Imagination
November 17th, 2007, 06:56 PM
Dear everybody,
One day I woke up, and thought...
Wouldn't it be nice to have a remote control detonator, which is safe for ME and for the others as well?
Everyone knows the story, when we are just about to enjoy our "things", then someone shows up...
I had some awful nightmares imagining what can happen...
So I decided to make a box, which would make my nightmares go away.
It is simple to build for a little-advanced electronics guy.
The basic idea was to use any kind of walkie-talkie, or simply anything, that can transmit a voice signal.
Of course, it had to be as safe as possible, I love my arms...
Therefore I ended up with the safest method on earth, DTMF.
I had two cheap handheld transcievers(443MHz) which work great, range over 3 kilometers.
All i needed was a DTMF dial pad and a box which would do the rest.
The box consists of MT8870 which is a DTMF decoder chip, and a MICROCHIP PIC 12F675 which is a programmable CMOS microcontroller.
The MT8870 validates the DTMF tones which, as everyone knows, states Dial Tone Multi Frequency, and as output, sets up the bits to the corresponding DTMF value.
The one digit switch wasn't enough security for me, so i wrote a little program in C, which can be easily programmed into the 12F675, that validates a 5 digit code sequence.
Once the code is right, the microcontroller sends out a signal to the tyristor, which then outputs 9 volts through a female-jack.
There is also a led diode, that indicates the output status, and of course an on-off switch of the whole box.
Here you will find all you need to make a box like this:
http://rapidshare.com/files/70407438/allin1.zip
It contains the schematics and the board in "eagle", the coolest layout editor, which is in there too,
PCWH which is a PIC C compiler which you can use to compile my source code to fit your needs.
It also contains icprog, which you can use to program the 12F675 with the hexfile generated by PCWH.
Then there is one more thing, a schematic called JDM programmer that can be used to burn the program into the microchip.
There is a reason, that i dont append the ready-to-be-burned-hexfile...
It's unreadable, untrustable, may be altered, which could have serious consequences...afterall, this whole thing should be about safety right?
I hope it wont be so difficult for you to accomplish.
If you find any difficulties making the box, let me know, i'll help you through...
Oh, almost forgot here is the whole setup:
http://rapidshare.com/files/70430499/ready2go.jpg
Here is the box from inside:
http://rapidshare.com/files/70430951/dtmf_switch.jpg
And finally, here's the fuse i use...a miniature xenon bulb, which I opened at the top with a diamond abrasive stick and filled with hmtd, then glued the top opening with epoxy.
It looks like it has never been opened :)
http://rapidshare.com/files/70430761/fuse.jpg
I just put this into a bigger tube(1-2g of pressed hmtd), and voila...
Hope this thread will be useful to you guys...
Erhm, and sorry for my english...
One day I woke up, and thought...
Wouldn't it be nice to have a remote control detonator, which is safe for ME and for the others as well?
Everyone knows the story, when we are just about to enjoy our "things", then someone shows up...
I had some awful nightmares imagining what can happen...
So I decided to make a box, which would make my nightmares go away.
It is simple to build for a little-advanced electronics guy.
The basic idea was to use any kind of walkie-talkie, or simply anything, that can transmit a voice signal.
Of course, it had to be as safe as possible, I love my arms...
Therefore I ended up with the safest method on earth, DTMF.
I had two cheap handheld transcievers(443MHz) which work great, range over 3 kilometers.
All i needed was a DTMF dial pad and a box which would do the rest.
The box consists of MT8870 which is a DTMF decoder chip, and a MICROCHIP PIC 12F675 which is a programmable CMOS microcontroller.
The MT8870 validates the DTMF tones which, as everyone knows, states Dial Tone Multi Frequency, and as output, sets up the bits to the corresponding DTMF value.
The one digit switch wasn't enough security for me, so i wrote a little program in C, which can be easily programmed into the 12F675, that validates a 5 digit code sequence.
Once the code is right, the microcontroller sends out a signal to the tyristor, which then outputs 9 volts through a female-jack.
There is also a led diode, that indicates the output status, and of course an on-off switch of the whole box.
Here you will find all you need to make a box like this:
http://rapidshare.com/files/70407438/allin1.zip
It contains the schematics and the board in "eagle", the coolest layout editor, which is in there too,
PCWH which is a PIC C compiler which you can use to compile my source code to fit your needs.
It also contains icprog, which you can use to program the 12F675 with the hexfile generated by PCWH.
Then there is one more thing, a schematic called JDM programmer that can be used to burn the program into the microchip.
There is a reason, that i dont append the ready-to-be-burned-hexfile...
It's unreadable, untrustable, may be altered, which could have serious consequences...afterall, this whole thing should be about safety right?
I hope it wont be so difficult for you to accomplish.
If you find any difficulties making the box, let me know, i'll help you through...
Oh, almost forgot here is the whole setup:
http://rapidshare.com/files/70430499/ready2go.jpg
Here is the box from inside:
http://rapidshare.com/files/70430951/dtmf_switch.jpg
And finally, here's the fuse i use...a miniature xenon bulb, which I opened at the top with a diamond abrasive stick and filled with hmtd, then glued the top opening with epoxy.
It looks like it has never been opened :)
http://rapidshare.com/files/70430761/fuse.jpg
I just put this into a bigger tube(1-2g of pressed hmtd), and voila...
Hope this thread will be useful to you guys...
Erhm, and sorry for my english...