Guidence Needed for a simple project
mangotel
Posts: 2
I want to build a type of jewelry box where a RFID comes close to the box and the lid lifts open. When the RFID is moved out of range, the lid lowers back in place. I tried to attach a daft block diagram but was unsuccessful.
I'm thinking about using the RFID, an RFID serial reader (a range of 12 inches would be great), a small motor, and a battery (or set of batteries).
Although a 9VDC battery is shown, several C size batteries may be needed to extend the life of the battery or provide enough power to lift and close the lid.
I would guess the lid won't weigh any more than a couple of ounces.
The lid needs to be able to open at least 90 degrees. Maybe an adjustable range.
Is there something already built or designed in here, somewhere? I've looked around but am have some trouble locating anything I could use or adapt for this project.
I'm thinking about using the RFID, an RFID serial reader (a range of 12 inches would be great), a small motor, and a battery (or set of batteries).
Although a 9VDC battery is shown, several C size batteries may be needed to extend the life of the battery or provide enough power to lift and close the lid.
I would guess the lid won't weigh any more than a couple of ounces.
The lid needs to be able to open at least 90 degrees. Maybe an adjustable range.
Is there something already built or designed in here, somewhere? I've looked around but am have some trouble locating anything I could use or adapt for this project.
Comments
Your project sounds very similar to something I think "Microcontrolled" did a while back. You might send him a private message and see if he can offer some suggestions.
http://forums.parallax.com/member.php?54463-Microcontrolled
The quick answer is that Parallax sells everything you need to put this together. For a light lid, a servo motor would work. And parallax sells a number of RFID-related devices:
http://www.parallax.com/tabid/768/txtSearch/rfid/List/0/SortField/4/Default.aspx
I have built this a while back very similar to what you want: http://www.parallax.com/tabid/827/Default.aspx
I would suggest you use the Propeller chip for this project, not only because it is my personal preference, but because of it's abilities to prolong battery life. When you run the "waitcnt" command, it puts the chip in low power mode and shuts down until the time is up. A used 9 volt could last about a month like this, assuming the time intervals are 2 seconds. Your main source of power draw is going to be the RFID reader, which has a super-bright LED always on.
When it comes to programming, source code is worth 10,000 words (forget pictures!), so here is the source code I used for my original project: http://microcontrolled.com/RFIDbox1.0.zip
My box was a self-locking one that didn't automatically open, but if you wanted one that opened for you, you would probably have to let the servo control a rod that would raise and lower the lid. How you would position it to open at a 90 degree angle, I have no idea. However, if you just want it to lock like my box, then get a lock, cut the "arm" off of it, attach it to the top of the lid (so that when the lid is closed it goes in the lock), then insert the key into the lock, attach a servo to the key, put this setup in the bottom of the box just below the arm you attached to the top, and you are set. Then just close the box, rotate the servo by 90 degrees, and it's locked.
Triggering this by RFID isn't that hard, as the RFID drivers I used would pause program execution until a signal was received. So you could just set it to lock, then wait, then unlock, then wait, etc. Once you learn how the software works, hardware is not that difficult. I also used an LCD display, but that is purely optional. I used the Parallax RFID reader, BTW, not the read/write module, which uses a different syntax.
Hope this helps,
Microcontrolled
Wow, that is very generous of you to provide your code. Too bad mango-dude seems to be a one-hit wonder. Maybe your generosity will inspire him/her to respond in some way.
Well, probably so, or maybe he just doesn't check the forum that often, as he posted a visitor message 7 days after your response on his thread. BTW I really appreciate you thinking of me when you heard of this project. :-) Even if he is a "one hit wonder" I still hope he gets something out of this.
Thank you so much for your reply. Sorry I've been absent, but between getting a pink slip, Mom falling and now having to make arrangements to sell her house (in this lousy market) and getting her into a seniors home (which is like stuffing a cat into a paper bag) I've been a bit out of touch.
I'm still planning to work on this project between sending out resume after resume, but like Rosana Rosana Dana said, it just goes to show you, if it ain't one thing, it's another.
Thanks again for the info.
mangotel