Electronics-Lab.com Blog

embedded-lab.com writes:

The goal of this project is to construct a simple 0-9999 seconds count down timer with an alarm and a display. The time is set through two tact switches and the count down seconds are displayed on a 4-digit seven segment LED display. The project uses PIC12F683 microcontroller for all I/O and timing operations and MAX7219 IC for driving the seven segment LED module. The time out condition is indicated by an audible alarm from a buzzer.

0-9999 seconds count down timer using PIC12F683 microcontroller - [Link]

Haris Andrianakis writes:

After some modifications on my UV exposure box (scanner) for better UV expose, i desided that a better pcb must me designed for switch timer. The old one had over drilled holes and it was designed and built on my very fist steps. Also the high voltage side from the low voltage wasn’t seperated as it needed to be safe.

So i redesigned it in a more compact and easier to use pcb. The firmware has been also updated and now you can program the timmer by using the two buttons. The time is calculated by timer interrupt triggering using a 32.768KHz RTC Crystal with better accuracy. The display update also has been changed from static to dynamic.

PCB Exposure Switch Timer V2.0 - [Link]

tehnikservice.net writes:

This is a good looking and practical device that can be useful in many areas where countdown timer is needed. This project is based on the PIC16F84A microcontroller. The time range can be adjusted between 1 and 999 seconds.   This project  has 3 buttons and one of them is named Set Button. In order to regulate the seconds up or down  on the display you should press the Set button while pressing the button on the  left or the right  hand side. The author of this project is @Pedja089. More photos on Facebook Fan Page.

Timer from 1 to 999s with PIC16F84A - [Link]

dselec.wordpress.com writes:

This is a countdown counter based on ATtiny2313, primary developed for my PCB exposure box, but it can be used for other purposes too.

The counting range is between 1 and 90 minutes and it can be adjusted with up or down buttons (high and low in the pictures).

After the desired time is set, the countdown starts by pressing the start/stop button (on/off in the pictures). By pressing the same button we can interrupt the counting at any time we want.

After the count expires we hear a beeping sound and the load is disconnected. By pressing start/stop button we reset the counter and we are ready for another lap. All actions included the time remaining are shown in the LCD display.

Pcb countdown timer - [Link]

Arduino CrossFit Timer - [via]

I was looking for, what I thought, was a simple clock/timer design.  Something with a remote and a big display that could be read from across the gym and that I could program with up/down counting but also intervals specific to CrossFit like Fight Gone Bad or tabatas.  I wanted to incorporate a bell to give it a gym feel and something that could be heard over loud music. This journey took me through many designs, chips, a custom board, wood working and a whole lot of learning!

Arduino CrossFit Timer - [Link]

Charalampos Andrianakis writes:

Two years ago i modified a scanner replacing its mechanism and all the internal electronics with UV lamps converting it to an UV exposure box for PCB prototyping. By the need of making my life easier and not waiting for the pcb to be exposured i designed an AVR timer to automatic switch off the lamps after 1 minute of exposure which was much enough for the PCBs. Here is the circuit

This was one of my first completed projects from design to production. As you can see the scheme isn’t that good and there have been by passed some capacitors at the power supply. But the circuit works with no problem.

AVR  Switch Timer - [Link]

kalshagar.wikispaces.com writes:

Goal is to replace this Ikea super cheap timer that works … well, as good as something manual that you paied less than 200 JPY (less than 2 euro). Not precise, sometimes doesn’t ring, or ring just the blink of an eye, so easy to miss…

The new timer will:

• Have a graphical LCD (bought one one year ago, never used it, needed a pretext, so…)
• Work on battery (1x 9v battery)
• Play music when it’s time
• Use a speaker and amp
• Possibly use a YMZ294 ?
• In fact something else but much better…
• Have an on/off system with a push-button, not a open/close switch In fact a tilt switch
• No arduino, but a simple atmega 328 (more than sufficient)
• Keep me busy a few days while allowing me to use some parts I bought long time ago and create a un-reasonable and out of price kitchen timer

Arduino KitchenTimer - [Link]

embedded-lab.com writes:

Last week I was browsing my old backup hard drive and I found a source code for a very simple PIC based digital timer that I made a couple of years ago. The actual hardware of the project isn’t with me anymore. I might have lost it when I moved from my old apartment into my new home. However, I thought this might be a good practice project for beginners and so I am sharing it here. I am not going to build it from scratch again; I will rather demonstrate it using my DIY PIC16F628A breadboard module and I/O board. The complete circuit diagram along with the firmware developed using mikroC Pro for PIC compiler is provided in the article.

00 to 99 minute timer using PIC16F628A microcontroller - [Link]

anonymouse197 writes:

This instructable will guide you through creating your own Arduino based Kitchen Timer. This is a quite simple project, requiring little or no programming or electronics knowledge, just the willingness to learn and fiddle – an ability most useful for modern man.

This kitchen timer is simple enough, press and hold a button and it will count up it multiples of five minutes, until you release the button. Upon doing so the timer will flash, and begin counting down. This timer includes an alarm and a display, with a piercing piezo buzzer to get your attention.

The arduino, laptop, protoshield, and USB Cable excluded; I took every electrical component from an old or broken device. Try to recycle things, its easy to get hold of broken electronics for free so make the most of it! See any jumpers on this design? No, paper clips are much better – cheap as chips and more sturdy too!

Arduino Kitchen Timer - [Link]

Features:

• No power supply needed: The circuit “steals” in the operating current (only 10µA at 5V and 2.5µA at 3.3V) from the signal lines of the camera
• Interval adjustable from 0.4 seconds to about 18 minutes
• No controls, setting of the intervall via “teach-in” from the camera
• Ultra-portable: the circuitry fits into the housing of a 2.5mm stereo plug
• Component cost: 87 ct (July 2010)

Intervall Timer for Nikon and Canon DSLR - [Link]