What’s the coolest ‘just for the joy of engineering’ project you’ve ever made, and how did you pull it off? We are asking e14 in our Join, Share & Win Competition

robogary I don't know about "The Joy of Engineering"... but you get my vote for "inspiring".   Thank you.

You never know when that KNACK moment will happen. I provide opportunities,  fuel , and conditions then one day, like a campfire it will ignite. 

I love the question.
No specific project has seemed worthy of mention, but the thought "Because I can" keeps coming to mind.
Why build it?  Because I can.
Or maybe it's because it works.
Why build a crystal radio when I'm over 60 years old? ...because it works.  Still.
  I wish one of my grandkids would be as amazed about this as I was.  Of course... it took me decades to come back to it. 

 robogary Thanks for sharing this story.  I was going to do something similar and came to the conclusion that I wanted the grandkids to actually learn from the experience.  In what life did I ever expect to be telling a 5 year old "Keep you foot on the gas!"?  NONE!  And yet... this week.  Last week.  I just KNOW that I will live to regret saying that. 

I really like the 50% reverse though. 

Great story ralphjy 

robogary said:

This is what it looks like this now. The 20 month old driver is not so great with the steering. 

She is cute though.   

And things look more organized under the hood.

robogary said:

The 20 month old driver is not so great with the steering.

And then they grow up...

This is what it looks like this now. The 20 month old driver is not so great with the steering. 

2 LEDs on the hood show if the fwd direction is locked out or if the fwd direction is speed limited. 

The LED floodlight are removed because they got too hot. 

3 Arduinos under the hood , one translates the throttle radio PWM to 0-100% PWM to gate the H bridge. One Arduino is just for ping sensors, the status LEDs, and discrete signals to the throttle control. One Arduino controls the OLED matrix eyes. 

I have done lots of cool joy of engineering projects, but the early ones that got me started were possibly the most fun.  I used to spend a lot of time in the library as a teen reading the latest copies of Scientific American and Radio Electronics.  My older brother was getting into photography and need a slave trigger for a "fill" flash unit.  I happened to have just read about a simple circuit and I built him one and housed it in a Sucrets tin.  I still keep that project as a reminder of how I got started and as an example how awful I was at soldering and construction in general.  Here's a few pics.  I should have left the original paint on it, but my brother didn't want that so the tin is now pretty rusted.

The circuit worked great and my brother got a lot of use out of it which gave me quite a sense of accomplishment.  It got me into building more complex circuits which were mainly kits because back then it wasn't easy to source parts or build housings (no 3D printer  ).  I remember building a capacitive discharge ignition unit when I first started driving, but that went with the car when it was sold... 

It looks like I scavenged this project at some point because the SCR is missing and the tripod mount was inside of the tin instead of on the bottom.

dougw said:

I expect to play with it for many hours

The rest of the Rube Goldberg Machine perhaps ?