CAD and the Jeston Nano

Posted by: @robo-pi

Blender is BEAUTIFUL!

I've been up all night taking basic tutorials on how to run it

Cool, now you need a CNC machine to make all the parts you need. I've been able to fudge my way using a dremel in a drill press, but, that's amazingly time consuming. And taking out itty bitty bits of wood or metal is just so frustrating. I mean, I've done it, so it's definitely doable, but you need a real steady hand, and lots of patience

Posted by: @spyder

Cool, now you need a CNC machine to make all the parts you need.

No CNC machine, but I do have this:

It's manual, but pretty cool. ? 

Posted by: @spyder

And taking out itty bitty bits of wood or metal is just so frustrating. I mean, I've done it, so it's definitely doable, but you need a real steady hand, and lots of patience

The solution ,..... 

But a HUGE robot. ? 

Then you don't need to worry about all the micro stuff.

I'm currently preparing to solder a USB cable from an old keyboard onto a micro USB connector so I can use this cable to program some new Mega/ESP boards I just got.   Trying to hold everything in place  is a  nightmare.   I'm going to attempt this with a soldering iron, but I might be better off  using SMD soldering methods with solder paste and the hot air soldering station.   I've already done some SMD soldering and found it to be surprisingly easier than I thought it would be.

In the meantime getting back to Blender.   Today I followed an 11 minute tutorial to make a car tire.  It took me about 11 hours to complete the tutorial. ?  But to be fair, I was keeping meticulous notes and taking my time to  execute every little step.   Even so, some of the things I was told to do I didn't  understand why they were necessary, so being shown how to do it and understanding how it works are two entirely different things.

In any case I'm ready to move on to starting over again from scratch to draw up my own tires.  I already have these tires.  I'm just doing this to learn Blender, plus I'd like to have a drawing of my actual robot.

Here's some photos of the actual base:

And here's the tire I just drew up in Blender.  An 11 hour tire. ?  But hey, I'm learning Blender.

By the way, the Jetson Nano performed at warp speed with this 3D drawing.  No hesitation, or any problems of any kind.  This little bugger does really good.  I have two of them already and I'm even thinking about buying a third one!   These little suckers are addictive. ? 

Especially when they work this well.  

I was afraid that 3D drafting might be out of the question, but Blender runs just fine on this thing.  At least, so far.

@spyder,  I have a question about a possible switchable SD card hub?

Let me start with a photo of a recent USB hub I just bought

This USB hub has push button switches so you can turn USB devices on or off instead of having to constantly unplug them when you want to remove them.   This come in quite handy when you're programming several different microcontrollers and only want to have one of them available at a time.  So having  USB ports that can be easily switched on or off is pretty nice.

I've been looking for a similar thing  for micro SD cards, or any size  SD cards really since I could use adapters if necessary.

How would I use these? And why would I want one?

Well, with the Jetson Nano the SD card is the main Boot Device.  I'm currently using 3 different SD system cards.   Of course I can only have one plugged in at at time.   So I'm constantly having to unplug one system and plugging in another to change over to a different boot system.

If I had  a  switchable hub like the USB hub above I could plug in  4 different SD system Cards and then just choose the one I want to boot from.  I would only be able to have one  SD card selected at any given time, but that's ok   It would still be nicer than having to  unplug and plug a new SD card into the nano.  Then you also need to have place to store the  SD cards that aren't  currently in use.

If I had a switchable SD card hub I could leave four different boot systems in the hub, and just choose the one I want to boot from during any given session.

This might seem  trivial but it would really be nice to have. 

So far I haven't been able to find anything like a switchable SD card hub.  I could probably build my own, but that would be a heck of a project too.  If I do end up building my own switchable SD card hub I wonder if I could use those  SD card readers that are designed for  use with Arduino.  I have  a couple dozen of those laying around.

Any suggestions?

Maybe.

I see 2 issues here... 1st being convincing the nano to boot from USB, and 2nd, some kind of smallish sd to usb device. Preferably 3.0 obviously

We could speed up the process by sticking to strictly USB, and skipping the sd part tho. This would only leave the problem of convincing the nano that it wants to boot from USB, which could be problematic, but not insurmountable I'm sure

I know that the pi can be booted from USB, so there must be a way to get the nano to do it

Ah, here...

https://www-jetsonhacks-com.cdn.ampproject.org/v/s/www.jetsonhacks.com/2019/09/17/jetson-nano-run-from-usb-drive/amp/?amp_js_v=a2&amp_gsa=1&usqp=mq331AQCKAE%3D#aoh=15758418510569&csi=1&referrer=https%3A%2F%2Fwww.google.com&amp_tf=From%20%251%24s&ampshare=https%3A%2F%2Fwww.jetsonhacks.com%2F2019%2F09%2F17%2Fjetson-nano-run-from-usb-drive%2F

That doesnt look right. I'll try it again when i get home

@robo-pi

Ok. That link works. I've never actually tried it tho, either on the Pi or the Nano, but the description seems about right

I know that there's also another way to do it on the Pi that makes a permanent change to the firmware,  (I think Explaining Computers did that video. I can't remember) but even if such an option were available for the Nano, I suspect that you wouldn't want to make such a permanent change. I know that I wouldn't

@robo-pi

This is the video I saw for the Pi. I thought I saw it recently, but, I guess it was longer ago than I thought

Posted by: @spyder

I see 2 issues here... 1st being convincing the nano to boot from USB, and 2nd, some kind of smallish sd to usb device. Preferably 3.0 obviously

My fault for not explaining correctly.

I don't want to run the SD card hub from a USB port.

What I want to do is plug the SD card hub directly into the SD socket on the back of the Nano.  And then be able to choose on the hub which SD card is connected.   So there won't be any USB ports involved at all.

I showed a picture of a  USB hub just to show that some of them have switches where you can select which  USB  device is connected. I basically want the same thing for an SD card slot.

So this hub would plug directly in to the SD card slot on the back of the Jetson Nano, but then offer four ports for selecting from four different SD cards.   Of course,  you could only  have one  SD card selected at any given time, but that's okay. 

As it is right now I have to keep unplugging SD cards from the back of the Nano and plugging in the one I want to use.  It's a bit of a pain.  

I'm currently using three different SD cards.

1. One dedicated to Paul McWhorter's AI lessons.
2. One dedicated to Blender, or CAD, and hopefully KiCAD too.
3. One dedicated to Kdenlive and Video editing and production.

I can easily foresee the potential for even a forth dedicated SD card (especially if I ever do anything with ROS).

So it would be nice to have a way to just select which SD card I want to boot up from instead of  having to unplug them and plug the other one in.   Then I also need to have a place to store the ones I'm not using so I don't lose them, etc.   If I had them all in a hub where I could just select the one I want to boot from that would be  fantastic.  

But,  no I wasn't thinking of  using a USB port.  I just referenced the switchable USB hub as an example of  a switchable hub.

I might need to build my own because there probably aren't too many people out there who would want something like this.   Then again, I might be onto a new product?   This could come in handy for Raspberry Pi  users too who want to be able to boot from different SD card OS systems.  Just plug the SD hub into the SD slot and then plug the different OS SD card systems into the hub, and choose the one you want to boot from when you boot up.

Seems to me like something other people might be interested in as well. 

One hub to rule them all! ?  The Lord of the Hubs. ? 

@robo-pi

Ah, ok. Well, hang on. I've got something in my lab that I haven't used yet which might give you some ideas...

Looks like I might need to build this myself.

Here's a plan:

First I get a micro SD card extension cable (about $7)

This will give me a way to plug into the SD card slot in the back of the Nano (or the front of a Pi). Then I can just cut the other end of the cable off and mount it to a PC board.

Then I'll need some SD card holders for the PC board:

Then I'll need some two position push button switches that have enough contacts.  Not sure how many contacts I'll need, or where I can get the correct type of switches.

Then I can create a nice PC board to build the hub on, draw it up in KiCAD and have PCBway make them for me.

After all that, I'll have an actual product. ? 

Since I might be the only one on the planet to offer these I might be able to sell quite a few of them before they catch on.

All that's needed is a way to switch which SD card is connected to the cable.   It shouldn't require any electronics other than the actual switches.   It would  be nice to have it so that only one SD card can ever be connected at t time since it wouldn't work if more than one SD card was connected.  So the switches would be nice if they acted like radio buttons that only allow you to chose one at time forcing the others to pop up.

Finding the correct switch for the project looks like the biggest hurdle at this point.

@robo-pi

Ok, this little duhickey is an adapter thingy to go from microSD to SD, so, if you want this particular item, yer gonna have to use the adapters that come with most micro SD cards

The beauty of it is the extension cable, so you don't have to futz with the SOC every time you wanna change SD cards. I know that on mine, I can't swap out the SD card without first unscrewing the SOC, and tipping it up. If you were to use this, you could just keep the socket within arm's reach. 

The cable on this one is 18 inches long. That should give you enough room to put it someplace handy

@robo-pi

OKay. Here's a thing. I bought it cuz... well, who knows why I buy such random stuff

Probably just a tad bit unwieldy, eh ?

It is true that just by using an extension cable alone that would be an improvement.  Then I wouldn't need to keep digging into the back of the nano.  But then you still need to swap the cards and have a place to store them when they aren't in use.

The biggest hurdle to the hub project appears to be in finding suitable switches.   I could just use a four-position rotary switch and have that physical switch change which switching IC's are active.  But then I'd need to also buy more IC's to do all the actual switching.   Might not be too bad.   IC's are cheap, especially SMD.  And I don't think it would increase the cost of the PC boards either.   So that might be the way to go.  Just  use a simple four position switch and  have it switch  IC's the do the actual line switching.   I wonder if I could do that without having to add any extra wires for power?  I'd like to keep it to where it only needs to plug into the original SD card slot and not require anything additional.

I just counted. There's 8 contacts on that cable

Posted by: @spyder

@robo-pi

OKay. Here's a thing. I bought it cuz... well, who knows why I buy such random stuff

Probably just a tad bit unwieldy, eh ?

That's pretty nice.   You could probably use that to turn house lights on and off.  And even small motors.  Like a fan, etc.  In fact, I'm using a relay about that size to run a large house fan.  This is actually blowing hot air out of a heat exchanger.  It's been running for several winters now without any problems.