..but when i connect it and turn it up its the same volume i get as if i just connect it without... QUESTION can i add any thing to this to make the headphone louder..without using any external power source 6v,12v battery etc

Topic by hitek   |  last reply


LED Keyboard

Ok guys and girls, I have a pretty neat idea I want to try. I was playing my favorite PC game at like 3 am and I wanted to play in the dark but I couldn't because my keyboard is black and I couldn't see it, so a great idea hit me... I want to pull apart my keyboard and but some LEDs in it so when I plug it in LEDs light up the board behind the keys. my only real problem though is knowing where to attach the wires from the LEDs to the board so I don't need and external power source... So if anyone is out there and have the same idea or maybe even have done this please let me know!!!

Topic by animal0307   |  last reply


knex trebuchet

I have made a knex trebuchet which is about 3 feet in length and 2 ft in height. The frame is strong. It can fire quite far but I'll get measurements tomorrow It can fire anything that fill fit unfortunately it doesn't use weights as a power source due to having nothing that could be heavy enough to fire it so, I put loads of rubber bands on it. its fire using string which is attached to the projectile and the other end of the string is connected to the arm which when is up right the string detaches and the projectile is released. At the moment is can fire about 20ft and gets loads of air time. about posting this: I will test it tomorrow and iron out any problems and make it perform better. after all of that I will post it. my thoughts: I think this is the best trebuchet to be posted :)

Topic by smidge147   |  last reply


Can I build headphones out of drivers???

Ok... my plan is to use jackhammer noise blockers (im pretty sure we've all seen the mod) and 'install' 1 inch tang band drivers.my concerns: 1. will it be too loud I am the kind of person who prefers to not have throbbing ears when I am done listening 2. how can I power the drivers. these are headphones, so I need a portable source of power. I am new to speakers, and I dont know what type of power the drivers use. So, what I am asking is what type of battery do I need to use. 3. how do I set up stereo sound w/ 2 speakers in a headphone jack. there are instructions for how to connect a single speaker to a jack, but I am going to be using 2 4. any ideas on how to make it look cooler, paint ideas (spray paint only, no airbrush), where/how to put a battery container in the system, and how to make that look good.stuff: Drivers:http://www.amazon.com/exec/obidos/tg/detail/-/B000KGSYPW/ref=ord_cart_shr?_encoding=UTF8&m;=A385A0XNQBW8HY&v;=glance headset: either 1.http://www.amazon.com/exec/obidos/tg/detail/-/B000VU8U2E/ref=ord_cart_shr?_encoding=UTF8&m;=A17MC6HOH9AVE6&v;=glance -or- 2.http://www.amazon.com/Peltor-H10A-Professional-Canceling-Earmuff/dp/B00009LI4K/ref=cm_lmf_tit_13_rdssss0 any constructive comments welcome, but, please dont just say its impossible, unless you are absolutely postive it isnt

Question by airsofter2   |  last reply


Home heat exchanger or heat engine anyone?

I know for a fact that in the EU we can now have energy effient homes that utilise the heat from common sources like water heater, solar or just what is under the roof to generate electricity or heat other things.Started to wonder if ever someone tried something in that region on an affordable hobby level.Down here properly insulated homes are rare as a pearl in a supermarket oyster.So my main interest would in utilising the excess heat under the roof during the summer times.This season I measured and average of around 60°C during the day.On those day over the 35°C mark it went up close to 75°C in some areas.I guesstimate that if the draft areas are sealed off a bit a fan system should able to suck air at about 50°C out for about 6 to10 hours per day during the summer.If I would add a small heat exchange made from a solor hot water panel and some piping:Would hat combine heat output be enough to power an ammonia fridge or even freezer?What options are there that you guys created to generate some electricity from other heat sources?Thinking about the exhaust heat from the hot water system or heater.One thing I am planning on is a small solar heater for my big fish tank.Currently not anywhere near a window but would like some Arduino to control a water pump by temperature comparison to provide warm water during the winter months for free.Beats two 400W heaters if you ask me LOLThe potential for some easy to create heat exchange system to generate a bit of electrictiy or power heat exchange system is huge.Australia is full of badly insulated homes and the US is not far behind.And not matter how good they are all those homes still heat the roof cavities like hell.

Question by Downunder35m 


Contest! (winner announced)

I am holding a contest to see who has the best airsoft gun (in my opinion). all you have to do to enter is post a picture of you airsoft gun and state its: (1) price (2) fps (3) brand (4) magazine capacity (5) power source (electric, gas, spring) (6) weight (if possible) if you wish to post more than one gun, write another comment with each of the statistics listed in it, along with the picture. the winner will receive a patch and a 5* rating on all of their instructables. i will announce the winner saturday, 28/07/2012. get posting! entries: (1) dr. richtofen: m93 raffica, pump action shotgun, mp40, m14 socom, 90 two (2) Runeblader97: famas, lever action rifle (3) mberg: p226 (4) TheDunkis: magpul pdr winner:  the winner is.......... Runeblader97! i choose your gun because its low enough price, pretty good fps, high capacity and it was different to all the other entries, being a lever action. it was also nice to see a different airsoft gun that wasnt really modern. you will recieve your patch and a 5* rating on all your instructables!

Topic by ~KGB~   |  last reply


I Have My K'nex Back!

Well, I've got some explaining to do.  It turns out my K'nex was never actually sold.  My parents hid my K'nex from me, telling me they sold it, only to give it back to me extremely recently under one stipulation: I can't build guns anymore, unfortunately.  Trust me, I'm not complaining; I'm just ecstatic that I can build with them again.  I'm sorry for the huge lack of activity lately, but I haven't had that many ideas before I got my K'nex back.  My first K'nex creation in a while is this really cool compact lock.  Being K'nex, of course, I wouldn't advise that you lock anything with it, but it is nigh on impossible to open with force unless the button is pushed, or you deconstruct the lock itself.  It is powered completely by tension, and doesn't need any rubber bands or power source other than the K'nex from which it is made.  It is also extremely fun to mess around with, and I could spend about an hour just fiddling with the mechanism; such is my attention span.  I'm thinking about working on instructions, but I wanted to see what you guys thought of it first. The second thing I'd like to share with you all is this 3D Owl I printed over at Fab Lab in Chicago at the Museum of Science and Industry.  I would like to sincerely thank Matt Chalker, the head executive of the Museum of Science and Industry's Fab Lab, the museum itself, and all that make Fab Labs possible for such a wonderful experience.  Along with this owl, we made many things out of wood via the wood laser engraver, and finger puppets for each member of my family, depicting our faces, of course. (I have more pictures of both the owl and the lock.  If anyone is interested, I could post them in the comments.  They're pretty much the items on different backgrounds, though.) Enjoy! -DarkOwl

Topic by DarkOwlProductions   |  last reply


UV filtration in your fish tank or small fish pond

Year after year the topic "I have a fish tank" seems to go more out of control. What was once a hobby just to have some fish can now be a design feature both in your home and inside the tank. Realistic looking lasdscapes, optical illusions that make you think the tank is much bigger and the list goes on. But one thing that now always pops up is the must have thing of UV filtration. Or to be precise: UV-C sterilisation! Now, if we trust Wiki and our big water suppliers then UV-C will literally kill anything alive that comes into contact with. So of course it would be a good thing to have for your tank - or not? UV-C is very dangerous for your eyesight and quite harmful for your skin! Looking into a proper UV-C lamp without protection means you can go blind! Even good sunglasses might not have enough protection in the UV-C range, so only use them for additional protection but never without and glass between you and the lamp! Don't be a fool! Treat UV-C seriously! You would not look into the full sun with your sunglasses and would not expose your eyes or skin to a powerful laser, UV-C is to be treated the same way! Let's start by using some boring text to explain the concept a little bit. On a large scale special and quite powerful systems are used to treat our drinking or pool water. Here special UV-C lights with a wavelenghts of 260nm or below are used to shine through the water passing by. There are two key factors here. a) the wavelenght b) the water flow rate and the corresponding time the water is in contact with the UV light To ensure all bacteria, viruses, algae and other harmful organics are dead the water must circulate for long enough so even the last water molecule had a few seconds of exposure. All this only works good with "crystal clear" water for obvious reasons as otherwise the UV has to be even more powerful to pass through. Single cell organisms literally crack into pieces similar to being exposed to gamma rays, more complex cells like algae have their cell membranes damages and the DNA suffers as well causing reproduction loss and early death. Even some chemicals break down, most importantly here chlorine based substances. Differences within the UV-C range! If you bothered to check Wiki about the topic of UV-C you will already know that only certain wavelengths within this spectrum will actuall be powerful enough to do what we want it to do. And here is the first problem for us hobby users. Most cheaply advertised "sterlisation lamps" you find in places like Ebay are actually totally useless. Stating to be selling a UV-C light to sterilze your water in such a case is still not considered to be fraud though. Simply because it still does what it supposed to do, just very slow and with very little effect. Only the so called "short wave" UV-C range is powerful enough! To avoid loosing business during the times of the biggest hype in 20 years no seller will actuall state the available wavelengths. That means without this info anywhere you can be certain the advertised lamp is of little to no use. Even those advertised to be short wave UV-C might not be the real deal. However, if a decent manufacturer is behind the actual lamp used it is possible to check the datasheet for these performance figures - but again most cheap systems come with no-name lamps inside. Check the prices for a reputable UV-C light with the same lamp fitting, e.g. G23 and you will see it might cost more than your entire system. Ok, you have a poper short wave UV-C lamp or consider getting a canister filter with one in it.... Never, ever test your lamp without proper protection!!!!! UV-C will damage your eye within seconds! If you system or lamp does not provide a viewing port or shine through area then you have to place a piece of glass between you and the light! UV-C won't be able to penetrate normal window glass but will pass through quartz glass. Place the lamp in a box and cover with the glass. How make proper use of UV-C sterilisation... The replacement lights are quite expensive, so let's see how to get the most out of them. As said before exposure is the key factor so the flow rate of the UV system must match tank size and flow rate of your filter system. Canister filters with a build in lamp should be designed to match but I will tell you later what to look for ;) Most of us will prefer to have a in-line system if there is already a good canister filter at work, so I will focus on those and rop in solutions. If you compare in-line system you might notice that some quite small and low power units claim to allow for the same flow rates as for example 40W units. Some are fraud and just want to sell while others use simple physics to make the claim true. A good system will utilise an auger like "ramp" that forces the water to circulate around the tube many times - causing up to ten times longer exposure rates. Others create this sprial effect more like a vortex with some diverters and modified inlets. The later seems to be less efficient though with low power lamps. An in-line system should be on the outlet side of your canister filter so the best quality water will pass through it. A drop in solution should be used alone and without the existing normal filter pump you might have in there. Ok, got it, but how do I actually use it now? Despite common thinking a UV-C system should not run 24/7 like your normal filter. You really only need it to solve problems you should not have in a healthy tank! It is not a magical solution to make your underlaying problems go away ;) Let's start with the most common reason someone buys a UV-C system: An algae or bacterial outbreak causing greenish or milky water. If that developed slowly over a period of weeks then you would be better off to do a good clean of the tank and filter plus a decent water exchange. A few drops of meds will do the rest. And if you constantly get algae growing on your glass, ornaments and plants then your nutrient levels and water quality is not right anyway and needs a good check. But of course there is also the problem of light - too much for too long and unwanted gree appears everywhere. If in doubt reduce the light power, shade out natural light or reduce the on time for your lights. Having said that we now face the problem of a sudden outbreak after introducing new fish or plants. If you don't have a quarantaine tank chances are that sooner or later you get unwanted or even harmful guest into your tank. Here the UV-C will be beneficial, which is why a canister filter with build in light should have a seperate switch or power supply for the light. After an outbreak or while introducing new life into your tank the UV-C will remove a lot of the things that we don't want to bring along. For new life I leave the light on non stop for a week, that is for a small 4ft tank with 200 liters. To control an outbreak it depends on how bad it is. I assume here you can still see the back of your tank  but that the water either appears greenish or slightly milky from bacteria. As a personal thing I prefer to to remove and clean my filter material before treating a severe outbreak. Once done I fill the filter with a mix of activate carbon material and fine filter wool. Reason for this quite simple: The outbreak causing stuff is already in your filter material and will be a constant source of re-infection. And since breaking down all this bad stuff causes even more bad stuff to be produced as biological waste we want to discard it properly once done. Using just fine filter wool and activated carbon also reduces the flow rate bit if compacted ;) Now we can turn on the light and pump and forget about it for a while. It is not recommended to run UV lights on a timer as you want them on all time to prevent short lifespan and have ongoing treatment of the water. Good idea to take a picture at the same of a day from now on to compare and check results. After 3 days the water should definately be clearer, if not then either your filter material is packed too losse or the lamp is no good. Once the water appears to be clear do a readin test - take a newspaper behind the tank and check if the text is clear - blurry means the water is still not clean. You will reach a point where the water quality will not further improve as much as in the days before. This is the time where you discard or clean out to dry your filter material and put the original stuff back in. The activated carbon should be discarded of course. You cleaned filter material will now need a certain time to grow enough good bacteria to go back to the old performance. During this time you should still leave the light on. In most cases with enough fish and plants in the tank a week should be sufficient. After that you can leave the light off and keep the tank fit and healthy. Special case: Algae everywhere! Especially after getting a new plant you can end up with quite pesty algae growth. Be it these long ghost hair types or in a bad case the black stuff growing on plants, ornaments and the glass. I have even seen tanks with algae covering the entire bottom of the tank causing the gravel to look like carpet. Here I can only advise to set up a quarantaine tank for your fish. Then remove all infested material for manual removal and cleaning. Infested plants should be cut clean and what can be boiled should be boiled in water for a few minutes. Now start scrubbing in the tank with ongoing water replacements. I prefer to let everything settle over night without any bubbler or pump running. This way I can suck up a lot of sediment the next day. If you can remove all plants and fish you can now use hydrogen peroxide and add it to your tank water. But this is only feasable for small desktop tanks. Before using the UV as above to cure an outbreak you should consider all water one last time. Allow at least 2 weeks with ongoing water checks before adding plants back in and another week before placing your fish back in the tank. The week before adding fish should be used to monitor the plats for any signs of algae you might have missed - if you find any remove it! A week after the fish is back in you can turn off the UV light. Underwater UV-C light!? In most online stores you will find quite cheap UV lights to be advertised as underwater or in tank use. Although it might sound tempting you should be well aware of the dangers of using them. The glass of your tank will block the harmfull UV rays but the water surface won't, so either don't ever look at it or use proper sunglasses with real UV protection. Apart from the dangers to you these lamps are not just cheap in price but also cheaply produced. That means there is no way of telling how much or how little UV-C is produced. If they are good then you still need to know in what type of tank setup you can use them. As plants can tolerate a bit of UV a placement as far away from the nearest plant should do, especially if you can place a bubble wall betwenn light and plants. The fish is another thing as some seem to be unaware of the danger in their tank. This means they can get too close to the light but I have not found any articles explaining how harmful UV-C is to fish or their eyesight. I guess once your fish starts to bounce into everything you know... ;) My advise is to stay away from the idea of hanging a UV-C lamp in your tank, the risk for you and your tank is just not justified. If you need to go cheap then get two or thre of these lamps so you have spares. But use them externally ;) Meaning: Take a UV proof plastic container of small size and place the light in there. To be really safe tape the lid and all holes for the hoses with black tape. Place the container above the water level of your tank and if you only have an internal filter pump push a suitable sized hose into the outlet to feed into you canister. Check how high you pump can make it and place the outlet or overflow slightly below this level. When to change the light? If you made it all the way down here then you might already had the benefit of using light to "cure" your tank. Now we are faced with the high replacement cost for the lamp itself. Ususally only flouroscent tubes are used. It is always good to check after purchase what type of lamp and manufacturer (if there is one) was used. In some cases the system itself is like an inkjet printer: Just a cheap way to make you buy the consumables. Let's say you new in-line filter was priced at $100 to have a nice round number, some are cheaper some much more expensive. The lamp used might be an exotic type and not even be available easy, so before you buy your system check where you can get spares, not just the lamp of course. A replacement lamp can be as ceap as 20 bucks or cost even more than your system if you need to order it elsewhere. The quartz glass sleeve can break too meaning you then need a lamp and cylinder. Going with a reputable brand and paying a bit more certainly helps to get spares in the future. Let's just assume you either got your system in bulk due to the price of replacement lamps or can get them at a reasonable price. UV-C lamps are not like your normal flouroscent light tubes you have around or maybe even on top of your tank. Consider them like the tubes used in the now unhealthy tanning beds. After a certain amount of time they no longer produce enough of the short wave UV light that we need. As you can't see it and most of us won't have the means to specifically measure it we have to trust manufacturers recommendations. For most good brands the numbers are the same: 8000 hours max. Considering the costs it does make sense to keep written track of the usage. Not too hard since we won't use them like normal lights but instead have them on for a week or more without turning them off. I recommend to have a replacement at hand long before you need it. A lamp can fail premature, crack or simply burn out. The 8000 hours are based on 24 hour usage, so one day on, one day off. This could mean for us the lifetime can be slightly longer but I would not go over 9000 hours. As a rule of thumb: If the water does not show good signs of getting clear on day thre the lamp is due.

Topic by Downunder35m   |  last reply