CONSTRUCTOR LED hourglass

The electronic hourglass is a DIY kit consisting of 57 blue light-emitting diodes (LEDs). The device visually represents the passage of time by simulating the flow of sand in a traditional hourglass: one LED is illuminated at a time in a sequential pattern. All timing and control functions are handled by an onboard microcontroller. A push-button allows the user, with each press, to increase or decrease the display speed.

Supply voltage: 5 V DC Board dimensions (mm): 84 × 40 × 10

Assembly and Use

For proper assembly of the kit, it is recommended to start with the components having the lowest profile (smallest height). First, solder the IC socket (plinth), paying close attention to its orientation and polarity reference marks. Then proceed with the slide switch, the push-button switch, and finally the LEDs.

In the case of the LEDs, correct polarity is crucial. Make sure that the anode and cathode of each LED are oriented properly according to the PCB markings. If any LED is soldered in reverse, some of the LEDs may not light or may operate incorrectly during normal use.

Bill of Materials (BOM)

• L1 ÷ L57: 3 mm blue LED
• U1: 8 + 8 pin DIP socket with STC15W201S microcontroller fitted
• S1: slide switch (power selector)
• S2: tactile microswitch (speed adjustment button)
• DC1: DC power jack
• ISP: 4-pin male header (in-system programming connector)

Power Supply and Start-up

After completing the assembly, power the product with a 5 V DC supply through the DC1 connector. The center pin of DC1 is positive. Alternatively, you may solder two wires directly to the two pads located between the DC1 connector and the S1 slide switch:

• With the DC1 connector oriented on the right-hand side, the left pad is positive (+),
• The right pad is negative (–).

If the device does not power up, check that the slide switch S1 is set to the ON position.

Push-button S2 can be used to adjust the apparent “flow of time” by changing the LED scan speed. Each press increases or decreases the scrolling speed according to the programmed sequence.

Technical Summary

Electronic hourglass kit consisting of 57 blue LEDs that mark the passage of time by simulating the sand flow of a traditional hourglass. The effect is obtained by sequentially lighting a single LED at a time. The system is controlled by a microcontroller, and a push-button allows the user to modify the indication speed. The unit operates from a 5 V DC supply and the PCB dimensions are 84 × 40 × 10 mm.