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This kit contains a clock with date, day and alarm functions. All SMD components are already mounted on the two PCBs. The construction of this device is therefore possible without any problems even for people with little soldering experience. |
Introduction to HandsMagic's ‘diy clock type1’
The end result of an hour of tinkering
In the picture below, you can see the rather odd end result of an hour of tinkering. The ‘diy clock type1’ comes in a plastic housing that belongs in an industrial environment rather than in your living room. But...tastes differ, of course, and maybe you will like it! The case measures 11.5 cm by 9.0 cm by 5.5 cm. The right side has two openings for connecting a USB-A connector or a standard 2.1 mm x 5.5 mm power connector. The clock is indeed powered from 5.0 Vdc. Behind the transparent front panel is a PCB on which you will find fourteen identical LED seven-segment indicators plus an 8-by-8-pixel alphanumeric display. On this, the number of the day appears. As a joke, however, Sunday is represented by a heart. Between the hour, minute and second displays are four red LEDs that flash in a one-second rhythm.
Below the displays are five small pushbuttons, which allow you to set the time and alarm time. A larger pushbutton on the right lets you turn off the displays.
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| The look of HandsMagic's ‘diy clock type1’. (© AliExpress, edit 2024 Jos Verstraten) |
Manufacturer, suppliers and price
This building kit was developed by HandsMagic, a Chinese company that has several nice DIY kits on offer, including some Tesla coils. The company sells its products through AliExpress and Amazon. This ‘diy clock type1’ is offered to new AliExpress customers for an introductory price of € 25.29 with free shipping. If you already have an account with AliExpress, you will pay € 32.19 for it. You can also order the same kit through Amazon, but you will pay € 29.00 for it plus € 5.50 shipping.
Delivery of the kit
All small electronic components are well packed in the clock's case, so no pins of the ICs or displays can bend. In addition to this filled case, four flat ribbon cables and a long USB-A to USB-A cable are supplied. There is also a 5 Vdc mains power supply in the box, but it has an American plug and is therefore unusable.
The delivered components
In the picture below, all the components supplied are neatly arranged. You can see that the kit contains two PCBs, which are already equipped with all SMD components.
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| The supplied components of the kit. (© AliExpress) |
Again, no manual!
Following bad Chinese custom, this kit also comes without a paper manual. However, the package does contain a piece of paper with a QR code that links to an internet page on the supplier's site where you can find a few pictures that should help you build this clock.
The circuit boards
The two PCBs are shown in the picture below. On the left PCB, two ICs are already mounted plus some smaller stuff. You have to install the microprocessor and the real-time clock module yourself via the IC sockets. On the right PCB, five SMD chips are soldered. Both PCBs are connected by no less than four flat ribbon cables!
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| The component side of the two PCBs. (© 2024 Jos Verstraten) |
The electronics in this ‘diy clock type1’
No circuit diagram found
Of almost all Chinese kits we present on this blog, we manage to find the circuit diagram somewhere on the internet. We did not succeed in doing so for this clock. We must therefore confine ourselves to a brief discussion of the ICs present.
The left timer board
On the left PCB (see picture above) we discover a CH340 and a 74HCT138D. There is room for an STC89C52RC microcontroller and a real-time clock module DS12C887 from Dallas. That CH340 is a USB to RS232, RS485 and RS422 data converter. Apparently, the data lines on the USB-A connector are also active and it is possible to reprogram the firmware of this clock via this USB-A connector.
The 74HCT138D is a demultiplexer/multiplexer from three inputs to eight outputs. Since there are also a number of transistors under this IC, this IC will probably have something to do with driving the segments of the seven-segment displays in multiplexed operation.
The real-time clock module DS12C887 from Dallas
This kit uses a so-called ‘real-time clock module’. Dallas' DS12C887 includes a clock with calendar, a daily alarm and 114 bytes of static RAM. This module integrates an accurate quartz crystal and lithium backup battery in a 24-pin DIP enclosure. The date is automatically adjusted at the end of the month for months with less than 31 days, including correction for leap years. If a power supply failure is detected, the module automatically switches to the lithium cell. Thus, the clock remains synchronised.
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| Dallas' real-time clock module DS12C887. (© Analog Devices) |
The right-hand display PCB
Four pieces of 74HC573D and one 74HC245D are fitted on this PCB. The 74HC573D is an eight-bit type-D transparent latch. The 74HC245 is an eight-bit wide transceiver designed for bidirectional data transfer between two data buses. So there is not much information about the operation of this calendar clock from here.
Building the ‘diy clock type1’
Assembling the timer PCB
The recommended sequence is:
- The diode 1N4148 (D1), note the polarity.
- The 12 MHz crystal Y3.
- The 11.05 MHz crystal Y1.
- The resistor array RP1.
- The resistor array RP2.
- IC socket IC1.
- IC socket IC5.
- The 100 μF electrolytic capacitor C11, note the polarity.
- The 100 μF electrolytic capacitor C9, note the polarity.
- The four PCB headers JP1, JP2, JP3 and JP4. Here you absolutely must pay attention to how you solder these on the PCB. These parts have one upstanding edge in which there are two slots. On the PCB drawing we have marked with a red line where this upstanding edge should be.
- The buzzer BEEL1, note the side where the plus should go.
- The USB-A connector USB1.
- The power connector J1.
Finally, push the microprocessor and the real-time clock module into the IC sockets. In the picture below, you can see the final result of the assembly of this PCB.
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| The completely assembled timer PCB. (© 2024 Jos Verstraten) |
Assemble the display PCB
- Solder the five red LEDs and the one green LED. Pay attention to the polarity; the longest connecting wire is the anode or plus.
- Solder the fourteen identical seven-segment displays. Pay attention to the location of the decimal point here.
- Solder the 8 x 8 dot display, the side with the text imprint should face the side where the push buttons are located on the PCB.
- Solder the six push buttons.
This step of the clock's construction is represented in the picture below.
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| The completely assembled display PCB. (© 2024 Jos Verstraten) |
Mounting the PCB headers on the display board
Now turn the display board over and mount the four PCB headers on the solder side of this board. Solder the pins onto the component side. Use a thin soldering tip, because you have to solder between the displays! Again, pay very close attention to the position in which you have to mount these components. The photo below shows this clearly. We have again shown the position of the upstanding edge in which the two slots are located with a red line.
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Mounting the PCB headers on the solder side of the display PCB. (© 2024 Jos Verstraten) |
Connecting the two boards
Before incorporating the whole thing into the enclosure, you obviously need to test the clock. You need to connect both PCBs with the four flat ribbon cables provided. Also in this step, you must of course pay very close attention to which PCB headers you need to connect together. So take a moment to study the picture below.
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| Connecting the four flat ribbon cables. (© 2024 Jos Verstraten) |
Working with the ‘diy clock type1’
Power supply
You can power your clock from any mains power supply capable of supplying 1 A current at a voltage of 5.0 Vdc.
The function of switch S6
This switch allows you to put the clock into a sleep mode, where the clock continues to count, but the displays are extinguished. Only the right-hand red LED D3 then remains lit.
Synchronising the date and time
- Press S6 to make the clock active.
- Use S1 to select what you want to adjust: seconds, minutes, hours, days, months, year or weekday. The corresponding display flashes.
- With S2 and S3, you can synchronise the selected display with the current date and time.
- Press S1 again to select the next display unit.
- You have to go through all seven possible settings. Finally, the weekday is set on the 8 x 8 display. Day seven, Sunday, is represented by a heart.
- Press S1 again to save the settings.
The function of switch S5
Pressing this button returns the display to the last data displayed before you started setting.
Setting the alarm time
- Press S4.
- Use S1 to select the seconds, minutes or hours display.
- Set the desired alarm times with S2 and S3.
- Press S4 again.
- The alarm time is stored in memory.
Switching off alarm
Press any key to switch off the alarm.
What if the power supply fails?
Then, of course, all displays go out but because of the presence of a lithium cell in the DS12C887 real-time clock module, the clock continues to count. When the power is switched back on, the actual time is displayed again.
Installation the clock in the casing
Screw the timer board to the bottom of the enclosure using the four short screws. Pay attention to the correct position so that the two connectors are accessible through the holes in the housing.
Press the white rubber sealing strip into the slot in the back of the case lid.
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| Mounting the PCBs in the box. (© 2024 Jos Verstraten) |
Mount the display PCB over the four bolts protruding from the case cover. Note the position of the switches!
Screw the PCB tight with the four M3 nuts provided.
Screw on the cover with the four bolts provided.
Buy this multi-function clock at Amazon
