How an ATM gives you money
Put in a card, type a PIN and ask for cash. Watch the ATM check the PIN, the money in the account and the daily limit, then count out Rs 1000 and Rs 500 notes.
Core concept
An ATM is a digital system: it takes inputs (card, PIN, amount), checks them against the bank's computer, and only then gives outputs (cash, a new balance)
Topic: Digital systems
An ATM (automated teller machine) lets you take money out of your bank account at any time. It is a digital system that works like a computer: input, processing and output. You give it inputs: your card, your secret PIN and the amount you want. It sends them to the bank's computer, which processes them: is the PIN right? Is there enough money in the account? Is the amount within today's limit? Only if every check passes does the ATM give its outputs: notes, a receipt and a new balance. In this lab the ATM pays in Rs 1000 and Rs 500 notes and lets you take up to Rs 25000 a day.
What you will learn
- Name the inputs, processing and outputs of an ATM.
- Explain the checks an ATM makes before giving cash.
- Work out which notes an ATM gives for an amount.
- Use ATMs and cards safely.
Before you start
- Add and subtract amounts of money in rupees.
Materials
- Pretend bank cards and paper notes for role play
Equipment
- None (never practise with a real card and PIN)
Procedure
- Take out Rs 1500 and record.
- Take out Rs 12500 and record.
- Type a wrong PIN and record.
- Ask for Rs 30000 and record.
- With only Rs 5000 in the account, ask for Rs 7000 and record.
How this simulation is simplified
- The ATM gives Rs 1000 and Rs 500 notes, as many Rs 1000 notes as it can.
- The daily limit is Rs 25000.