Be prepared to do some experimenting to get the results you want. This is especially true of circuits such as the Across Track Infrared Detection circuits and any other circuit that relies on other than direct electronic inputs, such as switches.
http://home.cogeco.ca/~rpaisley4/xCA4060B.html
http://www.discovercircuits.com/PDF-FILES/watchdog.pdf
count until it becomes the 0 seconds from the set time from the 1 minute to the 99 minutes.
http://www.hobby-elec.org/e_counter.htm
Count-down timer with PIC16F84A.
http://www.hobby-elec.org/e_pic6_3.htm
12-bit binary counter which used 4040B.
http://www.hobby-elec.org/e_ckt14.htm
do the operation of the relay in the constant time after pushing a start switch.
http://www.hobby-elec.org/e_ckt4.htm