Making a Memristor (a tutorial...sort of) - Page 1
Forum section: electronics / projects

author: Maximus
author_rank: Contributor
timestamp: November 08, 2013, 05:53:15 am
content: Howdy!I have been working on making some memristors so i can do some experiments on them. I think i have finally managed to make a memristor. If i understand properly, memristors are characterized by their pinched hysteresis loops, their ability to "remember" their resistance.A memristor I-V curveI thought that it would be a good idea to get some others opinions on weather or not i have actually made a memristor.I will start with a quick explanation of my methods for creating a memristor.This:Is my memristor.Anyone familiar with firearms will notice that it is built inside a 0.22 cal. casing that is now very blackened. don't mind all the other stuff on my bread board, it isn't relevant.The black stuff is Copper Sulfide(i am terrible in chemistry so if someone out there knows what this really is please tell), this is the stuff that makes all the magic happen. Before you blacken the cartridge you first have to tin the bottom where the firing pin hits the bullet because it is difficult to solder a wire onto the black stuff.Back to the Copper Sulfide. It is created when i filled the empty cartridge with sulfur powder and heated it up until all the sulfur is burnt away, do this with safely the vapors from burning sulfur are horrible to breathe.Next I strip about 1" of insulation off a piece of 22 AWG wire and wrap the uninsulated part around a small screwdriver 2 times to make a coil that just fits into the casing. While keeping gentle pressure on the wire taking care to only let the wire touch the bottom of the casing i filled the remaining space with epoxy. After the epoxy has dried your memristor is ready to go.I have several I-V curves from my memristor:It turns out making a memristor has been fairly hit and miss untill i perfected my method. This is a typical trace of my early memristors. Not quite the perfect figure 8, and it has two points where it crosses itself. Alot of the time I would get a flat line (open circuit) or a vertical line (short circuit).Ocasionally i would end up with some strange capacitor-like trace.After lots of work, it all payed off and I got this traceIf I'm not mistaken that is the trace of an ideal memristor.Out of curiosity i put a 100Hz square wave through my memristor and was rewarded with one of the most interesting traces I have ever seen.So that's my memrisor. Here is the whole gallery of images.http://imgur.com/a/ER89YFor anyone looking to recreate this experiment, you can talk to your pharmasist and ask them to order you "Precipitated sulfur". It will be less than $15CAD for half a kilo of it(enough for 1,000,000 memristors).I look forwards to your thoughts on my project.also First Post! yay.I would like to credit this web-page with the basic idea of how to make this type of memristor.http://makezine.com/2011/11/03/how-to-homemade-memristor/

author: BravoV
author_rank: Super Contributor
timestamp: November 08, 2013, 08:28:53 am
content: Interesting experiment, thanks for sharing !

author: Whales
author_rank: Super Contributor
timestamp: November 08, 2013, 10:14:48 am
content: Indeed!Plecos for sharing -- I'm going to have to try making my own now. To the crusty sulphurous deposits!

author: clifford
author_rank: Regular Contributor
timestamp: November 08, 2013, 12:11:27 pm
content: Wow! Really cool!I've googled a bit but haven't found much about this type of memristor implementation. Can anyone explain how it is working? I'd assume it is some kind of electro-chemical process?

author: Maximus
author_rank: Contributor
timestamp: November 08, 2013, 03:13:05 pm
content: Quote from: clifford on November 08, 2013, 12:11:27 pmI have access to quite a large database of scientific journals (especially electrical engineering related ones) and whatnot with my school. I will give that a look-through today and start hunting for a reason for why these memristors work.

author: Tinkerer
author_rank: Frequent Contributor
timestamp: November 09, 2013, 12:34:41 am
content: Whoa, its only been in the last couple years that they have been able to even take the memristor from concept and math to reality. To be able to do this on your own is impressive.In regards their ability, yes, they are supposed to "remember" all previous resistances. Hence their name.

author: amyk
author_rank: Super Contributor
timestamp: November 09, 2013, 02:27:41 am
content: This is impressive, on the level of making your own transistors

author: c4757p
author_rank: Super Contributor
timestamp: November 09, 2013, 02:31:58 am
content: Anyone who can make their own components gets serious points from me. I've been meaning to try to make a transistor at some point, myself, but it's hard to find the time.

author: Maximus
author_rank: Contributor
timestamp: November 09, 2013, 06:42:33 am
content: UPDATE:It appears that the type of memristor i described is doomed to an early death. This manufacturing process creates memristors that slowly decay into regular old resistors as they are used. To make a more durable memristor we would need to expose a piece of copper to H2S for half a day. Unfortunately H2S is super poisonous and likes to explode. So until I can figure out a safe way use H2S I am stuck with my temporary memristors.Sources:Memristors based on an organic monolayer of molecules and a thin film of solid electrolytesIslam, M.S. ; Johns, C. ; Long Do ; Ohlberg, D.A.A. ; Shih-Yuan Wang ; Williams, R.Stanleyretrieved from IEEE Xplore

author: BravoV
author_rank: Super Contributor
timestamp: November 09, 2013, 08:19:28 am
content: Apparently you didn't pay attention to the absolute maximum ratings from the manufacturer of that poor memristor.Seriously, if you're going to make new one again, please, do a complete step bt step documentation like photos on each progress, imo, that will be really helpful and much less trial & error for other people to follow your steps.Great thread, bookmarked & subscribed.

author: Len
author_rank: Frequent Contributor
timestamp: November 09, 2013, 09:48:06 pm
content: Pls post datasheet kthx.

author: Tinkerer
author_rank: Frequent Contributor
timestamp: November 10, 2013, 01:27:46 am
content: Quote from: Maximus on November 09, 2013, 06:42:33 amWell, the safe way here is to use tha standard basic precautions you should take with chemicals and then use a very small amount and allow it to sit somewhere it wont be disturbed. There should be guidelines written on safe handling of various chemicals out there.

author: Unknown
author_rank: Unknown
timestamp: November 10, 2013, 08:02:12 am
content: Quote from: Tinkerer on November 10, 2013, 01:27:46 amIn the case of H2S, the handling and storage guidelines are basically "don't - unless you have the facilities, are well trained, really really have to, and have a spotter who isn't going to run in and become casualty #2 if you collapse".It really is nasty stuff - not the least because the threshold for detection (i.e. you smell something odd but can't recognise it) is in the sub-ppbrange; you can become temporarily desensitised to it and fail to recognise the smell from a few minutes of exposure at sub-recognition levels (a few ppb); it can knock you out almost immediately at a few hundred ppm; and less than 1ppt is considered lethal.About 2/3rds of people who are killed by H2S die because they figure "I can't smell it any more, it must be safe", and wander in where it's a bittooconcentrated. Most of the other 1/3rd die when they rush in to help their mate from the first 2/3rd who passed out.Oh, and it works in much the same way as cyanide.It might not be up there with polonium, things with lots of nitrogens in them, or dimethyl-justaboutanything, but it's certainly not something for even an experienced home chemist to deal with in any quantity bigger than found in a dodgy egg.

author: Tinkerer
author_rank: Frequent Contributor
timestamp: November 10, 2013, 09:43:57 pm
content: I had a longer reply on enclosures and gloves and what not, but really at 1ppt dangerous, I would just find a lab that can help.

author: Maximus
author_rank: Contributor
timestamp: November 11, 2013, 04:46:35 am
content: Maybe I will send a few memristors to Dave for Mail Bag Monday.

author: Maximus
author_rank: Contributor
timestamp: November 11, 2013, 06:43:21 am
content: Quote from: StevenWhitney on November 11, 2013, 06:13:56 amThere shouldn't be anything wrong with it. May set off some sensors that sniff for gunpowder? Maybe i could get the post office to check the package at the office to give it a 'passed inspection' stamp or something.

author: branadic
author_rank: Super Contributor
timestamp: November 11, 2013, 11:18:20 am
content: Hi,as far as I understood what you need is the oxid on the brass, that can be made with any other process too. Your arrangement is close to the printed Cu/CuO/(AgO)/Ag memristors made by several other groups.What you have here is brass/brass-oxid/(AlO)/Al and brass is based on copper. You might get better results using copper instead?branadic

author: Maximus
author_rank: Contributor
timestamp: November 11, 2013, 11:04:15 pm
content: Quote from: branadic on November 11, 2013, 11:18:20 amAs for the oxide:I have tried using copper oxide for my memristors in the past. This was actually one of my first experiments I did while waiting for my sulfur to arrive. I created a little point contact junction between a penny(1/100$ Canadian coin. They are copper plated.) that i had oxidized by heating it up, and a piece of aluminum.(sorry queen Elizabeth II but i need to melt your face off for science)The plastic card insulates the penny from the aluminum i built the rig out of. any part of the aluminum is one contact, the red wire is the second contacthttp://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCoQFjAA&url=http%3A%2F%2Fanswers.google.com%2Fanswers%2Fthreadview%2Fid%2F397640.html&ei=7-KBUra9OqXhyQGZwYCwAg&usg=AFQjCNHPD-Ow_r90QZDXkb2FAcKueii5ww&bvm=bv.56146854,d.aWc&cad=rjathis page has some useful and interesting information about the conductive properties of copper oxidesIt did work but I found that the copper oxide liked to scratch off and it seemed to have the same problems with limited lifespan. Obviously more research, and more detailed documentation is needed on my part.As for the Brass:You may be right on that one, for some reason i thought the casings were all copper. It appears that either:A) brass doesn't have a serous effect, as the memristors all work great.B) the casing is, in fact copper-----------------------------------------On a different note I have briefly looked into simulating memcapacitors and meminductors using a differential amplifier and a memristor.This is all very exciting and i think it may be time to make a separate webpage or blog or something of my own about all these memory components so i stop clogging up this forum.I imagine that memcapacitors would have some interesting applications in some sort of programmable RC circuits.lots of fun stuff to learn about, i hope everyone finds this as fascinating as i do, i do realize its more into the physics/chemistry branch of things rather than the engineering.

author: branadic
author_rank: Super Contributor
timestamp: November 12, 2013, 07:48:01 am
content: QuoteAre you sure? I would have said it's copper oxid, copper sulfid is green (green rust), isn't it?QuoteSorry, I confused that with the "How-To: Homemade Memristor".Anyway I think your arrangement is similar to the one of Nyle Steiner, but instead of brass you used copper --> Cu / CuO / AlO / Al.However, I expect a similar effect to what is published for the printed memristors. The different is, they can't print aluminium, so they used silver instead.http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=06553043