This video:

Chat:
Al:

Index:
00:00 Terry: Is again having trouble drilling his stainless steel panel.
02:05 Terry: Wiring plans.
03:15 More about drilling stainless steel and tempered steel.
06:00 Al: Talks about his embedded code. ROS Serial.
10:20 Jeff: A quick way to show path coverage in RVIZ.
22:10 Jeff: Talks about cross track error.
29:00 Jeff: Talks about choosing a processor board (yet again). Wiring methods.
35:55 Jeff: Comments about using a Blue Pill board as an Arduino.
36:50 Using uart communication between low level boards.
43:25 Discussion about remote control.

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Lawn Tractor Automation YouTube page:

Index for Lawn Tractor Automation group:
http://sampson-jeff.com/RosAgriculture/LawnTractorMeetingNotes.txt

Index for the original ROS Agriculture group (~250 videos):
http://sampson-jeff.com/RosAgriculture/readme.txt
http://sampson-jeff.com/RosAgriculture/ros-agriculture-youtube20230104.txt

Okay well last week I said I was going To be uh Mounting my uh Milwaukee Um Battery holders onto My robot And but I had to drill through some uh Stainless steel sheeting Well after spending a half hour on one Nine 64 inch hole with a brand new bit And still not being through it I finally decided I'm giving up on Trying to go through the uh stainless Steel sheeting And we'll mount it on the side So if I can change cameras Okay let's see I'm gonna have to turn off Background Okay now I think I can get it Camera is long enough I had this Hole right there And that was after a half an hour of Drilling Total in about 10 different times So I've decided instead I'm going to Mount it on the side here I'll only be Using two of those three holes Which I don't think should be too big a Problem But it gives me then the opportunity to Still be able to get out the battery Very easily and still have it connected

To all of the Power connections I need In there So now I'll switch back to my other Camera And um I did not uh Get a lot done otherwise This being tax season so I still want to Get those two mounted and wired up So that I have uh fused power for Motors And so forth Then I plan on getting the uh Itsy bitsy wired up with or the motor Controller and the uh voltage monitoring And then the rs-232 communication to Raspberry Pi which will eventually get Put on here I still need to get uh Ross loaded onto both the Raspberry Pi And onto my laptop so I can get those Two Talking to each other And that sounds pretty ambitious for This coming week That's it The holes that were in your stainless Steel how did they originally get in There Um that was back probably about six Years ago when I before I had the Piece mounted and I was able to use my Dad's drill press And had and had him helping and He was used to working with the

Stainless steel sheet so he knew all the Tricks And had the right tools I had no idea it was so hard And another option b just get a sheet of Aluminum and remake that plate and I Don't know how many holes and stuff he Got in it but If it's going to be that much much of a Problem we might be better off with you Know putting something else on there This is kind of the the test bed anyway So That might not be a bad idea I found out one time if you've pulled Bed frames out of the trash to use this Angle iron that those I I I went through The same process I was trying to drill a Half inch hole through one and I burn up Like four or five drill bits and I found In the back of the back of the building I found a drill bit sharpener so I kept Resharpening them and finally got to Drill through and then somebody said oh Well bed frames are hardened they're not Just standard mild steel so you know They look they look just like the stuff You buy at the hardware store except They've hardened the things so it turns Out I could drill like a quarter inch or Up to 3 8 inch hole seems to work really Well but I got up to half an inch it Just would not it would not cut anymore And I don't know why

Such as more things that you learn over Time Well I I did some some research and they Said that uh stainless steel is not Hardened but it hardens very quickly if It's heated And so people who Use the old okay if it cuts okay at a Slow speed it'll cut even better at a Fast speed that's just more heat and Causes the material to harden even more So I've been going at very low speeds But it doesn't seem to be cutting And I've tried multiple bits But I don't have my dad's uh Tools or skills for sharpening bits Properly for stainless Steels so That's that Next Step you want to go where you want me to Go Uh you can go Uh let's see progress on my side Um As a reminder I've got this Radio control you know hand-built radio Controls unit and it has a mode Switch on it to Signify whether or not I want manual Control or whether I want What I'll just refer to as command Velocity control and so Um In my embedded code I've got

This tractor control that's the code That runs on the Microcontroller that sits on the Tractor and I've changed that a bit to You know Based on the value that the switches Providing to change them the mode so That's all relatively easy and simple But then it came time to subscribe to Command velocity and [Music] Um You know have that have the Microcontroller actually talking to them To Ross and that's I mean you could do it a couple of Different ways probably I could like Write an mq mqtt Server or use raw serial which is the The Ross way and I was trying to make The Ross Way work and I've never had so Much trouble Um Getting raw cereal to work so I've got Uh You know I've been spending time on These other programs just focused in on All I want to do is something simple and Um Getting that include statement Recognized I don't know I must have Messed up my libraries or something Um But I finally got you know a very simple

Program to work so now I've got a Translate that into back into my um Into my main program Um And this is where I had mentioned while We were off the Off the um Off the recording there's this there's a Function called Supposedly create timer in Ross and um It would just make it the code a little Bit cleaner and I'm just going down a rabbit hole trying To make this work because In this particular program Um yeah it just doesn't want to find That Library and it's throwing all sorts of Errors about Hey the timer isn't a part of the Ross Package So anyway I might spend a little bit More time on that timer I might rebuild A test laptop To try to figure out what I've done with My libraries or I might just go back to What I consider to be the um Old this standard way the way that I've Always known to control the um The loop which is You know just this sort of thing Um This is in my main Loop So

That's where I'm at fighting with the Ross cereal and my libraries and Timers and trying to get my um Uh tractor to subscribe to command Velocity so I could take a Steering and angle Steering and and throttle Command And everything I've done is out here on The embedded code That's it So I said I had several things to talk About today uh first we'll start with The thing uh a meeting or two ago we Were talking about displaying things on Arviz and Terry said well how how can I Display the width the path coverage of The snow blower and I said I didn't know Right offhand so I went back and played With that a little bit And it turns out uh let's see some way It's a way Picture of the screen screen one So it turns out if you come in here Let me let me let me try something here Let me let me move this over to my other Screen And stop sharing this screen and Share screen two And yeah that's exactly what I want to Have happen Back over here where it belongs This one over here I think I might get a Better display if I if I do this

So this is um basically the these red Things getting left behind are one meter Wide and a tenth of a meter thick and What these are these are actually the Arrows from from odometry so if I'd go Back Yeah that's that's going to be real Convenient let's say close that That was under This one So if we look here and of course it's Going to show us threads because that's What that's what they want to do now if You zoom in on these look at them these Are just the little arrows on odometry You turn on odometry and it puts down at The rate that you tell it it puts down An arrow to tell you where the the base Of the thing is is where odometry is and The angle is telling you what the Heading is so that's just a standard Thing built into arviz you can you can Control that and let's see is that show Up over here And I don't have the parameter shown it Just says Odom is turned on so as you Drive around it leaves these arrows Behind So then I went in and played with Played with the values on here and over Here on the the left you can see that Under the uh The shape of the arrows so so it's Putting down arrows and then under shape

Of the arrow uh I set the First of all I set the head and the shot Or the head length of the head radius so When you look at the arrow it draws us Like a cone on the end of it as the head So you can control how how long it is so You can have long pointy arrows in fact Here's here's a reference here's a Reference Arrow over here you can see It's kind of a long pointy Arrow or you Can make those short and fat if you want And you can make you change the diameter Of those so I came in and I just said I Started off trying to make those wider And they don't work because then the Lighting since there's a cone the Lighting makes them in the shadow of the Entire time so what I did was I came Over to the shaft or the head length and The head radius I sent those down set Both of those down to .01 meters which Means I'm basically setting down to a Point where almost non-existent if you Zoom in enough on on one of these things You might be able to see a little thing Sticking out there but basically that Was to get rid of the the head of the Arrow and then they have the shaft Length and the shaft radius and on this One The shaft radius is set to one meter and That's what's controlling the width of This let's see kind of zoom in again So setting the width of this thing is

The one meter over here on the the left Where I said the shaft radius is one Meter because technically if you rotate This around those are actually big discs They're not it's not just a big wide bar Like it looks like so if I turn it aside Those would be real nasty looking big Big round discs but you know since this Is a fairly quick and convenient way to Do it that's just a I thought this was a Reasonable way to go and then the shaft Length the 0.1 controls how thick how Thick each one of those slices will be So just by playing with those numbers You can make it do all kinds of uh Interesting things and as you drive Around let's see how we get back Oh I thought it had a word show it going Up around the corner there I guess I Guess I don't this is all I have right Here but as you drive along it plops These down as you drive forward and what Controls that is you look back over here And it says You have position tolerance and angle Tolerance so the position tolerance says If I've driven a tenth of a meter it's Going to plop one of these down on the Screen so I can make that I could spread That out to say one meter if I want a Lot fewer ones on here or I can set it Even closer if I want that so things you Might want to do is set you know change The thickness from point one to point

Two so it's a bigger wider thing and Then set the spacing like one one meter Apart so it gives you like one right Here and the one right here so that's Just a matter of playing around and the Other thing associated with that is the The keep so this is going to keep 200 of Those things on the screen at any time And you can run that number up and down I don't know what the maximum is before It starts bogging things down but Um But that's that's how that works well The other thing is I said yeah position Tolerance was after it's moved a tenth Of a meter it puts a bar on the screen And then you have the angle tolerance And I set it to one just because I Didn't really care that says as the Vehicle is turning say turn into left or Turning to right this is a if it's Turned this angle then it will Automatically put one of those uh but One of those markers on the screen So all in all that that is a quick way Say if your snowblower happened to be a Meter wide you can set this to a meter Wide and the only other problem right Now is that this is actually putting out On Odom which is the uh the the center Of rotation of the vehicle because That's what odometry gives you and on Terry's case you can have a snow blower Out front here so it seems like the

Quickest way to solve that is Just write a note that says subscribe to Odom And then then add the distance from your Basically add the wheelbase so you take The distance from your your back wheels Out to your snowblower add that onto it And republish that and call it something Like uh snowblower Odom so over here on The left you can see under o Dom is Subscribing to the topic Odom which is Coming right out of the uh in this case It's coming out of uh gazebo to tell you Where you are and you can just create Another one of these and call it say Snowblower Odom as the the the display Device and then the topic again call it Snow snowblower Odom or whatever you you Created with that intermediate node and I think that would give you the fact That as you drive around it would be put In the putting the marks out front here Where your snow blower would actually be Located And whether it's a four-wheel you know Ackerman or four-wheel skid steer or Two-wheel differential you know it all Works the same way you've got the the Odom's telling you where your rotational Center is and I guess on Uh let's see is that gonna Actually I'm not sure if you go to a Four-wheel Uh differential Drive I.E skid steer I

Don't know if Odom is going to be placed Here or placed in the center of your Vehicle maybe that's just a matter of as You create it you tell it where you want Odom to be but then you know the the Odon message coming in from gazebo is Going to say this is where you are so That that might take a little plane Around one way or the other to get that To uh get that to come out So so Let's see did I have If I back up to the other one I was Talking about it how how many it keeps On the screen let me go back to this one And see what I had there And this isn't uh real obvious here Because I I stopped it fairly soon here With this so I started at zero zero here And as I was driving up then every I Probably had this too set to a tenth of A meter or two tenths of a meter so as I Drive along it keeps putting these Arrows on it comes around here and see It keeps that many of them and I I think On mine I increased that out to either Like 500 arrows or something but as it Drives around when the thing is is Coming up here on the left it's coming Back down like this It gets to be right about here and then The arrows over here start disappearing Behind you so so it does two things one It shows you most of the arrows that are

On there with the numbers I have right Now And then number two it's automatically Deleting them so by the time you drive Back around to here and come to a stop Right here it's deleted up to about up To about here so you got an open path so You can you can see as it's driving Where it's putting the things so that's Just a few more a few more things I Noticed on that so it's it's something You can play with you don't have to you Don't have to write a bunch of extra Code to make this work you can just go Put those in and say do it and it it Does in fact work Okay thank you yeah is there any more Any more comments on that I say it's kind of it's kind of a hack So but it does show you you know if you Want to see the coverage you're you're Doing you you can you can indeed see That But I think you're going to find out When you go to drive this thing that You're probably going to want to have Overlap between the pieces anyway right You know from from my experience with Snow blowers or a shovel it turns out That you know no matter where you push The snow you are going to have some that Pushes off to the side so you're Probably gonna end up you know Overlapping uh your your paths Anyway by

The time you're done And you'd also mention that when you Back up you wanted to either raise your Your blade or or raise the snow blower Or turn it off but I think again you Know for my experience with snowboards It doesn't really matter you know if you Back up whether the the blade is down or Up it's I don't think it's going to Matter so but that's just more than when You when you get something running you Can actually go out and play with the Snow then you'll it'll become obvious Real quick if you need to do things like That or not I I was thinking of it more From the the Energy saving If I'm going backwards 50 of the time do I need to have the the blower running Yeah okay And you're right it does depend on you Know how long how long does your battery Last and what you can make it do so that That that that's a very valid point There Okay so the next thing I want to talk About Let's see I'm gonna have to go back here To find that Uh when we were talking about keeping Track of where you've been and and Staying on path Uh I Let's you have to do this now

This is part of that path that was the Serpentine path it just simply rotated 90 degrees here from what we just saw But basically for the test I basically Started at zero here on the left so it's A zero zero and it drives down here to 10 comma zero so it just creates a Straight line there and this this big Loop outer is actually made of three Individual arcs there's one Arc right Here to go from here it actually should Bend out like this and then there's an Arc that goes from here all the way Around to here that's a four meter Diameter Arc and then again there's a Little Arc here to connect those back Together And then from there it just again draws A straight line back to this point where It starts into another small Arc and Then if I go into uh that code that that Juan and Matt were playing with they put In a I probably don't have a convenient way To pull that code up but but base buried In that code there was a a comment that Said uh calculate the off path error and Everybody just assumed that what meant How far is the base link of your vehicle Off the path that we're trying to follow So so again here's our path we're trying To follow for the vehicle is sitting Here like this and base link is in the Back and the front of the vehicle is

Here and then your look ahead is out Here somewhere I think it was something About I was trying to calculate how far The look ahead point is off the the line That's drawn by your vehicle so I don't Think it's actually telling you how Close your vehicle is to the line it's Just trying to it's an internal Calculation saying our look ahead is out Here because when you get down here and Start going around the circle you know Your vehicle can be right here but the Look ahead is out here and that that's Definitely you know showing you a big Error there So I think what you need to do is go Through the code and find the point that Says measure base link to the line and Publish that so if I back up here to This one this this is what you give you Plot that out so this my vehicle wasn't Pointed straight on the line because I Had come around and when it stops I Stopped putting in the right direction So when I first started up it's got this This weird thing here and then this this Right here is the straight line going to The right on that picture that I just Had so so it's trying to align itself it Has a little bit of overshoot and then Once it's on a straight line it's doing A pretty good job of of tracking it and Likewise when we come back out of the Big loop here against the straight line

Is doing a good job So if we're on here we're on the Straight line going to the right we go In that little Arc here's here's the Indication from the little Arc that we Change direction so it jumps up here and This this is the the big four meter Diameter Arc that's uh showing us here And when it changes Direction it goes Back into little Arc and it shows this And corrects and it goes back to drawing A straight line again but as I got to Looking at this you know number one I Couldn't figure out why does it have all These uh spikes out here and that's what Led me to believe that this is not shown As base link it's something about the uh The off or what they call the the The look ahead pointer and I think each Time each each one of these spikes is That that segment that I just showed Again here we'll go back here And this is the this is the one that has A one meter segment so this picture Doesn't actually match what I just Showed you so when I ran it I I Increased it so instead of having one Meter between these segments so you can See a point there a point there a point There one there one there so you see It's kind of choppy as it goes around so I'm guessing that if you would run it Against this you're going to get uh one Two three four five six you're gonna get

About 10 or 12. I think you're getting about 10 or 12 of These things and I had increased mine to The point where I'm saying every 0.2 Meters and that number one it Smooths Out the curve a lot and if you just do Some quick calculations I decided There's probably 30 to 40 segments Around that big loop and by looking at This I didn't count these but that might Be 30 to 40 showing up there so I think Uh number one I think we're just simply Looking at the wrong stuff here and then Secondly this indicates that I think This is you know anytime it switches Segments this is bouncing back and forth If also if you look at this one right Here you can see it comes up you can see There's a a background sine wave here as It's trying to track going around the Circle and it could be by tuning values You can get to get rid of that but these Little spikes shouldn't be on there at All if we were looking at the right Thing Because the vehicle can't move back and Forth that fast so it's that's why I Think it's something to do with the uh That look ahead pointer and you know That's way out in front of the vehicle As it's moving back and forth So the point is uh I had found this and Back on uh here let's uh Do I need to say anything more about

This this is this is putting out what Was called off path error so I come back Here to This one And okay what did that do it look so of Course it opened that another tab just To make me just make me mad here Let's let's don't find it there let's go Back to random And this one Okay that comes up so something else Matt had done he he found this cute Little uh text display that it's a Plug-in for our viz so you can plop it On the screen and then subscribe to Whatever topic you want so you can put Out numbers and they show up on the Screen here And his his point was as he drives Around here it would uh the pure Pursuit Would calculate what it thinks is the Off path error it would publish that By I can't remember what the name was Then he had a little python node that Would subscribe to that and just Republish it so it basically shows up on The screen here so if I'd gone down Further down this path I could figure Out how to get that plug-in to work and Then uh you know get the things tied Together so I could actually watch these Numbers change that I'm driving around And even watching this if you go pull up His video on this you'll see that uh

Part of the time it'll it'll be up like This and it's got the same spikes there And when it turns goes the other Direction it's got the same spikes going Down so it's basically text on top of a Little oscilloscope display here Okay nice can we do this So you can see in the background there's A few little bumps right there and then Right here you can see see big spikes Coming out as it's going into the end of The curve there so the the point was yes It would be very handy to have and you Know I was saying before it it couldn't Be right because I was nowhere off by a Quarter of a meter so down here this Grid is one meter and up here you can See his was off by by like a meter or so And I I can't I can't set my parameters Make mine act as as bad as his did so I Think they might have been something Funny between the the stage and the way Things were scaled is why it was off so Far And again I think this is showing it's Not showing where the vehicle actually Is I think it's showing that yeah I Think it's showing you he's a look ahead Marker or Um actually no actually it's not so Anyway I I think if somebody plays with That we could figure out you know better Ways to to make that work And um so I could think that's all I had

To say about that Any any questions on before the next Thing Very interesting Okay so let me do [Music] Stop sharing Okay and then the other thing was I you Know I'm I'm again back to the point I'm Trying to decide how do I want to uh Set up my This might screw up the the my Background might screw this up but Anyway this is the this is the board That was on my uh Sammy 2 robot that was Just a St micro eval board it's got a Fairly big processor it's got a lot of Eye opens so it's got there's dual rows Of pins here so it's got like 100 pins On this on this board so I could I can Do quite a bit of stuff with that and Then it turns out uh when when Juan Found out you can't buy that board Anymore he looked on either Amazon or Ebay and came up with this board And here it has a size comparison See it's the it's basically the same Chip on the little board but it doesn't Have as much junk on it so it doesn't Have the the big board has some kind of Fancy audio processor and some other It's got lots of LEDs and push buttons On it and the little board is basically The so it's got the chip here and then

It does have an SD flash card socket Here and then it does have there's some Kind of a like a Serial flash memory or Just some external things stuck on there But other than that it doesn't have a Lot of extra stuff on this board to get In the way it still has dual row dual Row header here and down here and has Probably almost It might have the same number of pins or Just a few less pins on the thing and it This one was originally I think twenty Dollars Twenty dollars but you can't buy it Anymore and this one I think came out or I don't think it was like eleven dollars To Fifteen dollars or something but it's Got the same the same processor you can Buy it with the same processor or Processor with half the memory for you Know five dollars cheaper or something So that was something that Juan was Playing with and I did get that to work And then the other thing is the Blue pill board Which is uh just a smaller so again Comparing the size on these see it's a Much smaller board and it's a the Processor has much fewer pins on it but Theoretically if you play hard enough You can load a Arduino boot loader on This and get it to work you know so I Can fire up the Arduino Arduino IDE Write my code and say download or I

Think they call it upload and it should Load the code and start running so if I Could get that to work that might be Beneficial just so you know all the Different development systems are the Same they're all using the same Arduino IDE and all all three of these chips They're all St microchips this is Actually like a cortex Um uh F F1 or M1 it's an older processor But it still seems to have all the Peripherals that that I would want on The thing and it's still quite fast and Has enough RAM and ROM to do the job so I might switch over to something like This and as opposed to and the main Reason I want to go with the SD micro Parts is because I can do up to four Channels of quadrature decode because It's got Hardware built in to do that That's my main reason to stick with These and possible part of it because That board was used on my Sammy too so I've got code written that knows how to Talk to those peripherals and it'd just Be a matter of hacking all the stuff Together Another issue I had was you know again So this this board this happens with the Blue pill board's got uh pins soldered In the bottom so I was trying to decide Do I want to stick that into a Proto Board and just plug in wires or do I Want to get a piece of perf board and

Solder down some sockets I had a perfect Board laying in the way here but anyway Anyway just solder some sockets down on A perf board and put connectors do I Want to do it that way or another option Would be to use these uh To really really get a quick hack you Know you got these these jumpers that Are the they call them the DuPont Jumpers and it's just got you know um You've got the little connector on the End you can plug them onto the pins well I could just take them and and plug Those right on to Just plug it just just to experiment Just plug them right onto these pins and Then just plug them into whatever I want At the other end I wouldn't do that you Know in real life I don't because they Did have a board flopping around all Those wires there and they're they're Going to fall off on you so you don't Want to do that And uh I don't have the A good example because I took this big Board and took a took a big piece of uh A big piece of perf board and then Soldered down you know uh connectors for Those two and just plug this onto the Perf board and then I had uh extra room I just put connectors and stuff and just Wired point to point to make all that Stuff work so it's back to the point I'm Just trying to decide you know how how

Would I want to do this and you know What's what's the quickest way and But I know the quickest way is not going To be the most uh The most secure in the long run so That's yeah just just more stuff to Think about there And I think it comes up there I keep Thinking well how could this be more Universal well you could put you know a Solder your or plug your plug your board Into a piece of perf board and then have Standardized connectors which means now All your peripherals you want to or your External devices you want to hook up you Know you have to make those fit that Type of connectors so you might have Like four pin connectors that would have Say plus five ground and two signal Leads on and depending what you're Hooking up to so the quadrature those Pins would have to go so so far your Connectors could go to quadrature decode Pins which could also be used as timers That can also be used as standard i o or Whatever so that that might be another Uh way to go on that I think right now the Pitman Motors that Are on the back of my my new robot uh They had it I think it was a six pin Connector on there it was like a single Inline connector so it had plus five and Ground and phase a and phase B and then The two motor leads also went through

There and somewhere along the line I cut The leads on the motor leads but I could Take it cut all those wires off and put Them onto the you know get the little Dupont connectors and just have those so They would plug in so I could Standardize on that I don't know if that Makes sense or not so Just just more things to more things to Think about there More things I would think separating the Uh The motor power from the encoder would Be a good idea It probably would yeah and technically Coming off the motor it's got like uh The two two power leads are twisted and Then the one's coming off the encoder Are you know four separate leads so They're technically not together at all It's just when they run for the Connector That's the way they decided to do that And on small motors it's not as big an Issue you get to big motors that it Starts to become more of an issue uh so Yeah that could be a problem So other than that Um well back to the black back to the Blue pill board Um It turns out there is a bootloader you Can load on this thing and I think I Think I have successfully treated this

Like an Arduino so you put that Bootloader on and then you can say Upload the code to this board and it Will do it you know through the USB Connector that's on here and then also When you load that bootloader then this This USB becomes like the the debug Interface on an Arduino so you can say Print and it will come out that and show Up on your screen so that so that that'd Be one thing it would be good to figure Out how to get that working and make Sure it's going to work and then track Down the various libraries uh some guy On The Homebrew robotics group has Created the quadrature decode function That will run on the blue pill board and He may or may not have treated like an Arduino I I'm not sure I don't remember And yeah I know I'm I'm thinking about Uh How to Use two serial outputs from my itsy Bitsy The one of them is for the uh Is on the USB that's serial zero But I want to be able to have a Communications to the Raspberry Pi And I don't want to do that through the USB Uh what was the deal on the Raspberry Pi Which which version of Raspberry Pi do You have 3B 3B okay because somewhere along the

Line uh on the version two they brought Up the two uh uart pins to the the pins On the edge but then when they moved on To the four was it four or three Does the three have the Wi-Fi built it Or the yeah Three three has Wi-Fi built in but it Also has uh transmit and receive Okay now the problem is when they added That chip for the Wi-Fi it's got the Wi-Fi and it's got the Bluetooth the Bluetooth uses serial and I believe the Bluetooth is connected to those two pins On the edge so Possibly just turning off the Bluetooth Now those pins will be available on the Raspberry Pi I don't remember the uh all The details behind that so you might Want to track that down when you when You go to do that look and see what they Say about that okay and it could be the Raspberry Pi four I thought they put a Newer bigger chip on that that could be You have more multi-function pins so you Might have more than what you are Available but I don't remember Rhino fan And and since if you don't have a four Already and I'm sure they're still real Expensive at this point so you know Don't don't don't hold your breath Waiting for that No I I don't have a four and it's got uh You are Transmit and uart receive for gpio pins

15 and 16. are you looking at it online What's its price Uh no I I've got a print out of the uh Raspberry Pi 3 Model B in j8 header And usually if you go looking for Raspberry Pi fours they'll just say They're out Simply say they're out of Stock they can go out on like Amazon and EBay and people charge you you know 100 To 200 is what they want for them Because apparently somebody's willing to Pay that Hmm But on the Raspberry Pi 4 I think if you Look at the gpio pins it may it may just Define them as the standard ones but if You dig harder it'll say oh well these Pins down here you could also I think There's maybe two I squared C channels On the thing and I was thinking there Might be up to four uarts whether to Bring them all out I don't remember but It's a matter of you know setting a Thing up and saying I want to Define These as say a uart as opposed to IO or Something So that's that's just something you Might run into on that okay And the other option is if uh your your Itsy bitsy boy that's kind of you that's Got a USB on that Yes it does because you can plug a USB Cable into that unplug that into Raspberry Pi and talk to it that way too

So that works out it basically works the Same way it's just you've got it's Hooked cable between it also makes it Easier when you go to program it because It's already connected If you're if you're able to program it Through your Raspberry Pi which uh Al Knows how to do all that stuff he's Playing with that platform IO or you Know you could probably just do a secure Shell or you could you could take your Hex file and download it do your eyes Right by and then there's a like a Command line Uh I think there's a command line Raspberry Pi function says program the Hex file into something so that again There's various ways to do that Typically I just just unplug the cable And plug it into something else and Program it and put it back the way it Was if I if I need to do that so Well I'm trying to get away from having To do that so yeah Pick the editor you like and more than Likely there's a plug-in to talk to Um To talk to it if uh happy to show you What I've done with this code but for my Own You know my my thought is to start with Just do whatever simplest and then you Know put it on the back burner and say Later I'm gonna have it so I can

Automatically program everything in Circuit Check right there I mean I Many a times I've gone back to the Arduino IDE and like I'm just gonna get It to work here and yeah And I I will have to bring up the story Of cray where they they they're building The super computers which is basically You got a box the size of a refrigerator And you have I think it had uh 32 8 24 18. 24 nodes inside of this box the size Of a refrigerator and a node was a Linux Processor and for each each processor You had a pick processor that did things Like turn the power on and off and Measured voltages and all this kind of Stuff and all the little power modules Had little pick processors everywhere so You get a big system and you end up with Say 40 000 microcontrollers in this box They said what let's the next time let's Make everything in circuit programmable So anyone they went to a lot of work Where you considered a a workstation at The side of the room and say I want to Update all the controller processors on Say a 40 I want to update 40 000 of Those and it goes out and broadcasts in Parallel says here reprogram these and Go through and do that so so that Becomes real handy when you can do that Otherwise they'd have to you know take Take the open open the cabinet pull one

Of the boards out And then get the little uh the pick Microchip uh programmer so you hook it Up your laptop plug it into the little Connector on the board and program the Four the four pick processors that do That now if you wanted to do the power Supplies I think you had to pull those Out and program them some other way so It could get to be a real pain to do any Of that stuff because you know it's like Anything else you say oh we made this Change let's go program this entire room Full of devices they turn them all apart Reprogram so he says oh damn that we Should have put a three instead of a two In there and they said oh damn I'm never Gonna we could tear it all apart again And redo it also yeah that becomes Extremely handy to be able to program in Circuit like that Um oh the other thing you were you were Talking about using uart's connect stuff Together and I'm I'm back to the point Where I'm gonna have to make a new Remote control And I was thinking I'm by Sammy 2 I Ended up not using the Adafruit board I Had that board that was called like uh They called it uh Laura m0 feather board So it had a processor and a Laura chip On the board that was in a package you Know basically in a package like this And I it turns out that I wanted to have

Canned because I was trying to try to Duplicate the one on our industrial one At work so I I couldn't get that chip to Do it the m0 processor does not have the Can peripheral built in so I went I Bought a Teensy 3.2 and a feather Adapter and I bought a new feather board That's just the Laura radio I stacked All those together and put a can for a Can transceiver on it and I was able to Get that one to talk with can but this New one I don't care if it has can or Not so I'll take the extra board that I Was going to use for that and just Program it to be my row control and then Just have the two uart pins somewhere on That board because I think that's got Lots of extra uarts on it and that way I'll just have it talk from from that Board with uart to say To say one of these boards you know uh That that would be the way to do it so So but that little board from Adafruit I'll have to supply it with power I'll Have to have the two uart pins and then One or two signals coming out to control My e-stop circuit so that's something Else that I was I was just thinking about using Uarts to talk back and forth between Things And if I decide for some reason to have More than one low level controller I Decided connect all those together with

Uarts too because I prefer uarts over I Squared C because I squared C is a a Pain to get it to You know you got to Define your own Protocols and and you got to get it to Work and hopefully it does continue to Work so I I you know I'm old school I Would like to go to uart where you just Simply slam this out and the other end Will read it and everybody's everybody's Happy so And it's bi-directional that's the one Thing I don't like about spy which is There there's a master and slave yeah Yeah And actually on I squared C you can make Masters you can make multi-master or Master Slave on that too but so there's Lots of things you can do but I I just Prefer that you are where you know it's Definitely point to point and you can do A little extra screwing around you can Get it to do like multi-master on a Single pair of wires but that's that That's again that's just more screwing Around that I don't want to have to do If I if I don't really need to do that I Don't intend to do that At this point So that's that's all I got on that I Guess Anything else before we cut it off Okay sounds good to me my front yard's Full of snow again after it warmed up

And most of the snow had gone and then Boom we got 12 inches of snow so my my It's gonna be a while before I go out And drive around with my stuff so That's all I had to say about that