Dice that roll themselves, from two chips

Hold the button and a seven LED die face flickers through faces. Let go and it stops on one. A 555, a counter and six diodes.

Free build sheet

The parts, every wire with its length and bend points, a bend guide, both sides of the board and checkboxes to track your progress. Print it or keep it open at the bench.

Open the build sheet

What you need

25 parts on a perfboard 23 × 43 holes, plus hookup wire.

Qty	Part	Where to buy
1	Ceramic Cap100nF C1	Buy Ceramic Cap on Amazon
6	Diode (axial) D1, D2, D3, D4, D5, D6
1	Power Input (2-pin) J1
7	LED LED1, LED2, LED3, LED4, LED5, LED6, LED7	Buy LED on Amazon
3	Resistor (axial)2.2k R1, R3, R4	Buy Resistor (axial) on Amazon
1	Resistor (axial)2.7k R2	Buy Resistor (axial) on Amazon
1	Resistor (axial)100k R5	Buy Resistor (axial) on Amazon
1	Resistor (axial)10k R6	Buy Resistor (axial) on Amazon
1	Resistor (axial)47k R7	Buy Resistor (axial) on Amazon
1	DIP-16 U1
1	Tactile Button 6mm U2
1	DIP-8 U3

Check every pin against the datasheet of the exact part in your hands before wiring.

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Cut list

36 wires, 1312 mm (51.7 in) in total, in the order the build sheet cuts them. Wire numbers match the build sheet. Each length includes 5 mm per end to go through the hole.

Wire	Colour and net	Route	Length	Bends
24	BlackGND R38 → R40	R38 → R40	15mm	Straight
30	BlackGND J18 → E20	J18 → E20	28mm	18mm (90°)
6	BlackFACE1 G22 → G31	G22 → G31	33mm	Straight
18	BlackDIAGB_MID O9 → H15	O9 → H15	43mm	23mm (90°)
12	BlackFACE4 Q22 → N34	Q22 → N34	48mm	35mm (90°)
36	Black9V H34 → B4	H34 → B4	101mm	20mm (90°)
11	BlueTIMING O40 → I37	O40 → I37	28mm	16mm (45°)
5	BlueFACE3 I22 → I30	I22 → I30	30mm	Straight
29	BlueGND R21 → L18	R21 → L18	33mm	20mm (90°)
35	Blue9V N37 → S27	N37 → S27	41mm	23mm (45°)
17	BlueDIAGA_MID G9 → N15	G9 → N15	43mm	23mm (90°)
23	BlueFACE6 R23 → H11	R23 → H11	66mm	28mm (90°), 58mm (90°)
10	GreenTIMING O42 → J41	O42 → J41	25mm	18mm (90°)
28	GreenGND S20 → S14	S20 → S14	25mm	Straight
16	GreenROLL R34 → K34	R34 → K34	28mm	Straight
34	Green9V G40 → G33	G40 → G33	28mm	Straight
4	GreenSIDES_MID G13 → N11	G13 → N11	33mm	23mm (90°)
22	GreenFACE6 S22 → N30	S22 → N30	43mm	25mm (90°)
13	RedFACE5 K22 → M22	K22 → M22	15mm	Straight
1	RedCLOCK J37 → J34	J37 → J34	18mm	Straight
7	RedDISCH L41 → I41	L41 → I41	18mm	Straight
25	RedGND Q37 → P31	Q37 → P31	28mm	20mm (90°)
19	RedCENTER K26 → L11	K26 → L11	51mm	8mm (90°)
31	RedGND C20 → D5	C20 → D5	51mm	43mm (90°)
9	WhiteTIMING P41 → P39	P41 → P39	15mm	Straight
3	WhiteSIDES_R Q10 → P12	Q10 → P12	18mm	10mm (90°)
15	WhiteROLL S35 → S31	S35 → S31	20mm	Straight
33	White9V L38 → H41	L38 → H41	26mm	10mm (45°), 14mm (45°)
27	WhiteGND O30 → Q20	O30 → Q20	40mm	30mm (90°)
21	WhiteCARRY F7 → L34	F7 → L34	99mm	8mm (90°), 76mm (90°)
32	Yellow9V M36 → K37	M36 → K37	18mm	10mm (90°)
8	YellowDISCH N41 → O36	N41 → O36	25mm	18mm (90°)
2	YellowRESET L30 → I34	L30 → I34	38mm	18mm (90°), 28mm (90°)
14	YellowFACE5 J21 → J30	J21 → J30	38mm	8mm (90°), 30mm (90°)
26	YellowGND S37 → H37	S37 → H37	43mm	8mm (90°), 35mm (90°)
20	YellowDIAGB M26 → N7	M26 → N7	61mm	53mm (90°)

About this build

Electronic dice from two chips. A 555 timer clocks a CD4017 decade counter about 140 times a second while you hold the roll button, too fast to follow. Let go and it stops on a face.

The counter resets itself when it reaches six, so it only has six states. Six diodes steer each count onto the right pips of a seven LED die face. The LEDs are wired in pairs that share a resistor, and the centre pip gets its own.

The neat part is the counter's carry output. It's high on five of the six counts, which is exactly when one diagonal pair of pips is lit, so that pair needs no diodes at all.

The parts library has no pushbutton, so the video draws a 6 mm tactile button in the Footprint Editor first and places it like any other part. It runs on 9V.

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