Chat

How can I help you?

Explain project

Write a project description

Find schematic issues

Files

Schematic

Layout

Preview

U5 LCD

Manufacturer Part Number

NHD-C0216CIZ-FSW-FBW-3V3

R13

Resistance

220kΩ

R19

Resistance

10kΩ

R17

Resistance

10kΩ

Resistance

10kΩ

Resistance

10kΩ

Resistance

1kΩ

R16

Resistance

100kΩ

Resistance

470Ω

Resistance

10kΩ

Resistance

10Ω

R10

Resistance

4.7kΩ

R18

Resistance

10kΩ

R12

Resistance

220kΩ

Resistance

10kΩ

R15

Resistance

100Ω

Resistance

10kΩ

R11

Resistance

4.7kΩ

Resistance

10kΩ

Button ON_OFF

Manufacturer Part Number

RV-3028-C7 32.768KHZ 1PPM-TA-QC

LED1

Button Plus

Button Minus

Button Col

C12

Capacitance

2.2uF

Capacitance

1uF

C14

Capacitance

100nF

C15

Capacitance

100nF

C18

Capacitance

10nF

Capacitance

100nF

C16

Capacitance

100nF

C13

Capacitance

10uF

Capacitance

100nF

Capacitance

10uF

Capacitance

1uF

C17

Capacitance

10nF

Capacitance

100nF

Capacitance

100nF

C11

Capacitance

10nF

Capacitance

10nF

C10

Capacitance

10nF

J1 AC Mains In

J6-AC Mains Out

PS1

MOV1

Inductance

4.7 µH

Capacitance

1 F

RT1

K1-Relay

U5-Light Sensor

J2 -CR2032 Holder

Relay / Contactor Options Comparison

Load Requirement

External load: Spa Electric LV25-12 swimming pool LED light system
Switched load: 240 VAC, 25 W
Steady-state current estimate: 25 W / 240 VAC = 0.104 A RMS
Requirement: switch active and neutral using 2-pole mains-rated contacts; do not switch PE.

Shortlist

Table

Option	Type	Coil	Contact Form / Rating	Approx. Low-Qty Price	Procurement Notes	Design Impact
Finder 22.32.0.012.4320	DIN modular contactor	12 VAC/DC	2 NO, 25 A, 440 VAC class	~A$115 inc GST each from RS AU	Good Australian low-volume procurement, recognizable industrial part	Requires 12 V coil drive, not current 5 V rail
Finder 22.32.0.012.4520	DIN modular contactor	12 VDC	1 NO + 1 NC, 25 A	~A$105 inc GST each from RS AU	Easy RS AU procurement, but contact arrangement is not ideal for 2-pole switching because one pole is NC	Not recommended for active+neutral simultaneous NO switching
Phoenix Contact 2961299	DIN rail relay module	12 VDC	DPDT, 10 A	~A$14 inc GST each from RS AU	Very low cost and easy AU procurement; check exact approvals/load category	Requires 12 V coil drive; relay module/socket style
Jaycar / Electus SY4065	Plug-in relay	12 VDC	DPDT, 10 A at 240 VAC	~A$8.05 each at qty 10 from Jaycar	Cheapest local source; good for prototypes, weaker compliance/professional procurement story	Requires relay cradle/socket and 12 V coil drive
Omron G6B-2214P-US DC12	PCB power relay	12 VDC	DPST-NO, 5 A, AC-rated	~US$9.81 from DigiKey	Reputable relay, good stock; PCB-mounted mains requires careful compliance/layout	Requires 12 V coil drive and brings mains onto PCB
Panasonic DSP2A-L2-DC5V	PCB latching relay	5 V dual coil	DPST-NO, 5 A, 250 VAC	~US$8.77 from Mouser	Matches existing dual-coil 5 V architecture; reputable brand	Brings mains contacts onto PCB; less preferred than external contactor stage
Same Sky PRL1-5V-DC-2A	PCB latching relay	5 V dual coil	DPST-NO, 16 A, 277 VAC listed	~US$4.90 from Mouser	Cheapest 5 V latching option; good stock in search result	Needs deeper approval/datasheet review before product use; PCB mains separation required
Omron G7L-2A-T DC12	Power relay	12 VDC	DPST-NO, 25 A, 277 VAC	element14/DigiKey class, ~US$20+ or AU supplier-dependent	Very robust contact margin	Requires 12 V coil drive; larger relay, may be overkill

Recommendation

For product-oriented low-volume batches of ~10 units, prefer an external DIN-rail/contact-module approach over PCB-mounted mains contacts.

User Decision

Selected relay module: Phoenix Contact 2961299 DIN rail relay module, 12 VDC coil, DPDT / 10 A class, sourced via RS Australia class distribution. This is the project relay baseline unless later superseded by compliance review.

Recommended baseline

Finder 22.32.0.012.4320 or equivalent 2-pole, 2-NO modular contactor with 12 VAC/DC coil.

Rationale:

Strongest compliance/procurement story among the researched options.
True 2-pole normally-open contactor behavior for active + neutral switching.
Large contact margin relative to 0.104 A steady-state load.
Available from RS Australia in low quantities.

Tradeoff:

It is expensive at roughly A$115 each and requires a 12 V coil supply/driver, so the current 5 V relay-driver section should be revised if this is selected.

Selected cost-optimized pilot / low-volume option

Phoenix Contact 2961299 DIN rail relay module, if its approvals and exact contact load category are acceptable after datasheet review.

Rationale:

Much cheaper at roughly A$14 each.
Easy low-volume AU procurement.
Contact rating appears far above the 25 W load.

Tradeoff:

Needs exact datasheet/compliance review before product release.
Still requires 12 V coil drive.

Not recommended as final product default

Jaycar/Electus plug-in relays are attractive for quick prototypes, but are weaker for a compliance-reviewed commercial spa/pool-adjacent product. PCB latching relays are cheap and can match the existing 5 V architecture, but they put mains contacts on or near the control PCB and increase layout/compliance burden.

Required Schematic Update if Recommended Contactor is Chosen

If the Finder/Phoenix 12 V coil path is selected:

Replace the current +5V relay coil output assumption with a 12 V coil supply or external 12 V coil input.
Update relay driver MOSFET voltage/current ratings and flyback clamp.
Update connectors and labels to RELAY_COIL_12V_SET/RESET or CONTACTOR_COIL_12V.
Re-run power budget for coil current and sealed-enclosure thermal rise.

Decision Status

Phoenix Contact 2961299 selected. Remaining decision: provide the 12 V relay coil power either from an external 12 V SELV input or by revising the controller PSU architecture to add a 12 V rail.

Load Requirement
Shortlist
Recommendation
User Decision
Recommended baseline
Selected cost-optimized pilot / low-volume option
Not recommended as final product default
Required Schematic Update if Recommended Contactor is Chosen
Decision Status