Circuit to generate a signal a specific time after a trigger event. The timing can be defined by an RC time constant, or by clock pulses from an oscillator.
5
votes
3answers
465 views
0-10 second on-time with a potentiometer
I would like to make a simple circuit, where the a potentiometer controls a 0 - 10 second on-time.
If the potentiometer is set to min, the on time should be 0 seconds. If the potentiometer is maxed ...
4
votes
4answers
789 views
Maximum attainable delay with Micro controller
I am designing a microcontroller based delay circuit to implement delays of 2 hours, 1 hour, 45 minutes, and 30 minutes. The circuit will automatically turn on off a relay after this time period has ...
3
votes
4answers
336 views
Delayed power supply startup
I would like to make a circuit that turns on a power supply to a microcontroller after holding down a button for a period of time (say 2 seconds). To make matters slightly more complicated, if ...
4
votes
5answers
958 views
Random time timer
I'm constructing a simple circuit that beeps a beeper on a given time interval, using a 555 timer. Is there any simple way to randomize the time on the 555 timer between two given intervals, say, any ...
5
votes
3answers
439 views
Which of these approaches for a watchdog timer?
I recently learned about watchdog timers, and am trying to implement one for my circuit for the purpose of resetting my (AVR) microcontroller if it hangs (i.e., doesn't respond to the watchdog).
...
3
votes
6answers
773 views
General directions for a timer circuit which will not use microcontroller and which can measure several hours needed
Some background info first:
In my country, price of electricity depends among other things on the time of the day when energy is used. Because of that, many people tend to turn on big energy consumers ...
7
votes
6answers
1k views
6 Month Countdown Timer Circuit
I need to design a timing circuit. After a duration of 6 months a LED must come on. The LED can then be turned off at the press of a button and the 6 month count-down must begin again. Anyone have ...
3
votes
2answers
201 views
Use USB as an on-off switch
I'm looking for a way to build a zero(ish) cost intervalometer for my Canon SLR using only stuff that I have or can get very cheaply (my budget is about $4). I've already managed to "build" a wired ...
3
votes
3answers
1k views
purpose of diode in this 555 timer application
I'm a newbie in electronics.
I need to make a 555 timer base circuit(Refer to the schematic below) such that O/P pin of 555 is held LOW by default at power on, and the I/P pin is held initially at ...
3
votes
3answers
374 views
Suggest a timer chip
I need to take voltage measurements separated by long delays (couple of hours) and beep a buzzer when voltage level is met.
Power consumption is important.
What i want is a simple timer chip like ...
2
votes
4answers
171 views
I need help designing a very simple timer
I'm designing a very simple led light timer based on the Pomodoro time management technique. For those of you unfamiliar, you work for a set amount of time, take a short break, and repeat.
My end ...
2
votes
1answer
2k views
C18 Timer0 timing calculation using MCC18
I am programming a PIC18F4520 and I've set it to use a 32Mhz internal clock.
I need a counter to tick every second so I'm using TMR0 for this purpose.
To use ...
2
votes
1answer
1k views
What is the purpose resistors and capacitor in this 555 circuit?
What is the purpose of the capacitor , the resistor , and the variable resistor ?
Do they work like clock pulses for the 555 timer?
0
votes
3answers
282 views
Does this timer circuit make sense?
I want to make a timer that counts down from 15 minutes, in 5 minute intervals.
It should use 3 LEDs, and behavious should be such that when it is switched on, all 3 LEDs are lit. Then after 5 mins ...
