Manual 99-minute countdown timer

By byoy (conmajia@gmail.com)

Time: May, 2012

Cover pictures are original in byoy; Do not reference them without permission

 

Download source code

 

Note: Because RTOS is used and there is no idle at any time, the power consumption is amazing,

The new 9 V battery is about 10 ~ 30 minutes. If you plan to use this design,

It is best to add power-saving code (power-down if nothing happens), or simply insert

AC (9 V, vro available)

-------- Looks wonderful ------

Playing single-chip microcomputer means controlling everything with single-chip microcomputer. What functions are required for timer?

1. timed

It can be scheduled to be very general. You need to determine how long the range is, 1 hour? 1 day? 1 year? 1 life? (Laugh)

In addition, for our fans to do things, we have to check the devices in our hands. For example, I have only one 7-segment tube and 16x2 liquid crystal.

I just made a simple timer. Can't I use LCD? So we decided to use 7-segment Pipe

Whether it's cooking or applying a mask or taking a bath, 99 minutes is enough, and only 2 7 tubes, 20 PIN,

Repeat the data and consume 10 pin Single-Chip Microcomputer

2. the time can be modified.

What do you think is the usefulness of a timer that cannot be modified? That's a time bomb ..

So we need to modify the time. How many buttons are required? Without reusing buttons

I think 3 are better. "Ten Minutes", "One minute", and "OK 」

3. Time reminder

Reminders are required when the time is up.

I have a choppy buzzer, 9 ~ 15 V, sound is huge, after the test, the 5 V power supply sound is still very large, but in a acceptable degree

4. Quick and simple development

The simplest method is to use RTOS, And the Keil comes with rtx51tiny.

So we started to design

------ Design comes --------

Circuit Diagram (if you can't see it clearly, the source code contains the. DSN File, just open it with Proteus)

 

 

It doesn't matter if you select a single-chip microcomputer Model, because all source code is based on standard 8051.

373 is used to lock the digital display, but it can be removed completely.

In addition, the digital tube does not have a traffic limiting resistor, and the brightness is very high (very high, dazzling)

In terms of software, the idea is very simple. Use the button to set the number of minutes (0-99), determine the Start countdown, re-determine the pause, and re-determine to continue

The buttons except "OK" are invalid during the countdown process. Alarm triggered by the buzzer after the time arrives. Press any key to stop the alarm and reset the time.

If you do not press for a long time, the system will automatically stop after how many sound sounds (to avoid power loss)

That's simple.

As a result, we began to make a hand-made presentation of the omnipotent cave Board (we can see that the digital tube is still very bright, and the battery is new)

 

 

No photo is taken on the back of the link. All the photos are flushed and flying. Refer to this figure.

 

 

Because the battery cannot find the battery cap, I made a DIY one, like this.

 

 

After debugging is complete, attach the Panel made of hard paper Shells

 

 

Finally, paste a piece of gift paper on the outside for the sake of beauty! (Note that the battery is out of power and the words are vague)

 

 

In general, because there is no power-saving design, You have to plug in the power when using it .. Power port reserved during design

 

 

Close the job. The machine size is about the fist size.

It is actually a very simple thing.

According to my calculations, if 373 is saved and 7805 is switched to the switch power supply, the software will sleep after timing every second,

In this way, a battery should be used continuously for one whole day)

 

To improve our creativity and make life fun, we can make it like this.

You can also

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