The Pi4 already started making power delivery to the board more complex by allowing USB-C Power delivery, USB-OTG, and eventually figured out how to properly handle a USB-C data connection also.
The iRobot Create3 robot offers both 3A 5V USB-C power delivery to a USB-C connected Pi-4 and USB-C “networking” with the robot over the same cable.
The new 3000mAh Li-Ion juiced GoPiGo3 with a Raspberry Pi3B+ still wins the “best playtime award” in my book with 4-6 hours of mixed driving/thinking use.
The Turtlebot3 Burger only comes with 1800mAh Li-Ion (and Pi4) for a spec’d “2h 30 min Operating”
The “Official Pi4 Power Supply” delivers 5.1V at 3.0A to the USB-C connector. It will be interesting to see if the upcoming 2GHz Pi4 will be offered with the same power supply or a slightly beefed-up official supply. (The existing C version 1.75GHz Pi4’s draw an extra 100mA when overclocked to 2GHz.)
I am pretty sure the existing GoPiGo3 - Raspberry Pi3B+ is meeting all of the grade-school education market needs (with the exception of a sexy case maybe). The more that high schools try to include some introduction to autonomous driving technology, the GoPiGo3 will show its aged design in power supply, processor choice, and software support.
Sad but “the writing is on the wall” for anyone and any robot to read!
You have to admit that our use-cases for the GoPiGo3 are not exactly “mainstream” - and the folks at MR have really dug in their heels about wanting to focus on the “education” market.
Again, I can’t read minds, and I really don’t know how deep their market share is, so I’m not really qualified to “armchair quarterback” their marketing decisions.
As I see it, it kinda’ goes like this:
If you’re trying to teach robotics in a secondary school environment - a GPG3 and a Pi-3(+) could be your ticket to success.
If you’re trying for a thesis presentation like the last couple of people were, you’re on pretty solid ground.
If you’re trying for a Nobel Prize, string theory, or a whacked-out PhD presentation, you might be stretching it.
DARPA challenge? BattleBots? Fuggeddaboutit!
But then again, it depends on yourself, your ingenuity, and what you’re trying to do.
IMHO robotics, as a hobby, may be limited by definition.
There’s still a lot of room to grow as far as the maker-space is concerned and I don’t see things getting back to the way things were in the 50’s and 60’s as far as making things are concerned. A lot of that was fueled by a saturated “war surplus” market of cheap but sophisticated equipment from the second world war and Korea in the same way the PC boom in the 90’s was fueled by the fallout of the dot-com bust.
That really is the right thing to do - separate supply path to the processor and to the GoPiGo3.
On my prior bot, I used a 7$ Pololu 10A Pushbutton electronic switch, (that had an open enable), between the battery and the bot supplies. I never did wire up the enable for processor shutdown of all the supplies though - needed a double-E to design an RC shutoff the processor could start in motion on the way to shutting down that would jerk the power off after the processor shutdown.
There is one other option that we haven’t discussed:
I remember my father teaching me about electronics and such-like when I was a kid, but we were from two different generations and the technology he grew up with, and learned from the Navy during the second world war, was rapidly becoming obsolete. By the time I finished high-school, I had pretty much exhausted what he could teach me. (At least with regard to electronics and such - he was a clever old guy and could do things nobody ever imagined!)
Now we are the “old geezers” and modern technology might well be passing us by too.
Today we have high school and undergraduate college students doing things with lane finding and obstacle avoidance on a Raspberry Pi that would have gotten them classified top-stinkin’-secret a decade or so ago.
Another few years? Who knows!
When my granddaughters get out of school and college, they’ll probably be looking at career paths that don’t even exist today.