He was going to make himself a small table clock. There are enough hours in the house, but in the dark, you need to turn on the light to find out the time, etc. So you needed a watch on the LED indicator with bright large numbers. On the site, Aliexpress found it, suitable in terms of parameters and price (72r). It consists of a finished printed circuit board and radio components that must be soldered according to the scheme.
The supply voltage of the watch is 3-6 V, the current consumption is 40 mA. Thus, they can be powered even from USB, a rechargeable battery from a mobile phone, a cell phone charger, or from any suitable power source.
This article describes how do it yourself make and customize LED clock with alarm.
See the entire manufacturing process in the video:
The list of tools and materials
- set C51 ();
- screwdriver;
- scissors;
- soldering iron;
- cambric;
- rechargeable battery from a cell phone;
- connecting wires;
- box with a transparent lid;
- black cardboard from packaging;
- Chargers from a cell phone.
Step one. Wiring the circuit board of the watch.
The main element of the watch is the ATMEL chip AT89C2051-24PC. It is mounted on the adapter pad soldered to the circuit board. The size of the printed circuit board itself is 52x42 mm, the size of the LED screen is 52x20 mm.
The wiring of the elements is simple - the installation locations of the parts and their symbols are well shown on the printed circuit board. In the process of assembling the clock is very useful device «third hand"Which I described earlier.
The sequence of desoldering the elements I had was like this: first we solder the resistors, capacitors and other components of the circuit except the controller and the LED indicator. At the end, unsolder the microcircuit and the clock screen.
Second step. Assembly of LED watches.
After soldering, it is necessary to check the printed circuit board (if there is any accidental contact of solder on adjacent contact tracks). The dimensions of the board are small, and this can happen.
If everything is normal, we supply power through the terminal strip. My watch went right away. The numbers on the screen lit up brightly, two dots in the middle blinked (second indication). It remains to come up with a watch case. I found a plastic packing box with a transparent lid (from some souvenirs). I drilled a hole on the side and installed a jack for the charger. Inside the box will be a battery from an old cell phone. By the size of a transparent cover, I cut a blank from black cardboard and installed it inside. In cardboard we cut a window to the size of the LED indicator and two holes for the pushers of the clock settings buttons. On the buttons we put on the tubes extenders from the ballpoint pen rod. From the foam cut out a piece to fix the battery and the printed circuit board, install inside the box and close the lid. I sealed the lid on the sides with a piece of transparent tape. All construction is ready.
Step three. Clock setting.
It remains to adjust the clock. This is done with the buttons S1, S2. A long press of the S1 button leads to the settings menu; it consists of nine submenus - A, B, C, D, E, F, G, H, I. The settings are selected using the S1 button, and the values themselves with the S2 button.
Types of clock settings.
A-hours \ B-minutes \ C-signal of each hour \ D-first alarm On \ Of \ E-first alarm, hours \ F-first alarm, minutes \ G-second alarm, On \ Of \ H-second alarm, hours \ I-second alarm clock, minutes
If the power fails, the clock settings are not saved, this can be eliminated with a 3V battery and a pair of diodes.
It’s up to any beginner to make such a watch on his own and it won’t lead to big expenses of time and finances.
A couple of hours of free time and 73 rubles (.) Went to all the work. The charger from the old cell phone and the battery are free. But in the house there was a new useful gadget.