LiuJiajia

Venture to build your own keychain pocket watch circuit

You can create your own keychain pocket watch circuit. Perhaps the most representative of this circuit is printed form, and we have departed from the classic rectangular or square design and have drawn as a circle. The diameter of the printed keychain pocket watch circuit board is 18 inches. Circle-shaped cut is quite laborious, but not impossible. Anyway, those who do not dare to cut the PCB with this form; they can simply use a basic 18 cm square PCB side with the picture that we propose in the center.

To build the keychain pocket watch PCB design you just use basic materials. Get tutorials that can be downloaded online in PDF format, and print the footsteps of our tutorial "How to build your own watch circuit."  The PCB can be built using the method explained here.

Components

The list of components we will be using is quite extensive, but fortunately it is low-cost components, so it is a project within reach of all budgets.

Once everything is in place, and before putting the ICs into the sockets, we can feed the little keychain pocket watch and check the output of each have 5V voltage regulator. We can also measure the voltage at the pins of the sockets in charge of each integrated feed, to avoid any unpleasant surprises. Between pins 7 and 14 of each 74HC164N should have 5V as well as between 5 and 14 pin socket for the microcontroller.

If all is well, we can integrate every part in place, taking care not to put them in the opposite direction. Below we will see how to program the microcontroller for top watch functionality.

The software

We saw how to develop the hardware, and now begin to see how to take advantage of this design, explaining each of the routines needed to transform that pile of components into something useful. We write software from scratch, explaining each of the keychain pocket watch project steps so that everyone can fully understand each of the routines, and thus be able to modify it. We decided to present versions of CCS PIC BASIC and every piece of code as a way to reach a greater number of readers.

We have resolved upon the mechanism that every second makes a pudding up (something that we will see in the next issue, using interrupts), we should write a routine (or function, if we use CCS) to update the display and "seconds" as appropriate. Each time determined a "flag" would be "1", and the main body of the program should update the time and display it in the display.

Each of the keychain pocket watch segments (and the decimal point) of each display is connected through a resistor that limits the current flowing through them, one of the outputs from the 74HC164N. These are connected in a "cascade", so that when a data "out" of one of them will be applied to the input of the next. This means that with only two pins (CLOCK and DATA) we can write the 4 displays.

Article Tags: Keychain Pocket Watch, Keychain Pocket, Pocket Watch

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