Homework #10

 ATM Machine

Fig. 1: An Automated Teller Machine (ATM)

The first Automatic Teller Machine or ATM was built in New York City in 1939. But the present form has been evolved in last 20 years. An ATM is also known as Automated Teller, Cash Point, Banking Machine or Money Machine. It is highly sophisticated engineering marvel accessible to everybody for telling a person’s banking information, payments and withdrawing him the money he demands.

Construction & Working

Apart from the technology for money withdrawal, an ATM is equipped with state of the art security system that guarantees a safe and secure transaction and renders the machine pretty much impregnable.

The procedure begins by insertion of an ATM card by the card holder. The magnetic tape on the card is read by two sensors. The first sensor checks for genuineness of the card, while the second one reads the bank account number and password for onward matching with password manually keyed in.

Fig. 2: Card reading sensors

Once the password is confirmed the ATM connects to the bank's network which gives machine its marching orders and remotely controls access to the on board vault. The trays in the vault hold bills with different denominations with up to a thousand bills in each. One tray is left empty for deposits.

Fig. 3: Money in vault

The cheque or money deposited with an envelope goes into a bin and is manually sorted later.  Some ATMs can take the deposits without an envelope. They are able to count the incoming bills and refill themselves.

For withdrawals, vacuum driven suction cups grab one bill at a time and feed it to a roller system. Drawing one bill at a time from the vault, prevents the machine from over payment.

The bills pass through rollers with sensors to check their length, width and the thickness of the bill about the size of a coating of paint. If it senses the bill thicker, it is considered as two bills stuck while any thinner, tells the machine that the bill is worn or fake and sends it to the reject bin. That’s when the user hears a pause during a counting sound. The transaction is recorded by the bank and the machine is ordered to release the card.

Fig. 4: A bill passing through rollers

Security

The ATMs construction involves more than a 100 kg steel which makes it heavy and impregnable. The machine is able to withstand 22 tons of impact. The vaults are designed in a way that they can survive an assault for a time long enough till the police arrives. In the event of a breach of vault security, there are explosive canisters of die that explode and ruin the money inside as soon as the vault seals are broken. There is also an on-board GPS to track the machine in the event of robbery.