50 ibuttons at once

Hello everyone im new to arduino, and i got this idea, really usefull if you get where to use it, i usually work with 700 ibuttons (1990A-F5 Dallas) but they usually get lost by ppl, so i need to do a quick scan of 50 aprox. at once know if some key is missing if it possible to know which one is it, i think that would have to go with the C code, so i got this crazy idea i do need a ibutton prober, so i build a some sort of spider web and got all of them joined with only one output and that one output maybe a rj11 goes to an arduino board then that arduino goes to pc and i see the info on the screen, is this possible? which arduino board could help me? i dont want to buy everything done, i want to build it and make it work, i got the tools and some knowledge for c programming, i need some guidence with this part.

Thanks a lot for reading, sorry bout my bad english, im from chile still learning, and why do i post this here and not at the spanish forum? dunno got the idea i would get more answers and help here.


This may help.

i usually work with 700 ibuttons (1990A-F5 Dallas) but they usually get lost by ppl

Not sure what you mean by. PPL.

Also are you saying that you have a system already working that has 700 iButton readers?

You seem to be proposing a system with 50 readers, instead of 700.

How many readers will you have, how far from the arduino will they be?

Do you propose to have all 50 readers on the same single wire?

ppl = people, i think.

I think he wants to just swing the buttons, in a bunch, over the reader?

I'll take a stab at the guessing game.

ppl is Pennsylvania Power and Light. (at least here on the East coast it is)

have 700 iButtons that people use all day and then put back. all are serial number devices.

you take one, put in your ID into the reader, then swipe a button. now, it is linked to you for that day.

you have access with that button to anything you are allowed to have access to, doors, executive bathroom, the computer, whatever.

at the end of your shift, you put it back. of course remembering to swipe it back into inventory.

so, a quick read of the ones in inventory will show what ones are there and what ones have not been returned. also, to zero out the ones people forgot to log back into inventory.

how did I do ?

Kinda close, (ppl = people) sorry about it, used to write fast and shot, ill try to explain myself the best i can, we are going to buy 700 ibuttons pcs, 1 per worker, after day is gone they gonna have to place it in a hold/probe slot, and it will be 50 ports per bag, all connected to a single port, and that one will be connected to the arduino and will tell that ibutton id 00000 is missing or connected o ie. 45 ibuttons detected, 5 missing, missings are: bla bla bla... i hope u could understand me, thanks for the replys so far, and well if there's a new idea, instead of using ibutton i.e those plugs for audio, following the same plan, 1 per worker.

PS: If i do it with ibutton, 1 button id 0000 would carry ie 2 keys, one for office 1 and the other for office 2. Ibutton id 0001 would carry 2 keys for car 1 and car 2, so if i see in arduino that ibutton with id 0001 is connected, it would say to me that keys for car 1 and 2 is there.

iButton is a 1 wire device with a chip that has a serial number.

to read, they have to be connected to that wire. the iButton readers have a ring on the outside for one terminal and the center is the other terminal.

to have 700 readers is kind of silly. you would be better to have one reader that unlocks the door and then that button goes into a slot that closes a contact.

presence is known by the timing of the door being opened, and then the contact changing state.

or, add an RFID tag to the iButton.