The post discusses a simple hospital room call bell circuit which can be installed in hospital patient rooms for allowing the patients to get a quick access to a medical representative or a nurse whenever in need, by simply pressing a call button at the bedside. The idea was requested by Mr. Willy.
The Circuit Request
Hi Mr. Swagatam Majumdar,
Its Willy from Goa,
I want to request to to make a patients room call bell to nurse station circuit
diagram for a 10 bedded hospital.
the circuit can be made as simple as possible with no false triggering and solid
state with no relays and individual reset switch at the nurse station
Thanking you in advance
The Circuit Design
In one of my previous posts I discussed a simple office call bell circuit for facilitating an easy and foolproof communication across the rooms and the headoffice.
In this post we discuss a call bell system for hospital installation in order to facilitate communication between the patients and the nurses who may situated in different rooms or destinations across the hospital premise.
Referring to the above shown hospital room call bell circuit, the idea may be understood as follows:
The transistor T1, T2 basically forms a transistorized latch circuit wherein a trigger at the base of T1 causes the circuit to hold into a latching mode, meaning a single momentary positive pulse at the base of T1 enables T1/T2 to go into a permanent conduction mode until the feed from R3 is grounded by pressing the reset button.
On pressing the button at the patent's end latches the circuit into conduction and causes a DC pulse to be sent through D2 to the connected DC bell.
The bell sounds loudly until the 1000uF capacitor is charged fully, after which the bell ceases to operate.
However the latching action keeps the RED LED switched ON along with the green LED which is supposed to be positioned in the patient's room beside the call button. This LED informs the patient regarding the call been sent and confirms regarding the same. The red LED intimates the nurse regarding the patient's room.
Identical stages as explained above may be repeated and installed for each of the rooms in the hospital for enabling the respective occupants to execute a foolproof interaction with the nurses rooms whenever the patient may be in need for help.
The reset button is provided for enabling the nurse to reset or restore the situation back to the switched OFF condition which also simultaneously tells the patient regarding the response from the nurse's room, so that the patient is able to anticipate the help being on the way.
Parts List for the proposed hospital call circuit
R1 = 100K
R2, R3, R4 = 4K7
C1 = 100uF/25V
D2 = 1N4007
T1 = BC547
T2 = TIP127
Hospital Room Call Bell Circuit using SCR