countdown timer

[cjn566]

how could i build or buy a module that when triggered would count down a specified amount of time, then change state?

 

[blueroomelectronics]

A microcontroller can do this. What sort of delay do you need?

 

[mark_3094]

Don't know if this will be useful or not, but here is a schematic that used a segment display to count up or down.
Changing the values of RC timing for the 555 IC will change how fast it counts up/down.
You can cascade additional 4029 IC's to allow for more displays.
I guess it depends on how accurate you want it. probably not the best if you want very accurate timing.

 

[cjn566]

building a coffee maker. when i press a button, the circuit will count enough time to brew a cup (3 to 6 min, tba). preferrably adjustable, but not necessary. Then it will trigger a solenoid valve to drain the pot into a cup for 5 to 10 sec.

 

[Mikebits]

building a coffee maker. when i press a button, the circuit will count enough time to brew a cup (3 to 6 min, tba). preferrably adjustable, but not necessary. Then it will trigger a solenoid valve to drain the pot into a cup for 5 to 10 sec.

This sort of thing would best be done with a Microcontroller as Blueroom mentioned. Then you can add all sorts of features and options abd flexability for future upgrades.

 

[cjn566]

Allrighty. So how would I use a mirocontroller?