An electronic die - throwing circuit can add a new twist to some classic board games.
The specific electronic die circuit which is presented here is small and simple, and has a single integrated circuit 4060. The 4060 is a 14-stage ripple carry binary counter, and contains an internal oscillator. The oscillator needs only two resistors (the R1 and R2) and a capacitor (C1) in order to generate the clock signal. The counter is advanced one count on the negative transition of each clock pulse, and can be reset asynchronously (independent of clock) to the zero state by a logical “1” at the reset input.
While counting, the counter toggles every Q output pin at a rate which is an exact fraction of the oscillator frequency. The QD output (pin 7) toggles at a rate which is equal to the oscillator frequency divided by 23 = 8. QE toggles at a rate equal to the oscillator frequency divided by 24=16, QF at a frequency equal to the oscillator frequency divided by 25=32, and so on. State changes of the Q outputs generate a binary counting sequence.
A rolling-die has six possible states, thus we need at least 3 digits (bits) to represent these states (see. table). Of course, 3 digits correspond to 8 (23 = 8) different states, and we need only 6 of them. Counting from 0 to 5 is what we need, so, we use D8, D9 and R6 to reset the counter when reaches at 6. Thus, the counter counts from 0 (000) up to 5 (101) and resets at the 6th state (110).
The LEDs are arranged in an appropriate way to represent all numbers on a rolling die. For better understanding of the connections between the LED and the counter, you may think that apart from number 1, there are always two LEDs lit in order to represent any other number on the die. This means that we have to control only 3 pairs of LEDs and a single LED at the center of the arrangement. In every pair, the two LEDs are connected in series.
The circuit can be powered from a 9V battery and power consumption varies from 15mA to 40mA, depending on how many LED are turned on. A new number is displayed on the die after each press of Sw1. Sw1 is a normally-on push-button. This means that the button is a closed switch at rest, and an open circuit when being pressed.
Normally, the clock signal is grounded through the switch and the counter remains idle. During button press, the switch opens and allows the oscillator signal to trigger the counter. Then, the counter starts counting, and as the clock cycles are counted, the LEDs flicker and the die is ‘rolled’. The counter stops as soon as the user stops pressing the button. When the counter stops, the electronic die can be in any of the states shown on the table provided below.
Table 1 (Counter states)
| State |
Pins 4 - 5- 7
|
Die number |
|---|---|---|
| 0 |
0- 0 -0
|
5
|
| 1 |
0 -0- 1
|
3
|
| 2 |
0 -1- 0
|
6
|
| 3 |
0- 1- 1
|
1
|
| 4 |
1- 0- 0
|
4
|
| 5 |
1- 0- 1
|
2
|
Construction
For making construction easy, we have designed a small PCB. The only thing you have to do to make your electronic die, is to solder all the components on the provided PCB. It is essential to take some special care when handling the CMOS semiconductor.
All resistors used in this project are all ¼ watt, 5% tolerance, or better. The capacitors are all common low voltage ceramics. The circuit is powered from an ordinary 9V battery. This type off battery is usually designated as NEDA 1604, IEC 6F22 and "Ever Ready" type PP3 (zinc-carbon) or MN1604 6LR61 (alkaline). The battery is connected to the PCB through the P1, 9V-battery clip.
