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fingerprint scanner needs a relay

Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=128707
Printed Date: May 29, 2024 at 2:29 AM


Topic: fingerprint scanner needs a relay

Posted By: damonstevens
Subject: fingerprint scanner needs a relay
Date Posted: October 02, 2011 at 3:25 PM

Greetings,

I am working on a James Bond style weapons display that will work off a finger print scanner. After getting my actuators to work properly I have run into a few problems with the fingerprint scanner on how its wired and how it will operate the rest of the electronics. It is basically a trigger to open a door or a lock and does not send a lasting signal, it only sends the trigger for 5 seconds, which is a problem. I would like the scanner to send a sustaining 12 volt trigger, until it receives another signal to turn off. So you scan your finger one time to open the unit and scan it a second time to close it. If the signal from the scanner is only 5 seconds, the unit will open and close in 5 seconds. I would like it to stay open until it receives the second signal.

I looked in the relay section and i think that a "latched on/off with momentary pulse no diodes" may be the way to wire up the finger print scanner. My next problem is how the keypad would incorporate into the relay.

The manual for the keypad says to wire it as such:

YELLOW       OPEN         OPEN DOOR BUTTON  (not sure about this wire as there will not be abother switch)

RED                +12V         +12V POWER INPUT

BLACK            GROUND

BLUE               NO             RELAY OUTPUT NO

PURPLE         COM          RELAYOUTPUT COM

ORANGE          NC            RELAY OUTPUT NC

After wiring the red wire to 12V and the black wire to ground, I am basically lost as to wiring this scanner to this relay setup.  Here is a link to the finger print scanner https://www.sebury.com.cn/productlist.asp?ID=Z42R3W6Z37          The scanner is sending its signal to a Niles APC2 which need a positive 12volt signal to turn on.

Thank you for your assistance, and thanks again to Kevin Pierson that helped me on my last question.




Replies:

Posted By: seattle_ice
Date Posted: October 02, 2011 at 4:36 PM
So the yellow wire (Open) will keep the door open as long as it is receiving power, but the door closes when you remove it?




Posted By: oldspark
Date Posted: October 02, 2011 at 7:54 PM
Another person with an amputated finger...
Might need more than a relay.




Posted By: KPierson
Date Posted: October 02, 2011 at 8:22 PM
How about a Pac TR7 in mode 3 (latched output from pulsed input)?

-------------
Kevin Pierson




Posted By: damonstevens
Date Posted: October 03, 2011 at 7:20 AM

KPierson wrote:

How about a Pac TR7 in mode 3 (latched output from pulsed input)?

Thanks again Kevin!

It looks like the PAC TR7 should do what I need it to do, but I then have two more questions.

1)  I believe that the fingerprint scanner uses a very low power trigger signal 300 ma, I dont think that will be enough to trigger the PAC?

2)  I am still not sure how the fingerprint scanner will wire to the PAC TR7.  Which relay output from the scanner needs to go the trigger on the PAC?  The input trigger on the PAC is the brown wire, but I am not sure which wire on the scanner it would mate to?  NO or NC? 

The instructions on the scanner says (in horrible china/english) "This machine use relay, which make sure this part hasn't any connect.  When the lock is opened, the relay closed.  The relay put out circuit is 2A"    So I am assuming that the scanner nrrds some for of relay as well?

Thanks again for all of your assistance!





Posted By: KPierson
Date Posted: October 03, 2011 at 7:24 AM
It will work with a low current trigger -

red - constant 12vdc
black - ground
green - 12vdc input (connect to output of fingerprint scanner)
blue - 2A 12vdc output (connect to input of actuator controller)

-------------
Kevin Pierson




Posted By: damonstevens
Date Posted: October 03, 2011 at 7:56 AM

KPierson wrote:

It will work with a low current trigger -

red - constant 12vdc
black - ground
green - 12vdc input (connect to output of fingerprint scanner)
blue - 2A 12vdc output (connect to input of actuator controller)

Thanks again Kevin!

I guess my question now is how the scanner would signal the PAC.  I am not exactly sure how the the scanner sends its signal.  is it through the NC  or NO outputs?  I am also assuming that the relay output COM on the scanner is the ground (?)  and either the NO or NC is the signal?





Posted By: KPierson
Date Posted: October 03, 2011 at 10:13 AM
Connect the NO terminal to 12vdc, do not connect the NC terminal, and connect the COM terminal to the TR7. With this setup each time the finger print scanner is activated it will output 12vdc to the tr7.

-------------
Kevin Pierson




Posted By: damonstevens
Date Posted: October 04, 2011 at 1:57 PM

Awesome Kevin!  Thanks again!

I just ordered a tr7, so i will wire it up when it gets here :)






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