EK028 Electronic Dice
Part.no: 41024599
A clever little soldering kit with LEDs and a digital counter circuit that together form an electronic dice.
When the push button on the side is pressed, the dice rolls, and as soon as the button is released, the result of the roll is displayed using the LEDs. After a short time, the LEDs turn off to conserve power.
The circuit is implemented in four separate functions. A high-frequency clock signal is generated by two transistors configured as an astable multivibrator. The clock signal is fed into a 10-stage decade counter. The outputs from the counter are combined using simple diode logic to drive the LEDs. The fourth function is an automatic shutdown with gradual dimming of the LEDs.
The kit is supplied as two printed circuit boards connected by four copper traces. For a simpler assembly process, the components can be soldered and the boards left connected. Solder wires to V+ and GND and the dice is ready for use. For a more advanced build, the boards can be separated and assembled using spacers. With a battery holder and coin cell battery mounted on the underside, the dice becomes a self-contained unit ready for use at any time.
The push button can also be replaced with a tilt switch, allowing the dice to be activated by shaking or tilting.
Compatible tilt switch is available as an optional part.
The dice is power with a CR2032 battery (sold separately).
- Supply voltage: 3 – 12VDC
- Automatic shutdown time: ~15s
- PCB dimensions: 38.1 x 38.1mm (each part) / 38.1 x 77.5mm (full size)
Component list
| RefDes | Value | Qty. | Part.no. | Marking |
|---|---|---|---|---|
| C1, C2 | Ceramic capacitor 47nF | 2 | 40500044 | 473 |
| C3, C5 | El.lyt capacitor 10uF | 2 | 41017674 | 10uF |
| C4 | Ceramic capacitor 100nF | 1 | 41015538 | 104 |
| D1 - D10 | Diode 1N4148 | 10 | 40310010 | |
| LED1 - LED7 | LED 5mm red | 7 | 40307020 | |
| R1 - R8, R11 | Resistor 1kohm | 9 | 40811310 | |
| R9, R10, R12 | Resistor 47kohm | 3 | 40811447 | |
| R13 | Resistor 2.2Mohm | 1 | 40811622 | |
| SW | Push button 6mm right-angle | 1 | 41013367 | |
| T1, T2 | Transistor NPN BC547 | 2 | 40320001 | BC547C |
| T3 | Transistor FET 2N7000 | 1 | 40327000 | 2N7000 |
| U1 | Decade counter 4017B | 1 | 40360038 | CD4017BE |
| VIN | Pin header 2.54mm 1x2-pol | 1 | 41001167 | |
| Battery holder CR2032 | 1 | 41003391 | ||
| Screw M2.5 6mm | 4 | 41010778 | ||
| Spacer screw M2.5 10mm | 4 | 41014099 | ||
| Spacer M2.5 10mm | 4 | 41014104 |
Assembly guide
Before starting assembly, verify that the printed circuit board is free from damage and scratches. Check that all components to be installed are present and compare with the component list.
The printed circuit board for EK028 is supplied as a combined panel with two sections that can be separated. It is recommended to keep the boards connected during assembly and test the functionality before separating them.
All components except the battery holder are to be mounted on the top side of the board. Start with the lowest-profile components and from the center of the board. Finish with the tallest components.
Ensure that components are placed in the correct positions and, for polarity-sensitive components, with the correct orientation. Follow the markings on the board.
If the dice is to be powered by a coin cell battery, the battery holder must be mounted on the underside of the board.
The solder joints may be difficult to access. Take care to avoid contact between the soldering iron and already installed components, as this may cause them to melt.
Once the battery holder is installed (or wires have been connected to the holes marked V+ and GND), the functionality can be tested.
When the button is pressed, the LEDs will light up and flicker. As soon as the button is released, the dice will display the result with 1, 2, 3, 4, 5, or 6 illuminated LEDs.
The dice will automatically turn off after a short time.
To achieve a more dice-like form factor, the two PCB sections can be separated and instead assembled vertically.
Break the boards apart and remove the connecting tabs using side cutters.
Attach the spacers to the board with the LEDs using screws. Then fasten the lower board to the spacers.
Note the markings at the mounting holes. The hole with the square copper pad must be oriented in the same direction on both boards (the white arrow).
Instead of the push button, a tilt switch can be installed. This allows the dice to be activated by shaking or tilting it.
The tilt switch should be mounted in the same holes as the push button, as shown in the image above. Compatible tilt switch is available as an optional part.
Interactive assembly guide ↗
Simulation ↗
Schematic
Drawing
