If you want anybody to provide more constructive help you are going to have provide some details of exactly what you are trying to achieve, also details of any external circuitry you might be trying to interface with.
How accurate do you need your 40 second delay to be ?, if it's not critical try googling "555 monostable".
SYC has good points. A monostable flip flop set for 40 seconds would be suitable for use in a toy. The 40 second accuracy would be subject to power supply voltage, capacitor tolerance, capacitor temperature drift, capacitor aging, capacitor current leakage, electrical noise etc, etc..
If you need high accuracy, use a stable oscillator and countdown circuits.