I need a heat sink like this one, please help?

I have been looking to find a long heat sink like this one: http://www.anglia-live.com/products/kw/LAM-4-150-05-V/774353001_HEATSINK-FAN-150MM-5VDC but I can't find one that is cheaper or similar (Other than other models of this). I basically want to make a thin air conditioner with about 18 peltier units. I want one of those heat sinks on the hot side. I then want to do the same thing on the cold side or I want to use a bunch of mini 40x40mm fans on each cold side of the peltier units. Please let me know if you know any similar heat sink designs or if there is a name for this kind of design. Also, if there are no similar heat sinks, could I just go to Home Depot and buy a hollow aluminum square pipe and add a mini PC fan instead of this? I would assume it wouldn't be as effective because of the less surface area, but, it would be cheaper I think.

Question by knexpert1700   |  last reply


Power a 12VDC cooling fan using LEAST amount of space possible using a switch. This needs to fit in a small helmet. Answered

I bought a 40MM 12VDC Cooling Fan (130mA 1.56W) from Raido Shack and I am trying to put it inside my modded Mark VI helmet from the Halo video game series. I bought a small Switch from Hobby Lobby (teamnovak.com Switch Harness #5600) and a 9V battery. I know the volts are off so I need to know what I need to do/buy to get this working. I connected the fan (+) to the switch (+) and those to the battery (+), then the fan (-) to the switch (-) and those to the battery (-) It worked just how I wanted but after about 60 seconds the battery got VERY VERY hot. I did my research and found that this outcome is normal but couldnt find out how to fix it. PS: I am new to this website ans suck at electrical stuff. Any questions or pictures need email me @ hunter_ii7@yahoo.com (hunter_ii7)

Question by HUNTER II7   |  last reply


I need to make a fake or dummy 40mm (S10) gas mask filter?

So am trying to do cosplay and the character wears a s10 gas mask, the filter i received with it i was told not to use it after researching it because it can either be faulty or filled with apostates , none the less I need to make a copy of one, now I can either spend 35 dollars for some one to 3d print one (i impart feel that it wouldn't look best with how you can see all the lines from the print) or I was wounding if maybe i could make my own, now the one that came with it was some type of metal, so I thought maybe I could get sheet of metal and either cut it in a certain way or even bend it  to make it into the right shape, or I could make one out of wood and just get 3 planks and cut them into the right shape and glue em together or screw and paint it black, or lastly the newer models seem kinda plastic like or rubber like, so maybe get like a square of rubber from like a tire and cut it out, but the main problem is how do i make a 40mm size male screw so the filter can attach to the mask, and yes the filter does need to be hollow so air can pass through but i don't need a filter inside it 

Question by Mac yet more irish   |  last reply


speaker drivers

I'm looking for speaker drivers within 40mm-50mm and a full range frequency response of about 0-25khz But! i cant find any manufacturers within the uk at a cheap price or decent frequency range btw its for a headphone project im working on :D All help greatly appreciated (:

Topic by 00mike000   |  last reply


Where to buy large glass tubes?

I need several glass tubes (10-20) that are around 30-40mm in diameter and 6 feet long. They also can't be rediculously expensive, I've been searching for a while, but all I've been able to find is glass with a length of 4 feet and a diameter of like 10mm. Any help?

Topic by guyfrom7up   |  last reply


what will be the wire size ?if i would like to make a eletro magnet ?which length could be 1200 mm and core width 40mm?

Dear friends, I want to make a drum with magnetic bars, to capture max matal particals from amixture, size of magnet should be 1200mm*---- ,suggest me what would be the Diameter of wire Regards Nadeem

Question by nadeem Ashraf   |  last reply


i want to make a razer robot.....

I find some things like 12v solenoid valve , 12v hydraulic hump & motor ,but still can someone tell me ,how much SPI is required for mine hydraulic pump and what should be rpm for motor , mine robot's double acting cylinder's bore is 40mm and stroke is 150mm(15cm).. pls replay soon...........

Question by vish3385   |  last reply


Is there some sort of rigid tubing with a 40 mm interior diameter to fit an airsoft grenade?

What material, size and thickness of tubing (pvc, abs, copper) would be necessary to fit a 40 mm airsoft grenade inside of. It would need to be either 40mm exactly or slightly larger, although I'm not sure how much larger it could be.

Question by travisttt   |  last reply


Looking for Eagle file for standard breadboard power.

Hello;   I am trying to find an Cadsoft Eagle .brd file. I want to plug boards into a standard breadboard, for power. I want to plug onto the thin side. It seems to be a metric measurement, even though it is 0.1" hole spacing. Or if someone has the spacing info for the pins? I measured 4mm on centre, then 40mm to 51mm for the far row. So it would be on the left or right of the breadboard. I always round ground at the outside, and 5v in the middle. So swapping ends will work. Thanks, and I will keep looking Mick M

Topic by MickM 


Rate My EEE pc cooler

Hey guys what up this is my first post i wanted to know what you guys thought of my EEE pc cooler i made from an old mini cooler door lol . It has two 92mm fans on bottom and one 40mm on exhaust. i also over clocked my EEE to 1062 Mhz as well at a cool 47 C. can u guys add any suggestions and rate it out of 10 :) i think i should add a usb hub in the door on the right side. enjoy my pics

Topic by IIwootII   |  last reply


Metric Tube Supplier?

Does anyone know of any good steel tubing suppliers. I need a few different sizes, all of which cannot be found at any local hardware store, in square and rectangular shapes. Also, I found one supplier already and they had so many sizes to choose from. But they only ship large quanities to companies, not to the individual. So if anyone knows of any suppliers that can supply the following sizes for a decent price, your help would be very much appreciated. The sizes I need are 40mm square with 2.5mm wall, 25.4mm square with 2.5mm wall, 20mm square with 2mm wall, 40X20mm with 2mm wall, 35X16mm with 1.5mm wall.

Question by bombmaker2   |  last reply


I need help with a THERMOELECTRIC COOLER project?

My project I would like to complete is a thermoelectric piece of turbo piping to cool on my friends drift car it needs to be able to run on a 12v battery .I am looking at buying a few of these http://www.allelectronics.com/make-a-store/item/pjt-7/40mm-x-44mm-thermoelectric-cooler/1.html building a square piece of turbo piping to put it in. I am still not quite sure exactly how it works. I am a Ford Technician, Ford uses them in the heated and cooled seats so they kinda explained how they work but they left quite a bit out. So a lil info or suggestions would be appreciated thanks. If I build it I'll be sure and put the build up on here.

Question by j-rhod24   |  last reply


Having a problem with the new look instructables. Answered

OK this might get a little tricky to explain. At the bottom of the page we now have a grey section that contains a bunch of links/shortcuts or whatever. This is fine. At the top of the grey section is an orange bar with the instructables logo and the new fangled google custom search box and button. My problem is with the orange bar. On certain of my pages, specifically on my 'you' pages this orange bar appears about 30 or 40mm above the grey section. This varies from page to page, but seems to be worse on the pages containing the comments that have been made as a direct response to things I have written. As I advance through the list page by page, the orange bar gets higher until it covers stuff I am trying to read. This has been happening the whole time the pages have looked this way. Is this happening to anyone else? Is it just a bug? Is it just me?

Question by caarntedd   |  last reply


Need some help with Electromagnetic locks, LCD Screen, Smart card Reader and Battery Power!

Hi All, I am designing a locking device (see attached image) that will house a smart card reader, a small LCD screen (roughly 80mm x 20mm) and a small electromagnetic lock that will need to withstand reasonable force. The overall device will be no bigger than 140mm x 80mm x 40mm I would like to know whether a rechargeable battery would be able to power the LCD screen, electromagnetic lock and smart card reader. If so how big and what size would that battery need to be? How would an LCD screen be programmed to take information off of a magnetic strip and display it on the screen? I would also like to know some names for the components that would be required to operate all of these components. Thank you to anyone who comments. 

Topic by jonvjj   |  last reply


iPod Touch Rail Mount

Hey!I got a Roland V-Drum kit last year and there's an aux input for mp3 players. I use it with my iPod touch to play along with songs.My problem is, I rest my iPod on the control module and not only does this then block half the controls, but it sometimes falls off with furious drumming.So I though to myself, I wonder if I can buy a rail mount so I can have a cradel attatched to the stand. I knew you could buy motorbike iPod cradels, but all of these weren't wide enough to accomidate the 35-40mm diameter of the stand. So I thought about making one.But I can't come up with any ideas.The stand I have is this:http://www.woodbrass.com/images/woodbrass/BATTERIE+DRUM+ROLAND+TD+9+KX.JPG(not the drums though... I wish)The rail mounts I have been looking at are like this:http://www.mountguys.com/ProductDetails.asp?ProductCode=RAP-274-AP4&click;=21Any ideas guys?

Topic by Tibboh 


Where can i get furniture style pvc fittings in the UK?

I see so many good things about PVC pipe used for building things. In America you seem to be able to get lots of sizes of pipe and specialist fittings. In the UK  in bricks and mortar stores we are limited to just plumbing supplies. ie 21mm 32mm and 40mm pipe - we cant get corner 3 way fittings, 4 or  way, or any of the many pipe termination specials. I have a project in mind for which 25mm pipe would be ideal, but i need 5-way connectors, as well as some simple end teminations that push INTO the pipes not OVER the end. I have googled until my fingertips bleed but can only find this supplier in the UK http://www.ixi-devices.com/index.php/PVC-Structure-Connectors-Fittings-Clamps-and-Kits/View-all-products/Page-7 Frankly the prices are ridiculous - almost 6 times the equivalent US price - what goes for $1 in the states is around £4 in the UK thats just nonsense. Does anyone know any UK or even European outlet that will sell smallish quantities to me in the UK without these prices and without astronomical shipping and import charges? Help please.

Question by Brandlin   |  last reply


Need help sourcing a battery for my project?

I'm in the development stage for my next couple of projects, and after thinking about variables and other such random stuff, I've decided on a project (no, I won't tell you what it is. not yet at least!). The project is going to have to be very small, and will really be stretching the limits of through hole soldering (I dont want to to SMD on this). Due to size constraints, and power consumption, I need a very specific size battery. I need a battery with (I hope) at least 700mah capacity, if not more, as well as be rechargeable. Diameter should not exceed that of an AAA battery (around 12mm or so). Voltage CANNOT be 1.5, and must be more than 2v (single batteries only please! Multiple cell batteries are fine, as long as they are in a single package). Length of the battery can be pretty long, but should not exceed more than 40mm or so. Battery can be any rechargeable type, with the exception of Li-ion flat packs (I think they are a bit too fragile and volatile for a project exposed to daily wear and tear.). My current choice is a 123A li-ion 880mah battery, but it is a bit too wide for me.. Anyone know of a good, rechargeable, small battery? I know this is really stretching my choice limits, but I would GREATLY appreciate any help you give. Many, many thanks in advance,  -Thomas

Question by astroboy907   |  last reply


Problem with compressed air, ping pong turret

Hello all, I am in the process of making a ping pong ball turret powered by an air compressor, I’m using a solenoid valve to trigger the air electronically.i have had some exact diameter steel pipe milled out which is 250mm, so the diameter of the balls are 40mm and the diameter of the pipe is roughly 40.5-41mm. And I’ve sealed off one end with a tapped out hole for a nozzle fitting. My compressor goes up to 7 bar -around 100,psi -. Do finally to the topic 0f my question, i have tested the firing of the balls by firing 7 bar through an compressor gun, and to my surprise it didn’t fire across the garage like I expected, instead it made a very high pitched noise and the ball vibrated inside the tube, eventually the ball would rise up the tube and eventually speed up towards the end of the tube but still only launched at most 1 meter. Any help on how to fix this problem would be excellent. As I expect 100psi through an exact diameter tube would fire the ping pong ball very far. Feel free to ask any questions if I haven’t been detailed enough. Cheers

Question by bashmore00 


how to make a large wristwatch case?

I am a collector and amateur restorer of wristwatches and I have a couple of projects which require purpose made watch cases. This is because they are old pocket watch movements that are typically 40mm plus in diameter and in one case the crown is at 12 o'clock not 3 like a normal wristwatch. The standard OEM watch cases are generally too small and I am looking for something a little more elegant (but still masculine) to show off these beautiful vintage movements and dials (as such I intend to use a crystal back as well as front). I would like to do one of the watches with a yellow gold front bezel (if not a gold body) to set off the gold leaf/plate(?) numerals and hands (on a white dial). The body, lugs and back crystal bezel could be in silver (may even be preferable) as the exposed side of the movement is predominantly white metal with gold train and jewel holes. I have been thinking stirling silver for the main body and perhaps 18Kt gold filled base metal or solid 18kt gold for the bezel. I have no experience with jewellry making and would be very grateful for any suggestions regarding techniques that a keen novice could use to get a professional result. I would also be looking at jewellers screws to connect the 3 pieces. Just out of interest the second movement does not have a particularly interesting or aesthetically worthy dial so I am toying with titanium for the second project...........

Question by handles63   |  last reply


New washing machine waste pipe overflowing Answered

I'm the opposite of knowledgeable when it comes to plumbing however I have done a fair amount of searching through forums to find an answer to my problem and unfortunately still have questions. To make it easier, I have taken a picture of the pipes as well as the actual waste hose behind my machine. The hose from the machine sits in what I believe is called the standpipe on the left and goes approximately half a foot down. I have taken apart the p bend (or u bend - still don't know the difference) and confirmed that there is no blockage. I have run a snake down and around all the pipes with no issues and also used some soda crystals just incase but water flows through the pipes easily. What I believe is the issue is that the output from the machine is producing water faster than it can travel through the pipes which are 40mm in diameter. I believe that if I removed the p bend and just replaced it with a 90° corner, it would work fine but obviously it's there for a reason and particularly with the pipes only a 6 feet from the drain, I'm very reluctant to do that. One more thing to point out is that on the right hand side, there is a pipe which I have capped off. I was wondering if that trapped air could be preventing the water flowing down as quickly and if I need to find some kind of air valve which may allow air out? As it stands, I have just put the waste hose into the sink next to the machine and that has let me at least use it for now. I appreciate any advice people can offer.

Question by TheBag   |  last reply


Recommendations for mounting a 2.5" HDD in a small space

Hi, I'm currently trying to put together a small computer. I have a very limited space in which I can fit the motherboard and a few other components. Most of it kinda fits, but i'm not entirely sure how to mount the hard drive. The HDD is a 2.5" one like this one, with those dimensions: L:  100mm W: 70mm H:  8mm And once I exclude all the space taken by the other components, i have about that much space to fit it in (including the mounting parts): L: 170mm W: 40mm H: 75mm See the attached illustrations I made to get a rough overview of the space in the box. Note: I can technically extend a bit out vertically (height-wise) as the cover has a bit of gap inside but probably no more than an extra 15mm. The drive has screw holes on the sides and on the back (cf. the linked WD page) so there's a couple of options there. I'm not really sure how to go about this. I may be able to salvage some metal mounting parts from an old desktop but I would have to do some cutting to it and I don't have much room to move around for the mounting part. Another of my concerns is it'll be difficult to attach/remove the drive if I need to, because the bottom screw will be very hard to reach. Maybe there's a way to make a mounting rack where one part slides off to make the screws more accessible, I don't really know. Do you guys have any suggestions? How would you go about this?? I would much appreciate any tips, suggestions or even comments. Thanks Ben 

Topic by ben_dog   |  last reply


High efficiency coilgun design

Hello there I need some (a lot of) help with my project. I've started to design a high efficiency multistage coilgun. The main feature of the design is using the self-inductance formed in coils that were shut down for accelerating the following coils. To perform this, we can divide each coil into 3 segments (lets call them subcoils), connected with a wire and power all them 3 with a single capacitor. At first, the current from the capacitor is flowing through all 3 segments and a projectile is being pushed through the first segment. Than the first sensor is being activated with the projectile and it switches the power flow to only second and third subcolis As the current in the first subcoil is changed, the self-inductance directed in the opposite direction is appearing. In theory, we can use this power to increase the current in the following segments. The same thing is happening between second and third segments. And I want to place 3 of this stages (9 subcoils in total) I will use 8mm caliber projectiles, 40mm or 50mm length. I chose 5200mkF 450V or 6800mkF 400V capacitors, 2 of them in parallel for every stage (6 capacitors in total) Yes, I know it sounds way too powerful, but that's my actual goal. It's not my own idea. I have learned it from here http://gauss2k.narod.ru/adf/gs3seg.htm (русские вперёд). So, some problems had appeared. I can't figure out how to properly calculate the required inductance of the coils. In the source it is said that the inductance of the first subcoil should be equal to two of the second and the third subcoils (L1=2*L2=2*L3) to achieve the best performance. Also, my rough estimates show that peak current through the coil will be about 1,5-2,0kA for 3,0-4,5ms. This is quite a lot! I'll have to manage this energy and choose the power switches rightly. To sum up, I will be glad to hear your opinions about this idea. It's kind of controversial, but I hope it's not a certain failure.

Topic by CosmoKnight   |  last reply


Few questions about coil physics and capacitors.

Hello.  Hopefully there's some smart electromechanical and physics guys on this board. Long story short I have been working on a coil gun project for about a month now. Originally I was using disposable flash camera circuit, a simple push button, and a coil I took out of a fan. The coil itself is roughly 42 gauge wire, wound an inch long with about 14-18 layers. I achieved best results from this coil, about 4% efficiency, using a 200v 470uf capacitor and a magnetic projectile. However when I used a more powerful capacitor rated at 400v 820uf efficiencies were much lower. I realized the coil was limited and the capacitors energy wasn't being maximized. So I bought some 16 gauge magnet wire to wind a new coil. I wound a coil 40mm long, 3 layers thick around a 1 cm pvc pipe. The coil works but once again there is a huge loss of efficiency at higher energies.  So I need to wind a new coil.  Now here are my questions. 1.  I have read that a coil should be about 33% longer than the projectile.  Is this accurate? 2a.  Is there a magical equation to determine the number of layers a coil should have if all other factors are known? 2b.  How many layers of 16 gauge wire should I use for a coil wrapped around a 1/4 inch barrel to maximize efficiency with a 400v 820uf capacitor?  What about a 200v 1200uf capacitor? 3.  Could someone please demonstrate how to convert farads into amps? My main objective is an optically triggered multi stage coil gun with kinetic energy transfer of above 30 joules. I've moved away from flash camera circuitry and am now using dc to dc converters to charge the capacitors.  I need to find out how to convert farads into amps to figure out what kind of transistors I need for the trigger switch.  Any help is truly appreciated.

Topic by MurdaMastaMike 


Assistance needed for coil gun design. Any help appreciated.

Hello. Frequent reader, first time posing. I have been working a coil gun project for awhile now, nearly a month.  Originally I was using a pre made coil I took out of a fan.  The coil itself is roughly 42 gauge wire, with roughly 8-10 layers, and an inch long. At first I was using flash camera capacitors (300v @ 80uf) and flash camera circuitry to shoot a screw or nail through a pen tube. More recently I have been using a 12vdc to 120vac converter rectified to about 200vdc as a charging unit.  I also obtained some high voltage electrolytic capacitors (450v @ 820uf) that charge after about 2 or 3 minutes. After messing around with with the completed assembly, using a push button to short the capacitors across the coil, I realized that the wire coil itself was limited by its gauge and size and the full potential of the capacitors was not being maximized. So I ordered a spool of 63 feet 16awg magnet wire to make a larger coil for a more powerful and efficient design. So today I wrapped a coil around a 1cm clear plastic tube that was about 4cm long and 3 layers thick. The coil itself has a very low resistance. I hooked up a 200v 470uf capacitor to the coil and the charging circuit and when I fired my push button was welded shut. After that I was just shorting the capacitor across the coil to fire ferrous projectiles, which resulted in a rather large spark where I was shorting it. I noticed lower efficiencies compared to the other coil, which I'm sure has a great deal to do with the the energy the spark waste. So question number one: does anyone know what type of firing switch I would need to handle roughly 500 volts at 10(ish) amps and where I could find one. My objective is to achieve maximum kinetic energy with a 10mm x 30mm projectile. I have chosen to use a clear tube to eventually have a optically triggered multi-stage design. From research I have concluded that a coil should be 33% to 50% larger than the projectile, so my coil length has been established. I would like to know how many layers I should use to maximize the first firing stage with a capacitor rated at 450v 820uf and a coil that is 40mm long. Sorry for such a long post, but any help is greatly appreciated.

Question by MurdaMastaMike 


What components do I need to produce my 3 rechargeable Power-Packs using what ive collected so far ? Please can anyone help ?

Hello & Good day to you all, I'm making my own powerpacks for: a miniature wireless CCTV camera & receiver (Link Below for specs) , and a rechargeable powerpack to charge my laptop (that dies in 15minutes!) Wireless Pinhole Spy Camera & receiver After spending stupid money on sh*t 9 volt batteries (600mAh = £11 EACH) - ive had enough of the crap and absolutely absurdly LOW capacity 9 volt batteries out there (when TODAY's 'D' cell is capable of 11,000mAh !!!) and extremely high cost - i am making a battery-pack to power my receiver and another power-pack for the wireless camera using Ni-MH rechargeable batteries in the following packs: Powerpack 1 (for camera) 6 x 18650 cells @ 3.6v each, 5000mAh {Total Power=21.6v} Output Power Needed:  8v, 200mA Powerpack 2 (for camera receiver) 24 x D Size cells @ 1.2v each 11000mAh ( Total Power= 28.8v)  Output Power Needed: 12v, 500mA  Powerpack 3 (for Laptop) 40 x D cells @ 1.2v each, 11000mAh {Total Power=48v} Output Power Needed: 16v, 4A  I should add that my existing 9-volt (2 new & 1 old) rechargeable batteries are a little-more-than USELESS (Rated @ 175mAh...{USELESS}) as the receiver of my wireless camera drinks the power (juice, lol) at an extremely FAST-Rate... 15 minutes of use and its DEAD. 10 mins of use from the old 9 volt battery. And thats all from a 9 hour charge... How pitiful...Despicable & Disgusting... Now i got the idea to use a semiconductor from an instructable to make a simple solder-fume-extractor... (Link Below!) and also i know that resistors can reduce the voltage and amperage output of a circuit.......... Solder Fume Extractor I have calculated, researched, 'Googled', calculated again, more googling and after 6 months of trawling through the internet to find parts of designs i could hack together to achieve my goals including getting answers from "SO-CALLED-EXPERTS 'In the trade'" and from Circuitry & Electronics Forums (whom shall not be named...) yet they always say, yeah, here's my email address, email me your questions and when i do, they all turn around and gimmi some crap like "oh...well...you have your plan all set-out so what do you need me for ?" AS*HOLES! F*C*ING AS*HOLES!!! - If these peeps didnt want to help in the 1st place, then WHY BOTHER to give me their email address so i could ask them directly for help ? Im now going to give up and finally cry-out --- Please HELP (Again and probably for the last time!) ok ok, enough of the hell's-anger-fuelled-rage-at-"EXPERTS" who give me the run-around.....(Bcoz they're AS*HOLES...) Please please please can anyone help me find the components i need to make my very simple circuits for my battery packs ! I know that the use of a/a few? semiconductor/s (3 pin only) can let in a certain voltage and only output a specific voltage & amperage - i think i'll be needing a combination of a semiconductor and a resistor but i've searched continuous for 6 months now and am now irritated-beyond-belief that i still haven't found what im looking for or that no one is willing to help! ffs! Many thanks in advance for some light on this darn-troubling matter.... Please Help !!! Power-Specification For My Gear: Wireless Receiver: DC 12V 500mA Wireless Camera: DC 8V 200mA Sony Vaio Laptop 16v, 4A Also how do i charge my individual power-packs ? At what volts & amps do i charge them ??? Im already severely mobility-impaired and wouldn't want my life getting worse by any of my battery-packs exploding near me!!!!  Ingredients i have collected So Far: - 12 x 18650 5000mAh Batteries (Li-ion) (i want to make a total of two power-packs with these) - Solder Tabs for battery Packs -Small to medium collection of semiconductors + (plus) & - (minus) output voltages (from -24v to +25v) and from 100mA to 1.5mA amperage... - Heatshrink (40mm, 50mm, 70mm) - 24 x D cells @ 11000mAh - 40 x D cells @ 11000mAh I have no resistors but can order anything i need online if i only knew what to order!!! i would also need to include a circuit to prevent deep-discharge & over-charge! This is where i need the main help: I cannot read electrical diagrams at all but try to but it takes a day of deciphering and thats only if i do it right, i have dyslexia and am fighting daily with it when it comes to referring to any diagrams concerning circuits so would it be possible if someone could draw the circuits i need onto an a4 piece of paper and photograph it to be posted here (or draw it in paint, lol) - what i mean is, to draw a basic 3 pin semiconductor (a square with the 3 pins coming out the bottom, lol) and then draw the wires that need to connect to all the 3 pins to then for the wires to go to whatever component they need to go to next, for example ? {the 'solder-fume-extractor's' wiring picture where you can clearly-see where all the wires connect to all the components is the only type of simple diagram i can read by myself} Still wiht me ? i lose myself sometimes! So as i understand it, from what ive been reading so far, as long as the voltage output of the battery pack is correct, say for example for my wireless camera, if ive used a semiconductor to get the voltage of my power-pack down to give an output of 8v rated to 500mAh, as the device (wireless camera) only uses a max of 200mAh, then does this mean that the device will only use what it needs and ignore the rest ? Also it has taken a week of help from many friends of mine to help write this question and to keep it on-track with my main goals for the 3 power-packs listed above! if anyone needs more info, please let me know and i shall endeavor to reply as soon as humanly possible, again many thanks for your help Again, many thanks in advance for all help given and i sincerely apologize the long speech of a few questions, im afraid i get too-specific when asking for help (and often branch-off far-too-much, like now, lol)

Topic by offtherails2010 


Universal ultrasonic driver circuit - help required

I would like to build a few, properly working, ultrasonic devices.For example an ultrasonic soldering iron and an ultrasonic soldering bath.But some small ultrasonic plastic welder or cutter is nice too :)If you ever had one of the above to play with you know why they are great to have.The development story so far:I managed to destroy several driver boards.The ones you find for cheap with 28 or40kHz transducers in your favourite online store.In the beginning I knew I will have a need to repair or replace these boards but no clue why.Take an ultrasonic cleaner and read the manual.There it is always pointed out that a low water level can destroy your toy.What does that exactly mean?The transducer needs to be kept in resonance, if the water level is too low or something havy sits right at the bottom of the tank the frequency drifts off too much.Very expensive untis can cope a bit better here, which gave me the idea for the universal driver.During my experiments with hoorns I noticed that it is very hard to get usable results without extensive computer simulations first.Just one mm too long or too short and literally nothing happens, go a bit further and a thin aluminium horn might start to crack under the stress.And in all these cases the driver overloads, in one cheap case to the point that the transducer fused together.Trying to examine these driver circuits while they operate turned out to be a total nightmare!Place the probe from the ocsilloscope literally anywhere and the thing goes out of tune already.By the way: Never coil up the wires going to your transducer.....Only way I found that somehow works is by adding a tiny transformer around the wire going to the transducer and to measure the voltage generated there.To make it short: Destructive testing provided the requirements a driver needs to match to keep the cost low.Reasons for the premature death of cheap driver boards:Almost all of these cheap drivers I could find generate the 28 or 40kHz signal from the mains voltage.Means it goes through a transformer to get the desired 50-80V and some witchcraft turns that into a more or less smooth DC voltage.This is then switched by some beefy transistors, mosfets or similar, depending on the circuit.The actual feedback happens with a tiny ring toroid, similar to what you use to drive a ZVS system.With this dirt simple design a fully tuned transducer - like when nothing is attached to it yet - would cause the driver to provide a voltage of about 6x of what the transducer is rated for.Thankfully in most cases the transducer survives this a couple of times while the transistors fry within about 3 seconds no matter how good the cooling.Slightly out of tune - like when mounted onto a cleaning tank - the resonant frequency is slightly off the tuned 28 or 40kHz.The driver compensates this through the tiny feedback transformer.But this only goes for a about 1-4kHz, drift away further and first the power drops, then the voltage spikes and it dies.The feedback is not able to shift the generated frequency enough as it is ultimately derived from the mains frequency of your grid.Reasons why a dedicated, low cost driver would open new possibilities:Imagine you need to make a horn or sonotrode for your transducer.Knowing that each half of it should be equal to a quarter wavelength of the operating frequency is nice and easy.But if you add something like a blade for cutting or you need some pressure for welding then calculated dimensions become useless.Programs to fully simulate complex sonotrode designs, especially if you need to add screws or blades are costly and out of reach for most of us.Even if you would have access you still need to know the material properties to know the speed of sound in the material and how much it can flex in various directions without being subjected to metal fatigue.For basically all hobby needs in terms of ultrasonic gadgets we are happy with a simple push pull motion.the same motion our transducer offers by default.And when it comes to attachments it turned out that quite stubby horns of light weight are a good compromise already.A 50-50 ratio of diameter and length works reasonably well in most cases.For example the standard 40kHz transducer of 45mm diameter is quite happy to work with a horn like this:45mm diameter on the thick end, 20mm diameter on the tin end.Thick part 40mm long, thin part 42mm long.The extra 2mm are for the manual tuning by filing or sanding it off until there is good cavitation happening when you put the end into water.This however is only good for simple testing purposes and some fun but as soon as you attach blades or a small pot with about 200grams of molten solder the tuning is way off and destroys the driver quickly.To be able to deal with different pressure levels on the working end or just a different mass that is attached the driver needs to "know" the new self resonant frequency.Basic idea for a dedicated driver:Please bare with me on this one as my developing days got severly neglected once I moved to the other side of the globe....Input should from a 12V power supply, preferably a PSU to keep costs and sourcing time low.The operating voltage for the transducer shall come from a simple switch mode supply.I was thinking of scrapping a PSU for the transformer and switching transistor.This however would provide about 120-160V on 240V mains with the transformer of a PSU.To match the required load changes it would be great to drive this first transformer by PWM means to regulate the output voltage with a potentiometer while keeping it steady within the set values.Basically like every cheap phone charger but with an output voltage that can be adjusted and kept regulated.The switching transistors for the transducer should be well over the required specs of an out of tune transducer.I guess capable of switching 600V should be sufficient.Main design change to the cheap driver boards would be the feedback.A hall effect sensor could provide the proportional voltage to the current going into the transducer.It would also provide the real operating frequency of the transducer for the feedback loop.The resulting real resonant frequency of the running system is then used to drive the switching transistors.As a result the transducer would always be driven at the exact right frequency no matter the load on the working end.These transducers still have a quite limited frequncy range due to the fixed counterweight on the back - it is optimised to be self resonant without the transducer being mounted.To explain this feature let me use a spring with a weight on it....You can move your hand up and down to make the weight swing up an down with the spring force.You can also push the weight to get the same effect.But if the weight would just expand and contract there would be no change in the spring force or position or the weight.Our transducer however is mounted to something and the weight on the back is heavier than what is on the front end of the transducer.As a result the weight is pushed back and forth and because all is fixed together this movement is transfered to for example your cleaning bowl.Without anything attached to the transducer it would literally start to rip itself apart until either the bolt or the ceramics fail.The feedback loop needs to prevent this by adjusting the switching voltage going to the transducer.Once too far out the system needs to shut off until it can reset.The frequency control is not that fragile.With the power controlled through the feedback even a wide drift in the operating frequency of about 5kHz would only reduce the effectiveness and amplitude of the moving horn/sonotrode.Sadly my skill set in circuits is not that good anymore to have the required parts in my head and to know how to combine them properly :(Why this concept is only really good for really basic applications:Professional solutions utlise often less than 20W of ultrasonic power for a soldering iron or scaler.For these devices the sonotrode/horn is spefically designed for the task at hand.Same goes for any possible attachments - without them these things don't do much at all.Finding these low power ceramic transducer rings for a good price is hard enough, making an amplifying horn even harder.But when using these quite big 50 or 100W transducers we find for cheap online we can compensate the lower amplitude with the added power of the transducer.Since we only need surface action but won't have to go through a few liters of liquid it might even be beneficial.Fun fact: A 40kHz transducer has the second harminc frequency at about 170kHz.Means we could design a driver for the second harmonic and enjoy total silence when working with it.Would also mean that the ultrasonic power would be much higher.Mass times acceleration and such things ;)If you want some ultrasonic cutter then you don't want to waste weeks and lots of money trying to come up with a working attachment to your transducer.Just keep it as short as possible and with about the same weight as the front part of the transducer.At least the driver desing would make it quite easy to design an amplifying horn by trail and error through reducing the lenght of the thin end until it really fits.Anyone with good circuit skills willing to volunteer? ;)

Topic by Downunder35m   |  last reply


Ultrasonic soldering bath

Making a working ultrasonic soldering iron is not as easy as I though it would be.Finding tanrsducer of suitable design and size is even harder.So I thought I start with something easier and share the thoughts here.If you need to solder impossible to solder things then quite often you could get away by wetting the entire area.For example the end of a wire or a lug where it won't matter that you can solder on the bottom as well as the top.Back in my days flux core solder was a rare and very expensive thing to find.So we had a little soldering pot and flux pot instead for working with lots of wires.Dip, dip, done....The pre-soldered wires where then easy to work with and the ramaining flux on then was enough.Doing this for metals like aluminium, stainless steel or even ceramics seems impossible at first sight.China offers cheap ultrasonic transducers including the required driver electronics for very littel money these days, despite the trade wars.The most obvious solution would then be to get a cheap and big enough soldering bath and to attach the transducer to it....Won't work though and if it does then not for long.Problem is firstly the heat transfered to the ceramic parts of the trandsucer and secondly the fact that most of these soldering baths use quite thick steel for the container.Add the that you deal with quite some grams of molten metal and you know where I am going.Building your own ultrasonic soldering bath to solder the impossible with ease!Project costs:40kHz transducer with driver board : about 50 bucks.Thin walled stainless steel bowl ( about 50 to 100ml but go bigger if you like) : about 2 bucks.Leftovers for an enclosure can be wood, plasic or your favourite 3D printer.Ultrasonic horn: About 500 bucks from your favourite engennering company or you need to make it yourself - I prefer the later.Main design considerations for the horn:We need something to keep the heat away from the transducer that also amplifies the power coming from it.That is why we can use a bowl or container that has a small bottom daimeter as the transducer if need be ;)There is a good reason a commercial horn costs a lot of money.They are preferably made from titanium and they need to perform as advertised right from the start.We substitude by using some aluminium round stock and a lathe.It is advisable to leave the transducer as it is!Do not take it apart to mount your horn directly onto the ceramics!Use a long enough set screw or include the required thread on your horn to mount it onto the transducer.If you prefer to use stainless steel doe to the lower heat conductivity then be my guest.The horn should have the same diameter as the mating part of the transducer for a quarter of the wavelength of the transducers frequency in the given material.Please look up how fast sound travels in your choosen material and calculate it properly.Having the lenght of the thick part right is quite cruicial.The thinner part that amplifies our movements should be about a quarter of the diameter of the transducer.For example: if the mating face of the tansducer is 40mm in diameter then the thin part of the horn should be 10mm.The length again is a quarter of the wavelength or the same as the thick part.Where thick meets thin please allow for a 3 to 5mm radius and make sure this area is nice and smothly finnished.Now, length is quite critical here....As we will mount our finnsihed actuator free hanging under the bath we need a feasable way to comapensate for our tolerances by creating our horn without a simulating software. I found that welding a short stub onto the container works best but with aluminum it is harder.I assume most will opt for welding a 6mm soft steel threaded rod onto the container.Either way the container surface must be kept flat for the mating surface of our actuator rod.So it is best to make the stud yourself or to use a suitable replacement - like using some flux and your stick welder for create a makeshift spot welder ;)If you decided on using steel for the horn then of course you can just mill a 10mm piece with a suitable thread and flat mating surface...What you want to end up with is a screw connection that has a flat mating surface and no empty spaces, fine thread prefered.Tuning the horn....The ensclosure is easy to make as a box, so the only thing to worry about is insulation but nothing to affect performance.So I just assume you have it all ready ;)With the horn at one quarter wavelength either end our thin end will be too long unless a short stud is used for a direct fit.So whatever you had to add for the part on your container or bowl need to be removed from he horns thin end.Try to keep the gad for the threaded part as small as possible as it affects the resonace.As things never turn out perfect the first try I prepare some thin steel washers - 100mm outer diameter in case you wonder and stick with the above example.I use a strong neodymium magnet and belt sander to create washers from very thin to slightly thinner ;)Taking off slightly more from the horns end will then allow toadd these washers if required - but please do a try as it is first when you think you got the measurements all right!For an aluminium horn you will of course use aluminium washers here.To do so fill the container with some water and place a sheet of thin alumiium foil on top of the water.Turn it on and within a few seconds you should see holes appearing in the fiol or even small fractures.If nothing but noise happens it is quite certain your rod will be a bit too long.Unscrew and take about one tenth of a mm off the thin end of the horns mating surface to shorten it.Try again with the foil and if no better remove some more material.Once you see some action try adding a layer of aluminium foil between the mating surfaces - screw it tight!The foil won't last long but if the action on the water is far better until it fails you know you took off too much.The washers come into place if the tuning won't work at all.Sometimes you can cut off a little bit again and again but the piece will remain too short ;)Especially if you have an aluminium horn and needed to use a steel screw on the bowl...So once the shortening of the horn fials you add a washer to get slightly above the original length and start replacing the differently thick washer until you find a sweet spot.The tricky part is over, now to solve the heating poblem...Using some glass seal as used on wood fire ovens not olnyl provides good insulation to our enclosure but also prevents the vibrations from spreading too far.As our hardware store won't just give use the little bit we need the rest can be used to insulate our container.Dending on the size and shape of your container I hope you decided to buy a container tha fits your heating element...I found that replacement coils for lab heaters work fine but some small fan heaters also use round heating elements instead if wire spirals.For a custom shape it is quite easy to use a coil of heatin wire rated for your mains voltage and a glass fibre sleeve for insulation.To keep it all in shape just wrap some steel wire over it - over the insulated coils of course.The temperature control can be as fancy as with a microcontroller or as simple as using a dimmer like I did.Most heating elements will go glowing red hot if the mains voltage is not reduced.It makes sense to limit the dimmer's movements accordingly by testing it.Just do it in the dark afeter exposing a small bit of the heating wire from the insulating sleeve.Once you see a faint glow coming dial it back a bit until you can see any glow - that should be the max setting.For a big bath or to save time you can of course crank it up to what the glass insulation can tolerate but be aware that solder can boil over!I do a temperature check either with a touch free IR thermometer of by checking how quickly some rosin boils off.If you need to dip bigger parts you need a higher temperature, so I think a digital or sensor temp control is not really required.Once you found a sweet spot to hold the solder temp long enough without getting too hot or cold just mark it for reference ;)Using the ultrasonic soldering bath correctly.Cavitation is what the work for us, so we only need to activate the ultrasonic part when we need it with a push button or food pedal switch.We do not use any flux or resin!That means if you used the bath for normal soldering and or resin then clean the remains off the surface first.A shiny and clean surface is best but the oxidisation will happen quickly so don't be too disappointed ;)Start by dipping in a clean copper wire.Some solder might stick but it won't look proper.Now dip it in again and while it is in push the button for about 3 seconds.Like magic, if tuned properly your wire is soldered and properly covered to where it was dripped in.Try the same with some slightly sanded or at least clean aluminium wire, but use the button right away for about 5 seconds.The wire should be coated with solder once more.You can try a glass rod or some stainless wire next but I guess the working principle is clear now ;)Not everything will bond with solder, especially not if it is not clean.A piece of glass with your fingerprint on it might just fail and some ceramics will only let the solder stick without actually bonding.You should always check the mechanical strength of your soldered connection before having to rely on it ;)And why would you need such a machine?Well, most people won't have any use for it.Those who do might not be able to afford a commercial model.And there is always those who just want it all...If you know why you need such a thing than you have an alternative now at a fraction of the cost.You only need a lathe or someone who can machine the horn for you.Another benefit is that for smaller containers it is possible to weld a small "bridge" over the top.Should be placed so the bottom is in the solder while top is above it.In many cases you will then be able to use this plate to heat up whatever you need to solder on.Like a glass plate where you would like to solder a wire to.Once up to temp turn the ultrasonic part on and use a normal soldering iron and flux flree solder.Works quite well for these small solar panel kits...Ok, and how far away is our cheap ultrasonic soldering iron?Not that far :)I already have a topic for this though....

Topic by Downunder35m   |  last reply