Controlling access to secured areas has long been a challenge. The solution requires balancing many sometimes-conflicting factors.
This uniquely net-centric solution
(reference design) is built around the powerful TINI platform and iButtons® (keys) from Dallas Semiconductor. iButtons provide the
user the convenience of a "Touch and Go" entry, while TINI® provides Internet
connectivity for administration and key management. 
How do you use it? Simply press the reader (called a Blue Dot Receptor) with your iButton and you’re in. This simple procedure is fast, reliable and secure. The willful act of touching prevents eavesdropping or accidental activation.
The iButton is a sophisticated microchip with a unique identity, which is surrounded by a stainless steel shell. Its round shape integrates easily into a credential that fits the user’s lifestyle.
By leveraging the 10-Base-T network, each TINI can manage up to four access points and bringing them under centralized administration. The system can be expanded with additional TINI’s in effective cost increments. Additionally, each TINI keeps the access list locally for fast user response and can therefore operate even if the 10-Base-T network is down.
At each access point is a low cost 1-Wire door controller, which consists of a DS2409 (high side switch), DS2406 (addressable switch), LM555 (adjustable oscillator) and the BlueDot receptor (with LED) (DS9092L).
When an iButton is pressed to the Blue Dot
Receptor at the door entrance, TINI reads its 64-bit 1-Wire address and compares
to a local list of valid buttons. If there is a match, TINI activates the
electronic door strike over the 1-Wire net.
A good choice for the electronic door strikes is Securitorn’s UnLatch®. It is motorized, sized to a commercial door strike plate and easily installs into the door jam. TINI activates this strike with a short pulse on the UnLatch’s "Trigger" input. This smart strike then does the rest. (Note this strike will only work with cylindrical door lock sets.)
Using the DS2409 as a node ID on a 1-Wire net, the TINI can address different modules or doors. When addressed, the DS2409 opens either Channel A or Channel B allowing the TINI to see other devices connected to that channel. Internal registers in the DS2409 provide pseudo interrupt capability so that TINI can detect activity on the DS2409's sub-net without being connected to it. When an iButton is presented to the Blue Dot, it generates a presence pulse. This pulse triggers the interrupt register in the DS2409 to respond to the interrupt search from the TINI. An alternate method is standard polling of each door Blue Dot Receptor. This reference design utilizes the later method.
The DS2406 has two channels. Channel A is setup as an output to drive the relay. (A relay is suggested to provide isolation and support higher currents.) Channel B is setup as an input to read a switch (magnetic reed switches are commonly used for door status).
The LM555 (or any generic brand of 555 oscillator) is added to lessen the communication over the 1-Wire net. The LM555 will create pulses to drive the LED in accordance to the Blue Dot specification. Using the relay output of the DS2406 to pull down the Reset of the 555, the LED will be turned on as long as the relay is energized. The CTL output of the DS2409, when pulled low, will cause the 555 to hold the LED dark as long as it pulled low.
The Securitron UnLatch was chosen because of its compact design, ease of installation and built-in door status switch. For additional information, contact Mark Henderson at Securitron Magnalock Corp. Phone: 702-355-5625. To be compatible with the TINI unregulated power supply, request the +12V model.
The schematic and layout of a PCB that fits into a standard NEMA single gang box is provided.
The NetworkLockServlet has been tested with TINI 1.02 and TiniHttpServer0.14.
source /bin/TiniHttpServer
NetworkLockServlet: initwhich indicates that the NetworkLockServlet is up and running.
http://www.your_tini_url/NetworkLock.htmlThe log in page now appears.
Username = admin Password = tiniNote that both the username and password are case sensitive.
| Door LED blinking | Door lock is operational and is waiting for valid iButton. |
| Door LED ON | If a valid iButton is detected, access is granted and the door LED will stay ON for DOOR_OPEN_MILLIS millisecond. |
| Door LED OFF | Either the lock is disabled or invalid iButton is detected. In the case where an invalid iButton is detected, access is denied and the LED will stay OFF. The door will resume operation after DOOR_DISABLE_MILLIS millisecond. |