For the Hams on Board

@robo-pi

I figure that the only way you're going to get into trouble is if your signal is actually interfering with other devices and people start reporting it.  Only then would someone be sent out to investigate the source of the problem.

On one sunny day on the Solent on the south coast of England, somebody was creating a carrier wave on the emergency channel 16 but not broadcasting. So using triangulation they figured out the position of the perpetrator. So an RNLI RIB was dispatched to investigate. Two things should be noted before I carry on with this anecdote (source Yachting Monthly true story).

1. The wives of yacht club commodores are not generally spring chickens.

2. The Brits are almost as prudish as the Americans when it comes to exposed breasts.

Nevertheless. The wife of the commodore had taken their yacht out onto the water to do a bit of topless sunbathing. So when the RNLI guys arrived, on the foredeck was a topless middle-aged lady and in the cockpit was an Old English Sheepdog with the microphone in its mouth.

Robo, I guess you can make up a little ditty about this. ?

Posted by: @robo-pi

I'm not sure what a 433Mhz signal would interfere with in my rural area. 

The take out my wireless digital thermometers!  They too run on 433MHz.  Remember, 433MHz probably means 433 to 444MHz. I'm not sure. They say 433MHz on them. I also live in a bit of a rural area (look at the picture on my website - back yard with a small garden), and I have a couple of them outside in the trees, one in front of the house and the other in the back.  I set up two Arduinos and left them "talking" to each other for a few hours.  I noticed both of my thermometers were not updating.  I unhooked the TX Arduino, and everything went back to normal. So, either they were on the same frequency as the thermometers, or they are RF noisy and broadband.  They are made in China and a dime a dozen, so I don't think they are much in the field of spectral purity! ?

Unrelated, get your ham license.  It will open a ton of doors, and you'll have a lot of fun.  Unless things have changed, all you need are 3 Extra class Hams to administer the test.  Almost all Ham Radio clubs have these designated examiners.  The FCC got out of the giving exams business 20-25 years ago as well.  I could have got a US Extra class license when at a Ham club in Hawaii in 2005, but I didn't have a US mailing address.  All I would have had to do was rent a PO box in Honolulu, but I didn't see the point of tying up NH6DX or whatever if I wasn't ever going to operate from there.  You don't have to be a US citizen to have a US Ham license.  

Posted by: @pugwash

Robo, I guess you can make up a little ditty about this.

You must want to get me banned from the forums. ? 

A ditty about an ity bitty t----y?

I'll think I'll pass on that one.

I could write something up about the microphone being a dog bone though. ? 

Posted by: @ve1dx

Unrelated, get your ham license.  It will open a ton of doors, and you'll have a lot of fun. 

I'll be looking into it.  Right now I better go work on my truck.  I'm replacing the clutch and I'm only just now starting to reassemble everything.

Posted by: @robo-pi

Right now I better go work on my truck.  I'm replacing the clutch and

It sounds like you are a busy guy, what with the mechanic work, the boiler project, etc.  I replaced one clutch about 45 years ago.  It wasn't easy. ?  Anyhow, keep the priorities in order.  Arduinos and Ham radio licenses will be around longer than we are, no doubt.  Oh, thanks for the poetry, BTW.

I finally dug up the schematic for my breadboards.  That's cool.  Now I won't need to try to figured everything out again from scratch.

I still can't upload pictures on this forum, but I can upload them elsewhere so I did that and just link to them.

Just as an added note.  I used 6 opto isolators between the Arduino pins and everything on the breadboard.  I was doing this in part just for fun and to experiment with the opto isolators.   I'm also using a 74HC595 Shift Register on the 7-segment display so I don't need to use a lot of Arduino pins to drive that.   The RF board and 7-seg display are driving by a separate 5v power supply I only show the connector for that at the bottom of the schematic.

I drew this schematic up in TinyCad and the artwork for the transmitter and receiver were also custom made in the Tiny Cad component library.  I also made up the diagram for the relay that switches between the transmit and receive modes.   I'm just using a very small 5v relay that plugs right into the breadboard.

Now I need to go and see if I can find the code I was using.  Hopefully I can have something up and running by the end of the week.   I notice the date on this drawing is Aug 2015.  So this was a project from 4 years ago.  That's not unusual around here.  I must have a couple dozen breadboards laying around with unfinished projects on them. That's typically how I work.  ? 

Four years later and I'm finally getting around to firing these things up.

I can't find any of the original code I had.  But I don't think I got very far.   I think all I did was have the relay turning each unit on and off and maybe something to send out numbers to the 7-seg display.  But I don't think I had much done toward trying to send data out the transmitter or reading it back in from the receiver.

I do recall though that I wanted to learn the details so rather than just downloading and using a library to do this I was going to try something along the lines of what Kevin Darrah was doing in this video.

That might seem kind of crazy, but like I say, at the time I was more interested in learning exactly how the data is sent and received so I didn't want to just use a library that would do all that for me.   I still feel the same way today.  I'd still like to learn the nuts and bolts of it.

Although I might try a library too just to see how that works.

In any case, this is where I'm current at right now.  I'm going to try to set these boards back up and see if I can get everything operational again.   At least in terms of getting all the LEDs and Relay working the way it's supposed to.  Then I'll be ready to try to send some bytes through the actual radio waves.

This is exciting.  I know I could probably use other RF devices, but I'd really like to get these up and running and see how they work.  After all, I already have them built.  May as well get them up and running.

@robo-pi

That might seem kind of crazy, but like I say, at the time I was more interested in learning exactly how the data is sent and received so I didn't want to just use a library that would do all that for me.   I still feel the same way today.  I'd still like to learn the nuts and bolts of it.

I fully understand where you are coming from on this, that is why I spent so much time trying to get the RTC to react to direct commands, i.e. without libraries, over I2C. And the video provides a pretty good insight into the basic workings of digital RF.

But I still don't believe that this is a long term solution to controlling a robot. My guess is that if you are planning on two or more robots being controlled simultaneously and in real-time, then you are going to have to shovel lots of data back and forward.

That is why I suggested you take a look at the 2.1GHz module I mentioned above.

Although not available to Joe Public yet, we already have 5G installed here in its test phase, predominantly controlling dozens of autonomous container carrying vehicles in three container terminals. There was quite an interesting TV program recently on this subject, especially interesting were the collision avoidance systems, generally, emergency systems in case some truck driver, not on the container terminal radar, gets lost and ends up in the operating areas for the container carriers.

A robot with no purpose and too much AI will eventually get up to mischief. ? 

Posted by: @pugwash

That is why I suggested you take a look at the 2.1GHz module I mentioned above.

I'm not carved in stone on anything yet.  I just want to play with these 433Mhz modules since I already have them set up to go.  I also have about a dozen or so pairs of these modules.  Apparently I bought a whole batch of them some years ago.  So if I can get these up and running I might be able to use them on other projects around here as well.

But yeah, I'm open to other possibilities as well.  I won't be needing long-range robot communication for quite some time anyway.   It's just something I foresee a need for at a later date as I know my current WiFi connection has distance limitations.

Posted by: @pugwash

A robot with no purpose and too much AI will eventually get up to mischief.

Just like these radio boards I've recently returned to working on an old A.I. program I started.   This is  A.I. based on semantics (i.e. the conceptual meaning of words).   In fact, I prefer to refer to is as R.I. because if successful it would be "Real Intelligence" and not artificial intelligence.   By that I mean that the robot would actually understand what it's talking about.   Of course, I'm not alone in this approach.  These ideas have been around for a long time. 

It's funny because when I got this old program back out I was dreading having to relearn where I had left off.  In fact, this concern was probably preventing me from returning to it sooner.   However, as it turns out, I was not only able to get right back into it fairly quickly, but I've come to realize that I have also acquired a lot of new ideas in the interim.   So I not only have the program back  up and running, but I'm currently making improvement to it at warp speed.  So this is really cool.

I guess I owe Bill an extreme debt  of gratitude for his DroneBot Worshop channel and for having created this forum.  Even though I had been watching many other YouTube channels, Bill has really inspired me to get all this stuff back out and breathe new life back into it.    I think that when  he started the DB1 series is what did it for me.  He said it's about time that he actually build that robot that he had been putting off.  So I figured the same is true here.  At 70 years old it's basically now  or never!  You can only procrastinate so long and then  you die. ? 

@robo-pi

 At 70 years old it's basically now  or never!  You can only procrastinate so long and then you die.

I am not far behind you. ? ? 

Just thought I'd post a bit of an update.

My 433Mhz Boards

I finally found a little bit of time to sit down and take a closer look at these breadboards I had built some 4 years ago.    One of them fired right up and the program is still in the Arduino.   Apparently I had it simply count from 1 to 3 on the 7-seg display and then momentarily switch the receive off and the transmitter on for a few seconds.  Then it switches back to receiver mode and starts counting to 3 again.   I'm pretty sure that's all it does.  I don't think it actually tries to transmit any data.   Although I really can't remember.  I wrote this code 4 years ago and I can't find a copy of the source code anywhere.  It's probably on one of my computers somewhere but no luck finding it.   It's not a big deal as I can easily figure out how to make it do what it's already doing.   I also checked the Serial Monitor for possible prompts or info, but apparently I didn't have it send anything to the serial monitor.

The second board I can't test because I had apparently erased the code on that Arduino and uploaded code to save data to an SD card.   So I'll need to write some new cod and get these two boards back in order.

On the Ham Radio License

Tonight was the first night I had a chance to look into this.  I found a really nice video series where a Ham Operator gives lessons by going through the Ham Radio Manual page-by-page.   So I'll be following that video series along.  If anyone else is interested let me know and I'll post a link to his first video.

His first instruction was to buy the Ham Radio Manual that he'll be going through.   His video is slightly outdated as he was saying to be sure to get the most up-to-date manual that he had which he says only goes 2010 to 2014.  I think he video was made in 2011.   In any case I went to Amazon and found the manual for about $15.   But then I decided to see if I can find a free PDF of it and sure enough I did.  So I downloaded that instead along with a few other PDFs along the same lines.

Finally, I went through some of the exam questions.   Certainly not all of them.  But of the ones I did look at I knew the answers.   Most are general electronics questions and questions about frequency, etc.   So I know all that stuff already.  The only questions I'll need to study up on will probably be more related to Ham Radio rules.  Most of the physics and electronics I already know.

In any case, I'm starting down this path toward getting a Technician license.  No rush.  I'm going to take my good old time.  I'm not in any hurry to get the license.  So I'll just wait until I feel really confident that I can easily pass the exam and then look for a place where I can take it.  It might be this fall, or winter, or not until next spring, but I'll get it eventually.    I just follow this fellow's video course along and answer every question in the book until I have them all answered.   However long that takes.  No rush.

It will be cool to finally get the Ham license though.   As I have already said, my main purpose is to be able to build my own radio equipment for robot communication and legally use more than just 100 mW of power.

Although once I get the license I might also take a stab at getting "on-air" just to say I did it. ? 

I'll probably build my own transmitter for that too.  Because that's what Technicians do. ? 

@robo-pi

Way to go James!

Since you have the electronics background, I'd suggest you go ahead and take the exam for the General class license as well, provided of course you pass the Technician level.  Most test sessions have a fee around $15 to administer the exam. If you pass, they will usually let you take the General exam for no additional charge (and it's not that much harder if you have a good electronics background).  And if you pass that one too then you could try the Extra class.  Now it is much tougher, but I've been a VE (Volunteer Examiner) at several session where someone has gone from no license to Amateur Extra all in one sitting.

The current Technician Class pool of questions is for the period 07/01/2018 to 06/30/2022.

The current General Class pool of questions is for the period 07/01/2019 to 06/30/2023.

The current Extra Class pool of questions is for the period 07/01/2016 to 06/30/2020.

No question pools get updated in 2021, then the cycle of upgrades starts over again in 2022.

So you could go from unlicensed to Extra Class in one day for just one $15 fee.  The license itself is free and renewable every 10 years, also free.

Here is an ARRL link where you can take practice exams:  ARRL Practice Exams.  I recommend it to the students that attend my licensing classes. 

Good Luck!

Posted by: @codecage

So you could go from unlicensed to Extra Class in one day for just one $15 fee.  The license itself is free and renewable every 10 years, also free.

Exactly!  With the elimination of the Morse Code requirement, getting to the top level in most countries now just requires moderate technical knowledge and an understanding of the rules and regulations.  While I was mostly a CW (Morse Code) operator when I was active, I felt eliminating it as a necessity was a good thing.  Why? Because it's hard (or impossible) for some people to learn.  Having to send and receive Morse Code at a fast clip was a barrier that kept many good people out of the hobby.  For example, you might have had a Ph.D. in Electrical Engineering in 1985, but if you couldn't send and receive CW at 21 WPM (send by hand and receive by ear), you couldn't be a Ham.  

Not everyone agreed, and there were "wars" fought over the code requirement.  Ultimately the no-code side won, and that was a good thing.  Here's a humorous story about the CW War written by a friend of mine in Florida some years ago if you have 5 minutes:

http://www.zzoomworks.com/kh2d/opinions/article.cfm-id=4.html

He says Ham Radio is brain dead.  It's not, but if you read his ramblings, you'll see how divisive the Morse Code issue was.  It went on for a decade or more.

Posted by: @codecage

So you could go from unlicensed to Extra Class in one day for just one $15 fee.  The license itself is free and renewable every 10 years, also free.

I didn't know this.  That's interesting.  It would be cool to come home with an Extra Class license.  If only because that would allow me to have more frequencies to choose from.

Like I say, I'm in no rush, I'll probably take the test sometime over the winter.  So I've got plenty of time to study up for it.  I can see from the questions that the Technician class license appears to be a breeze.  Like you say I could most likely pass the General Class as well.   If I study up I might be able to take the Extra Class too.

That would be cool.  I didn't know that you could do that.  I thought you might need some time under your belt between classes.  So I'll prepare for the Extra Class exam and see how far I get.  Based on what you say I'm willing to bet that I'll at least be able to grab the General Class.  I think that alone opens up a lot more frequencies than the Technician class is permitted to use.  

@robo-pi

I does open up a lot more frequencies, but only in the HF bands.  For what your are planning for robot work, Tech is all that is needed.

Going on to Extra class only opens up a few more HF frequencies.  Some of that could actually show up as questions on an exam.