As each year passes and my to-do lists get longer, I have to accept that I will die long before I will get to make and do everything I want to.
Here are some things that I probably will never get to, but maybe you will? Don’t let the crackpot-stream-of-consciousness-style throw you, I believe most of these ideas could actually be successful and profitable… with some work.
Let me know if you are truly interested and I will try to share any effort I’ve already invested to give you a head start….

Supercheap backwards-proof coin cell holder
You have to make sure that things will not burst into flames when a user puts in a battery backwards. This typically involves protection diodes or transistors, but these are extra parts, points of failure, and hurt battery life. I’ve seen holders like these that are reverse proof…


…but they are complicated and crazy expensive.
I think you could make a really cheap one out of a single piece of stamped steel that had some little ears on the sides and some strategically applied paint or plastic film on the inside top to prevent the ‘-‘ side of an improperly inserted battery from making contact…


Also see the little finger window so you can easily push the battery out? It is such a pain to wrestle batteries out of the holders I use now.
To get the price right, you would have to make millions of them and get people to use them, which would likely require getting UL to say that they were good enough reverse protection to depend on for certification.
If you make this then I will be your first big order!
Tree-based problem management
When I am working on a problem, I almost always use the same strategy – I think of all the potential solutions to the problem and then start to think about what problems I might have trying to implement those solutions (repeated recursively). It becomes a dependency tree with a problem depending on solutions, which themselves depend on problems, etc.
Let’s say that Solution A depends on solving Problem X and Problem Y. As soon as you discover that Problem X is not viable, then there is no reason to work on Problem Y. You can also give up on any higher up problem that depended on Solution A. Similary you can have solutions that depend on solving Problem X or Problem Y, in which case solving either means you do not have to look at the other or anything below it… and any higher or’s that depend on solution are also completed.
This sounds almost trivial, but for actual hard problems these trees can get very complicated, and it is easy to get lost in trying to solve a sub-problem and forget all the other contingencies on that solution.
I think you could build something like this in JS or even Bubble pretty quickly. It could be totally graphical, and I love the idea of seeing that there is actually one critical problem down towards that bottom of the tree that, once resolved as either solved or not viable, would immediately shrink the problem space in otherwise unexpected ways.
I can’t tell you how much time this would save me, and hopefully promote this problem solving strategy to others.
Skyhook ladder stabilized by reaction wheels
A ladder that you do not need to lean up against anything. Think really tall Segway that you can climb up. So many times I’ve needed this!
You could also make a great straight-up selfie camera pole.
Isolated Wifi base station as a product
This is a Wifi access point that it not connected to the internet. Instead all content is served locally, and it acts as a captive portal to any devices that connect to it.
The poster child use-case would be to put one of these in the middle of big park with no cell coverage. The default splash page would be a map of the park, and it would even show the user where they are on the map using a JS location API to get GPS from the viewer’s phone. You could also see where all the other people connected are (or recently were) and easily send messages to them (either real-time, or store-and-forward, or public bulletin board style). There would be a guest book you could sign and lot of other useful information (remember there is no cell coverage here). Maybe even an SOS button with a back-haul to the ranger station that also uses your location.
For hardware, you could using an existing cheap and robust off-the-shelf outdoor AP (like this) connected to a solar panel and battery sized for the location. There are some tricks you can do to make this super cheap and easy to flat pack too.
Most of the tech for this project is done, it is really about adding polish and making it into a real, supportable product. It would probably would make sense to start as a kickstarter. I think there are so many people who could use this for cool stuff.
And I’ve left (I think!) the best part for last…. I think there is a trick we could use to let people use this completely isolated AP to actually get messages out to the internet – albeit with an indeterminate delay. On the AP we send people to a real domain and make it look like we are really at the right IP address with our embedded DNS server. We use the real certs for the local website, so as far as the phone can tell they are really connected to the real deal so it is happy to accept cookies from us. Inside these cookies we store compressed and encrypted outbound messages. Now when that phone eventually gets back to civilization and goes to the internet connected server at the same domain we were faking, it dumps these cookies up to the server. The server decodes and forwards them on their way. The server can also drop some cookies to let the isolated server know that the messages got passed just in case that phone ever goes back to the park. We’d also possibly get a back-channel if people who are planning a trip to the park went to the internet-connected website before they left.
Make a building that (seems like) you can move it
You know optical illusions? This is more of a touch feedback illusion.
I once just happened to bump hard into the sink in my bathroom at the exact moment that the toilet tank rocked because it was done filling. The effect was powerful- my brain was certain that my bumping the sink had shook the whole building. It took several seconds for me to figure out what had actually happened, during which time I was wonderfully bewildered.
It would be easy to set up a room where things would be able to detect when they were bumped. Hard bumps would use actuators to cause other movable objects to react as if the building had shifted.
If this was on a high floor of a tall building, I think it could be a compelling tourist attraction. I’d sure pay to have that feeling again!
Hand of god
Roller coaster meets skydiving meets white water rafting down the grand canyon.
I’ve been dreaming of jumping off the top of the Grace Building since I was a little kid. It always seemed like the curve would catch me like the hand of god.

I’ve love to build a giant stainless steel parabolic curve. Really giant, like hundreds of feet tall. The curve would be vertical at the top, gently becoming horizontal by the bottom. It would “catch” you by directing your downward motion into forward motion. At the top you would be in free-fall, at the bottom you’d be on the fastest county fair slide ever.
The joints of the panels would be stainless steel and lapped like roof shingles so there was nothing you could get caught on. Everyone would wear a full coverage Tyvek suit and a motorcycle helmet so no part of you would ever touch the surface.
Ideally, you would want to build this against the face of an existing cliff. It would be wide enough that lots of people could all use it at the same time (not narrow like a slide).

At the top, you would run as fast as you wanted to towards the edge… and jump off into oblivion.
Besides the thrill of repeatedly jumping off a cliff without a para-shoot, I think this monumental gleaming mirrored curve in the middle of a landscape would be a thrilling spectacle just to look at!
For whom the bell tolls
Public art project.
Do it on a long dock into the river, like the docks that reach into the Hudson on NYC West Side. Nautical bells like the bells on the passing ships. Bells line both edges of dock. The sweet spot is at the very end of the dock. As you start walking down the dock, the bells sound totally unsycnhronized, but they get more and more in sync the farther you out you go. The bells are carefully timed so that when you reach the very end of the dock you hear the wavefront from all of the bells arrive simultaneously (with some cool frequency spreading). The bells toll for YOU.

Each bell is maybe triggered by the arrival of the sound pulse from the previous bell, so temperature and wind effects are automatically compensated out? If not, then brute force it with an RF sync pulse and an Arduino calculated delay. Each bell station is solar powered with a local battery so setup is easy (no wires).
This could also work in a big field with the bells randomly scattered about. Maybe you do not tell people where the focus point is – they have wonder around and happen on it by chance. Moving the point around (by changing the delays between bells) keeps it interesting. Maybe a scene camera picks one person every 5 minutes and they are always the focus wherever they go.
The Rabble Rain Room
Rain Room is cool, but not worth $40.
Let’s make a rain room for the rest of us! And make it better (bigger,denser, more responsive, silent except for the rain) than the real one!
Use electrostatic valves with no moving parts to make the super cheapo rain headers. Use direct laser breaks to sense where the people are (know what you are thinking, but you are wrong). Get a trash pump and some PVC and bob’s your uncle.
This one is basically done, you just need to set it up someplace and tell people where to come!
Electrostaticly accelerated abrasive cutting
Water jet cutters use water to accelerate and carry the abrasive to the workpeice, but it is messy and imprecise. Instead, electrostaticly accelerate a stream of abrasive particles directly. You would likely need to be be in a soft vacuum, but the payoff is an extremely thin and accurate kerf- almost as thin as the individual particles. Kinetic energy at impact is almost unlimited, and you could use a multi-stage barrel like in rail guns to avoid super high voltages.
Potential nice side effect- charged abrasive particles repel each other so maybe an easy way to have uniform dispersion and declumping.
Back scratching machine
Why don’t we have a machine for the one thing we can’t do for ourselves?!
The tech is easy, but this would take some serious (but pleasant!) R&D to really nail what pressures, tip types, and motions make for a great back scratch – and it is likely you could ultimately produce an experience that was, at least sensually, better than any human backscratcher.

Great kickstarter, and ultimately would be a long returning product.
CNC in an Altoids Tin
Make a CNC machine that used EDM to remove the metal.
The conductive blank would be immersed in de-ionized water inside the bottom of the tin and the tip of a hypodermic needle would trace out the “cuts’. Continuous flow though the needle would wash away the spoils. Careful control of the needle height would make for thin kerfs. The needle could be automatically electrochemicaly sharpened periodically.
Since there are almost no forces on the tip, the actuators can be tiny. It would be slow, but who cares – leave it running all night.
This would be a home run kickstarter, especially if one of the demo projects was someone who made their own mechanical watch on it.
EDM PCB cutter
I have an OtherMill for making printed circuit boards, but the accuracy and minimum kerf size limits its use.
Use EDM like in the above project with a very pointy hypodermic needle. Super slow, so only suitable for Voronoi and isolation paths, but oh the accuracy and tiny feature sizes you could do! OMG, the RF circuits you could make!
For sure there is only a limited market for this, but I PROMISE that you’d sell at lest one… to me! Maybe Bre will buy your company too. :)
Consumer desktop wire bonding machine
Once you have an EDM PCB cutter, you’ll quickly loose patience with all those giant SMD packages. WLCSP all the way baby, but how? Flip them on their backs and wirebond them directly to the board! I have a wire bonding machine and I can’t imagine how anyone lives with out one… except that they are huge and cost so much. But they don’t have to. I bet you could make a consumer grade one for a couple hundred bucks if you put a little time and effort into it. The tips (“tools”) are a commodity, and the rest is just a lot of low tech stuff that has not been optimized in decades.
Electrolysis desktop fireplace
An ever-burning, sealed combustion, electrically powered real flame.
Start with a small hermetically sealed glass chamber filled with ionized water. An induction coupling powers some long lasting electrodes to generate Brown’s gas, which is collected and artfully conducted to a combustion area. The atmosphere inside should include something to “soot” and make the flame glow with the traditional oranges and yellow (plain hydrogen flame does not look like a fireplace fire)? The condensate is discretely collected out of sight and infinitely recycled.
The tech here is important, but the design and form factor will make or break this as a product. It really needs to be gorgeous.
Oh, and keep it small to make sure there is never too much H2 in there! Wow that stuff blows up good!
Perfect Kickstarter home run if done and sold artfully.
UPDATE 2/1/2021:
Not practical for home use, but cool…
Building a Wireless Power Plasma Candle ( Flame Discharge ft. Teslaundmehr)
https://www.youtube.com/watch?v=SyZuel2iaBk
Low cost microfilm service
There are lots of ways to back up data efficiently and cheaply, but all require that you have a computer to access the restored data.
Make a service where users upload a bunch of PDFs and then they get one of these in the mail…

Sure it is a novelty, but also could be actually useful. Come on, I bet you have 20 pages of documents that you’d want in your pocket when a zombie apocalypse (or EMP pulse?) hits, right?
This is mostly about setting up the website and marketing, making the actual films is 50’s tech. I’ve even been able to fit a page of text into a 1mm square by just pointing my old skool Nikon FE2 at a monitor on the other side of a dark room, and I haven’t even tried the good stuff yet.
But maybe once you get some traction, it turns out that there is a real market for no-computer-needed high density backups. Really. Then you get to buy one of these and offer 0.000283465 point text output! :)
UPDATE 2/1/2021:
The always awesome Ben Krasnow is all over this. I bet he is working towards making lithography masks…
https://twitter.com/BenKrasnow/status/1242692827491917825
BTW, I have since gotten an old school film recorder which is very cool and I bet I could get >10K lines out of it using an Arduino to control the CRT.
OrsonEar
Contemporaneously transcribe everything you say and hear. Search for things in your conversations as easily as you search for things in emails.
Thanks to all kinds of laws, you just can’t go around recording stuff. You’ll eventually go to jail. Thanks Nixon.

But it seems that there are no laws against contemporaneously transcribing everything.
I’ve been working on this for 20 years, but the tech to make it really work has finally arrived. As of like yesterday, this is now almost trivial to do.
I got pretty far in the past. I actually have a legal opinion that this is kosher. I also have lots of geeky equipment… that is likely no longer necessary (just use Bluetooth headphones or leave your phone in your breast pocket). I even have the domain ready when you are.
Electrostatically driven heat pump windows
Fill the sealed space in between window panes with a permanently ionized gas.
Electrostatically make the gas oscillate between the two panes such that it is alternately compressed against one pane and then allowed to expand out towards the other.
The glass on the compression side gets a little warmer, the other side gets a little colder. You have an efficient heat pump with no moving parts and lots of surface area, exactly where you want to sink and source heat – at the building envelope.
Maybe coat the panes with ITO to make it work. You’d need a layer of insulation between the ITO and the gas to keep it from deionizing, so maybe a thin film dielectric on top. Heck, you are depositing low E films on the window anyway, right?
If it turns out to be hard to keep an isolated gas ionized for a long time (is it? Please tell me!) you could maybe put a catalyst in there to make more ions with solar energy, or just use an old skool a pointy electrode.
Bounce the gas at resonant frequency for best efficiency. Pick a gas and a chamber width to be sub-audible or ultrasonic otherwise you’ve just made an awful one of these.
High efficiency inverter window AC unit
These days you can get the most amazingly well designed and built ductless mini split heat pump systems. They use inverters to run the compressor to exactly meet the load. The compressor is soooo quiet – and it is outside where you wont hear it anyway. The inside fan coil is nearly silent.
But, alas, the smallest one is too big for NYC apartment dwellers- and a few billion other urbanizes in hot cities around the world.
Basically take a minisplit and shrink it down to fit in a window. Have separate fans so the only stuff that runs between inside to outside are the two refrigerant lines and a condensate drain. These pipes are only 1″ high so you can run them in a flat pan. Hey, now you can close the window almost all the way with the AC installed! Now you really can’t hear the (already very quiet) compressor outside.
Mount the compressor BELOW the sill so it does not block the view of the outside. This also makes is possible to use gravity to drip the condensate down onto the condenser coils. Remember that water is cold and wet, so the coils run so much better- ask any giant facility that sprays water on their chiller coils. But condensate has no dissolved minerals, so it cleans the coils rather than leaving scale.
There are many other tricks you can add when you decide that you care about quality, quiet, and efficient rather than first cost. There are lots of expensive AC window units out there, but they are all expensive for the wrong reasons (bluetooth AC? Really?). As far as I can tell, there are not any GOOD window units. I have a felling there is a big untapped market here (I know I want one!).

I so want to buy ones of these, but now I live in a place with no windows to put it in!
Good night
Bedtime now, so this will have to be enough ideas to get you started.
Good? Bad? Impossible? Already been done?
Please let me know in the comments below!
Also feel free to ask for more details if you are interested.