Article

Sand Clock

A real eye-catcher

This nifty gadget built around an Arduino Uno uses some servos and a pantograph mechanism to write the time in a sand bed. After a configurable time interval the sand is smoothed out by a pair of vibration motors and the cycle starts over again. Along with the automatic time mode, the clock software has a command mode which allows you to control the pen using simple commands.

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Materials

Sand Clock

Assembly Manual

PCB PDF

Software, CAD data & Manual

Gerber file

CAM/CAD data for the PCB referred to in this article is available as a Gerber file. Elektor GREEN and GOLD members can exclusively download these files for free as part of their membership. Gerber files allow a PCB to be produced on an appropriate device available locally, or through an online PCB manufacturing service.

Elektor recommends the Elektor PCB Service service from its business partner Eurocircuits or AISLER as the best services for its own prototypes and volume production.

TIP: your first PCB at AISLER is free up to €30 with using the coupon code ELCCBB at checkout.

The use of our Gerber files is provided under a modified Creative Commons license. Creative Commons offers authors, scientists, educators and other creatives the freedom to handle their copyright in a more free way without losing their ownership.

PCB

Download Gerber file: 160065-1_sand_clock_gerber.zip

Component list

Component List
Resistors
R1,R2,R3 = 220Ω, SMD 0805
R4 = 1.8kΩ, SMD 0805
R5–R9 = 4.7kΩ, SMD 0805
R10 = 100kΩ, SMD 0805

Capacitors
C1–C4 = 100nF, SMD 0805 MLCC
C5 = 10µF 10V, SMD 1206 MLCC
C6 = 22µF 16V

Semiconductors
D1,D2,D3 = S2J-E3
T1 = BCX56
IC1 = SIP3 5V/1A DC/DC converter (Würth Elektronik # 173 010 578)
IC2 = PCF2129A

Miscellaneous
K1 = set of SIL pinheaders, 0.1’’ pitch (1 pc. 10-pin, 2 pc. 8-pin, 1 pc. 6-pin)
SERVO_Z,SERVO_L,SERVO_R = 3-ppin right-angled pinheader, 0.1’’ pitch
B1 = CR2032 button cell with holder
Arduino UNO R3 or equivalent

Mechanical parts
6 pcs. bolt, M2x10, Pozidrive/Phillips
6 pcs. bolt, M2.5x8, zinc-plated steel, Pozidrive DIN 7985A
6 pcs. bolt, M2.5x12, zinc-plated steel, Pozidrive DIN 7985A
2 pcs. bolt, M3x6, zinc-plated steel, Pozidrive DIN 7985A
2 pcs. bolt, M3x8, zinc-plated steel, Pozidrive DIN 7985A
15 pcs. bolt, M3x10, zinc-plated steel, Pozidrive DIN 7985A
1 pc. bolt M4x30 plastic, Phillips (sharpen end with pencil sharpener)
6 pcs. nut, M2, zinc-plated steel, DIN 934
7 pcs. nut, M3, steel, DIN 934
3 pcs. locking nut, M3, zinc-plated steel, DIN 985
1 pc. nut, M4, polyamide
2 pcs. washer, M3, zinc-plated steel, DIN 125A
4 pcs. washer, M3, plastic, DIN 125A
4 pcs. standoff, 3mm high, polyamide, for M3
4 pcs. spacer, 25mm, M/F M3, nickel-plated brass (min. 33mm total height, e.g. TME TFM-M3X25/DR213)
2 pcs. cable clip, polyamide, Panduit type CCS25-S10-C
4 pcs. self-adhesive rubber foot
3 pcs. micro servo, Tower Pro MG90S of MG90 with metal cogs
2 pcs. vibration motor, round, 6mm diam., type VM6ZK273 (JPR Electronics # 450-007)
Extruded (XT) PMMA, 3mm, clear, laser-cut
Fine-grain white sand (see text)
Nourishment coloring additive (optional)

A DIY kit including all parts and the SMD-preassembled shield is available through the Elektor Store.