KeyBoard Transmitter

Hey everyone This is like my first real picaxe project so any destructive criticism would be very help full. I have finally started to built a robot but then i realized i had no way of controlling it over long distances or that regular rf modules would be lost around 20 feet. So I went to google and i soon discovered that people where used dtmf transceivers with fps walkie talkies to deliver data long distances. Thats how the keyboard was born I simply torn open a keyboard painted it black cut a hole for the lcd and wired a picaxe 28x1 to a dtmf tx chip and a dtmf rx chip. I also though later it could be used for other things than my robot such as remote rocket ignition or just talking to another keyboard.

The code for contraling the robot is almost done ill post it if you guys want me to

The robots reciver is almost done to Ill post i pic. I plan for a picaxe chip to take care of all the messy work then spit out to an microcontraller called a oopic via serial

the pic the jack going left to right power, Rx, Tx, Prog

THe robot is just a rc buggy with plexie glass bolted to the top
if any body want to know anymore about just ask.

Kk thanks for reading and any ideas on this type of Communication are cool

Tyler Berezowsky

ps this is like the nicest form I'v been to

ah sshoot

forgot the pictures

more

more photos

I also though later it could be used for other things than my robot such as remote rocket ignition

Seriously; DO NOT use this setup for rocket ignition. That topic would be best discussed in the Active Forum.

I there i was just thinking of comunication using also walkie talkies like that the ones that have 8 chanes plus 38 sub chanels at least here in portugal i think in other countris its diferent. but i realy new at how im i going to get the signal from the mic or teh speaker to make something that the picaxe can understand. I know i have do amplifie the signal. or something if you could give me the scmatics for that part of your project.

Sorry for any mistake on my words.

Thanks.

I didn't amplify the signal at all. I had the opposite problem I used a DTMF transceiver. It basically send out sounds that would go though the walkie talkies then on the other end another DTMF Transceiver to decode the signals. My problem was that the DTMF chip when transmitting put out so much voltage on the signal outline it would get distorted so i add a pot to stop that. If you search DTMF communication you'll most likely find the info you need.

Hope this helps you out, if you have any more question don't be afraid to ask, but im not the best at this stuff either so it would be best to post question in the main form where the real experts could help you out.

Good luck ,
Tyler Berezowsky

Ah nice... Going to give it a try... i was thinking on going on a more primitive way and try out diferente signals ant diferente distance do find out what band rate could i use with less problens and them try to make some protocol, i think its the way that i learn more, But theres always room do find out the DTMF transcever. I was wondering how would i produce a signal similiar to the mic with the pic and make him ear what comes out from the speaker. I with will be very ease ou more if i had ans osciloscope but the only one that i can use its here at work and is mix with the Diagnose Laptop and its always in use... lol

Oh wel i´m going to read all i can about it...

Thanks for the help.

Cya

I have search for DTMF and i realy had no idea thats how it works, But i i still have a few questions how do i mix two diferente frequencies at the same time? a low one and a high one i think its a stupid question but i´m not gething there maybe i didn´t understud something very well...

Thanks

DTMF tones can not be generated by a single picaxe. You could use picaxes one to generate each end of the tone but, I used a DTMF generator like the ones on this link to create the tones http://www.futurlec.com/cgi-bin/search/search.cgi
Try posting your question on the main form. Much more smarter people than me could help ya out.

And if you order from that site just as a warning if you order from futurlec there shipping takes very long (bout a month) to get to the U.S.

Thanks but i think that i´m Portugal Europe it takes a litle less, but i usualy order everything from UK it takes less to get to me then from my own country... and of course its a lot cheaper...

Yeah i get that idea just after writed the post lol. I just got to combine de two frequencies in the same wire. I think the more tricki part its to debug. in the other end. and cut all the noise... but i´m gona give it a try to de datasheet of the DTMF chip.. I´m just getting up imformation for the project. when i realy need il ask in the main forum and creat a thread. I dont have my laptop now :S send it to spain to the waranty a lot of dead pixels. it will take a 30 days to came back...

Thanks... Cya