Recommend me a small complicated DIY Kit

I like building stuff and I've run out of ideas for stuff to build given my constraints.
I would love to build a kit car, but they're kind of impractical and upwards of $50k.

I was recently going to buy a speaker kit (www.madisoundspeakerstore.com/2-way-speaker-kits/lxmini-linkwitz-lab-speaker-kit-pair/) but they're too hard to drive for my available amps.

Requirements:
1.- Smaller than square 1m.
2.- Complicated.
3.- no requirement to machine wood or metal parts, I don't have the tools.
4.- < $2k

I've built:
dozens of drones (quads, hex and octos).
Helicopters.
RC trucks, cars, buggies, crawlers, drifters...
Class A and A/B Amps tubes and ss. Neil Pass JLH...
Robot... crap one bcos they're expensive.
Lego, LOZ... many; even built the new Chiron in 7hrs which was boring.
Nixie tube clocks... 6 of them.
Various tesla coils, measuring instruments (LCR, oscilloscopes), function generators, electronic nick nacks.
3D Printers.
100's of mods... pretty much everything electrical is now voice activated, I am greeted by Google TTS when entering the house.

For speakers try The loudspeaker kit
www.theloudspeakerkit.com/

I got alI my bits and pieces from them so I could set up tactile transducers on my gaming seat (car sim), then had to make up LF filters to cut out all the high pitch frequencies.

Set them up on your home theater chairs so you get all the bass running through the chairs not hard to set each chair up with stereo. Makes a hell of a difference.

Rebuild a Pinball machine
Doesn't tick any of your boxes though....
At first
Is an overwhelming heart palpitating mindfark,
That will turn into a multi disiplined obsession with plenty of like minded peers on the net for support.
Plus
There's a market for them when you're done

Restoring a pinball machine would be pretty cool, i was an electrical engineer in a past life and when I look under the bonnet of our pinball machine here at home it scares me.

Maybe look at restoring an old motorbike, they don't take up a lot of space and they are worth coin when you're done (never as much as you put in though, unless you choose very carefully) and you can simply ride it if you don't want to move it on .............. or put it on display in the living room if your wife lets you

Laughing Loon North Star Baidarka. No I didn't build it but I did buy the plans!

I was going to say an aviation project but it's out of his scope.
I had a mate buy a scondhand gyro and rebuild.
But even he says it's because his kids are adults and he's old so it doesn't matter if he dies
Also Im guessing fly has been there done that with aviation. His xray pics on here are not pretty.

OT but I say if you're going to spend that much money and time it may as well be on your retirement plan/ home
build your own world cruising catamaran rent the house and go cruising. Fusion cats have a kit that makes it easier (pre cast panels so you don't have to fair
www.fusioncats.com/kitcatamarans/fusion_the_smart_choice.php


A dude in Darwin I worked with spent years modifying a bus. had a large luggage door at the rear and when you made the area over it a queen bed base you could store a moke (literally) in there with ramps for getting around. very james bond. After years of work they set off, spent the first night at pine cr3eek just south of Darwin and are still there!

fly as an in depth project rather than just a drain on your pocket why not use your building skills and turn it into a side business. You never know it may end up being your ticket to an early retirement and enjoyable. For example if you built a big drone and used it in farm mapping or surveying. Or made them and sold them to farmers with training on how to fly. Or real estate photos or something. I know there's a lot of competition but because you already have a lot of the equipment and aren't paying retail to start maybe you have an advantage. Perhaps there's a gap in the market or something that is very expensive that you can do much cheaper.
Another guy I knew built his own very powerful water jet blaster. I cant remember if it was just a pressure cleaner or if it was also able to cut but it was on a trailer with a 4cyl turbo diesel. He made lots of money.
Anyhow what I am trying to say is that if you find some sort of niche that is in your area of enjoyment and you can grow and fund it ads another dimension. I started selling some stuff on gumtree and ebay (worldwide is a big market)
If you start doing well you have all of the business side of things to engage you as well and when it's money for jamit's a lot more fun than it sounds.

to make some money, anything to do with boats is worth considering.
Especially cashed up fisho's.

Seriously though, bird electrifying zapper device would have a market.
Self contained, maybe solar charge to a capacitor on a timer, piezo ignition?, to periodically discharge across whatever they are sitting on. Can only be a small voltage, but i'm not fussy, zap the b*arstards I say.

Lots of issues, regarding currents and electrolysis in a marine environment, but concept would work.
Well, they would get a zap, ** themselves on your boat again, then fly off, but at least the'd move on, hopefully.

Good for buildings, crops

You'd have a sale for anyone with a boat on a mooring, the damage they cause is a universal pain in the arse to any boat owner.

Fly, i'd even fund you to get it started. :)

Yes I have though about this for a while..

Perhaps use your skills and passion towards history and keep something alive .
It's been a personal hobby of mine for many years , to buy and restore old penny arcade machines and clockwork toys . The pre 1976 chip age. Older is usually quirkier and politically incorrect , like "shoot the jap " game . I once owned a early hand crank American toy that whipped a black man ( sic ) , but it's important history , I wish I kept it .
Before 1976 everything is mechanical switches and sequences . It's not easy but u could do it. The history and art involved is huge if that's a thing of interest . There is nothing prettier than a 1960 pinball machine . The tech involved is the same stuff that got man to the moon ! If you want smaller there are non electrical mechanical games that dispense a cigarette if you win . Very cool man cave stuff. Or how much electric shock can you take machines , even more cool. So wrong but soo right Don't get me started on antique medical electric shock therapy machines . Powered and crank . Also much fun at parties.

Another project I did in the past and need to revisit is building a ROV, there are a few kits available but I built mine from scratch.

With the stuff you have already done you would have most of the components in your shed, my next one, the first one exploded, will have a fiber optic umbilical cord.

adopt a child in a 3rd world country?