Blog | Raspberry Pi
Some of the turnstiles have electronic capability to open a gate. Currently these are opened manually by a foot switch. The system will be upgraded to use an electronic switch operated by the Raspberry Pi.
A reed relay operated from a GPIO pin of the Pi will enable the reed relay. The normally open pins will be connected in parallel with the foot switch, thus allowing the Pi to enable the gate to open or the operator can do so.
COTO TECHNOLOGY 9007-05-01 RELAY, REED, SIP, SPST, 5VDC, DIODE
A GPIO pin will be enabled for output which will allow power to be provided across the relay part of the switch. thus enabling the contacts.
1 -- Footswitch 1
2 -- GPIO Output
3 -- GND
4 -- Footswitch 2
When GPIO output is set high the reed relay closes, making a connection between pins 1 and 4.