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NXT Telegraph: Smart Move
Before IMing, before email - and even before the telephone - the telegraph let you send and receive messages in Morse Code. The NXT Telegraph lets you quickly and easily send messages from one brick to another. And, you can do the whole set-up from configuring the bricks to downloading and uploading the programs in under 10 minutes. The sender uses the NXT buttons to send a dot (.) with the left button or a dash (-) with the enter button. Both of you can hear the dots (A at .2 seconds) and dashes (F at .3 seconds) and the message is displayed on the receiver's display screen. You can send any length of message you want. When the line is filled, it starts a new line. When the screen is filled, it waits a short time and then clears the screen and starts over. To make it easier to decode the message, and mark the end of a letter, I've added a symbol that Samuel F.B. Morse didn't have - a space. The sender hits the right button, you both hear the next highest F at .1 seconds, and the reciever sees a blank space on the screen ( ).If you and your friend are real whizzes at Morse Code you might not need it, but I find it useful. The video shows a sending brick transmitting the message HI NXTLOG (as in the picture) to a dedicated receiving brick. I did this as I only have one sound sensor. If you have 2 bricks and 2 sound sensors you both can send and recieve. In that case, cable the sound sensor on your brick to port 2 of your friend's bricks and vice versa. If you are alone with only one brick and one sound sensor, just cable the sensor into your own port 2 and you can see what you are typing and practice your Morse code skills. You can make any kind of stand you want, or no stand at all. You have lots of flexibility in attaching the sound sensor as well. The important thing is that is right up against your brick and cabled into the other guy's port 2. The left bottom picture shows a sturdy way to attach the sound sensor and the right one shows a very simple but workable method. it's up to you. See below for the NXT-G program and MyBlocks you need, and a brief discription of why the program works the way it does. I hope you try this project. it's really fun to fool around with.

Posted by:

 snabeli

Created:

 14 April 2010

Rate:

 

Tags:(?):

 smartmove, informationtransport, sound, code, telegraph, video

Programs

(The pricture shows the message PROGRAMS in Morse Code.) Download the MyBlocks SENDmessage (left) and RECEIVEmessage (right) into your MyBlock folder making sure they have the exact same names. Download the program Telegraph into your Default folder as usual. All three files are fully commented, so if you would like to learn how the program works in detail, just download them and read it. But for a brief explanation..The sound sensor cannot detect pitch but using the timer you can see how long a sound remains at a certain level. Since the dot is at .2 seconds and the dash at .3, the program can tell the difference and display the right symbol. Read RECEIVEmessage to learn more.

Comments

29 comments

  • a_friendly_balrog

  • why not just use bluetooth? it would probably be easier and could communicate from further away

  • Posted 1134 days and 18 hours ago


  • goodtimes321

  • cool project! Are they wireless?

  • Posted 1134 days and 14 hours ago


  • kaelan002

  • not very usefull

  • Posted 1134 days and 12 hours ago


  • NXTSTORMER

  • Good project. However, I would like to point out some things you could do better with it. First, the bricks have to be connected by a wire. That limits the "useability" of a telegraph, or anything really. So, my suggestion to you is to connect the bricks with bluetooth. Then, your friend could be quite a ways away. Also, perhaps you did this on purpose to challenge your morse code decoding skills, but, you might consider adding a decoder to it. Look at next comment for continuation.

  • Posted 1134 days and 8 hours ago


  • NXTSTORMER

  • For example, if you wished it, then it could decode the message for you. Finally, the messages are received and coded using a sound sensor. If someone yelled too loudly, it would pick that up and think that it is a dot, dash, or a space. So, again, you could use bluetooth to eliminate this problem. Bluetooth is a very useful tool. Overall though, good project. I hope that you can make it better; after all, that's what Lego's are for, right? Good luck on your next project. Happy building!

  • Posted 1134 days and 8 hours ago


  • snabeli

  • NXTSTORMER: I don't understand your decoding comment. The message is decoded by the receiving brick in clear dots and dashes on the screen. About bluetooth: my computer is old and doesn't have it and I have always been able to get the results I want using NXT-G and sensor data. I have seen it used exclusively for remote control, master/slave situations. (cont. on next comment)

  • Posted 1132 days and 23 hours ago


  • snabeli

  • NXTSTORMER: My understanding (which may be wrong) is that a brick can either be master or slave but not both. If that is true it would not work because, if you have 2 bricks and 2 sound sensors, both bricks can send and recieve. About sound: I have run this program with music in the background and people talking and it works great. Read the code to see how this program works in detail.

  • Posted 1132 days and 23 hours ago


  • robodude2000

  • Well, the concept is a good one, but the only problem is that this version is wired, thus severely limiting portability. I suggest using the Bluetooth feature for wireless. Of course, that would eliminate the classic idea "tapping a message across the wire." Maybe if you ordered the superlong NXT cord from the HiTechnic company (They made the gyro sensor, accelerometer, compass sensor) then the NXTs could stretch 90 cm apart from each other. Any way, great project.

  • Posted 1132 days and 5 hours ago


  • a_friendly_balrog

  • snabeli: Am I correct in assuming that you think only one NXT can send messages to the other with bluetooth? Because that is not correct(no offense). How it works is one NXT connects to another over its bluetooth line 1(or 2 or 3). On the other NXT, it will be shown as connected on line 0. I don't think I'm doing a very good job of explaining this, but anyway(continued on the next comment)

  • Posted 1130 days and 9 hours ago


  • a_friendly_balrog

  • (continued)The first NXT(which you connected to the other one via its bluetooth menu) will say that it is connected on line 1, and that is the line it will send messages on. The other one will say that it is connected on line 0, and that is the line it will send messages along. So both NXT's can send messages to each other. Sorry if you already knew this, but just thought I'd point it out.

  • Posted 1130 days and 9 hours ago


  • csor

  • Cool,but how and why did the sending nxt get colored black?

  • Posted 1130 days and 4 hours ago


  • NXTSTORMER

  • snabeli: what I meant when I said decode was that, for instance, you could press a button and then the text would be displayed and not the dots and dashes. Also, bluetooth does not have to be just a master and slave condition. If you connect one brick to the other, and then vise versa, both can communicate with each other. BTW I did look at the code and it appears you did well with it. I would switch though to bluetooth. Great Work!

  • Posted 1129 days and 12 hours ago


  • vcbh

  • were do you get a black nxt birck

  • Posted 1129 days and 8 hours ago


  • snabeli

  • a friendly balrog and NXTSTORMER, thanks for your explanation of bluetooth. I did think it was just a one-way master/slave situation. I guess I'll I have to break down one day and buy a dongle. BTW, in the video and the picture the 2 bricks are right next to each other to get it all in the same shot, but in reality they are connected with a 90cm cable - the super long one.

  • Posted 1127 days and 18 hours ago


  • NXTSTORMER

  • snabeli: You don't have to have a dongle. All you have to do is, assuming you know how to connect to bluetooth, connect one brick to the other, and then do the same thing only with the second brick connecting to the first brick. Hope this makes sense. I'm very glad to see you are open to suggestions.

    NXTSTORMER

  • Posted 1126 days and 12 hours ago


  • helenwheels950

  • Awesome! Defineately the best in the information category. so far. Yeah you could do this is bluetooth but I don't got it either. Why this is so great is because you use sound sensor data to transfer information. That is creative and fabulous use of sensor data! Keep it up!

  • Posted 1125 days and 9 hours ago


  • david_msnxt

  • Very impressive. Wonder what frequency range the NXT can differentiate. Maybe you could set it up to replay the same frequency it receives and see how accurately it replays the notes that were played in the first place.

  • Posted 1124 days and 7 hours ago


  • 3DBlenderRender

  • I haven't been on here for ages, but I'm glad to see that there are still a bunch of excellent creations being turned out. Your creation is quite good, and it would be really nice to try out.

  • Posted 1123 days and 8 hours ago


  • snabeli

  • NXTSTORMER, thanks but my computer doesnt have bluetooth that I can connect to. I am very comfortable with NXT-G but no nothing about bluetooth but I always like to learn new things. Can you recommend a book on bluetooth programming? I would appreciate it and it would tell me if it would be a good investment. Thanks again.

  • Posted 1123 days and 6 hours ago


  • snabeli

  • david msnxt, As I said above the sound sensor can NOT distinguish frequency, only voluume. This works because the reciever wait until it hears a sound greater than 95db, then enters a loop with a timer in it and ends when the sound drops to less than 93db. Then a series of range block deterermine how long the tone was and thus whether it was a dot, dash or space. Read the MyBlock for more.

  • Posted 1122 days and 14 hours ago


  • BigThor

  • Hey! I just discovered a cool thing you built into your program. If you type the letter V (..._) is sounds just like Beethoven's Fifth! Great!

  • Posted 1120 days and 2 hours ago


  • Dinoguy7719

  • Ha-ha! Very funny BigThor. Anyway, this is a cool project.

  • Posted 1119 days and 11 hours ago


  • a_friendly_balrog

  • snabeli: If I understand you correctly, you believe that the NXTs need a bluetooth connection from the computer. You only need Bluetooth on your computer if you want to download programs or use the remote control with it. The NXTs come with Bluetooth already on them. You do not need anything additional to use Bluetooth in your programs.

  • Posted 1119 days and 6 hours ago


  • snabeli

  • a friendly balroq, thank you very much! I am going to try that later today. And I just broke down and bought a dongle (at 50% off!) and it will arrive on the 11th. I think I might rewrite the Telegraph Station program using bluetooth instead of sound. Then you and your buddy can send silent Morse Code messages across enemy lines. Stay tuned! And I really appreciate your advice.

  • Posted 1111 days and 14 hours ago


  • I-am-a-ROBOT

  • its original, but not very funny.... Best luck the NXT time!

  • Posted 907 days and 13 hours ago


  • Alexanderkahn

  • thats nice! good thing I know morse codo that way i can use it!

  • Posted 893 days and 7 hours ago



  • milo-c

  • nice!!!!!!!!!!!!!!!!!

  • Posted 559 days and 12 hours ago


  • legowave440

  • They still use cw... in amateur radio! They communicate all around the world, without dependency on some weak system, (like cellular, internet, ect...)

  • Posted 506 days and 5 hours ago


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