Automated PCB Exposure Timer Kit with Arduino Uno + Relay
Precision UV Exposure Timer for DIY PCBs – Arduino Uno Kit with DS3231 & Relay
Every part needed, pre-tested for compatibility, with an AI build companion trained on this exact project. Shipped from Bengaluru in 3-5 days.
Create consistent, professional-grade photoresist PCB exposures with this Arduino Uno-based timer. Instead of guessing exposure time with a manual UV lamp, you'll build a precise countdown system that drives an 8-LED UV array through a relay, all controlled by a DS3231 real-time clock. The LCD shows the exact seconds remaining, making your exposure process repeatable every time.
What You'll Build
You'll assemble a self-contained exposure unit with a 16x2 LCD display showing countdown in seconds. The tactile buttons let you set exposure time (1-999 seconds), start/stop, and repeat cycles. Once built, you'll use it to expose photoresist copper-clad boards with repeatable results, essential for fine-pitch PCB tracks and double-sided boards.
What You'll Learn
- Interfacing DS3231 RTC to Arduino and using its alarm functions for precise timing
- Controlling a 5V relay module with a transistor driver to switch UV LEDs safely
- Multiplexing tactile buttons for user input and handling debouncing in software
- Integrating an I2C LCD backpack for a compact, reliable display without wiring clutter
Kit Contents
| Component | Quantity |
|---|---|
| Arduino Uno R3 | 1 |
| DS3231 RTC | 1 |
| 5V Relay Module | 1 |
| 16x2 LCD | 1 |
| I2C Backpack | 1 |
| Tactile Button | 3 |
| UV LED 395nm | 8 |
| BC547 Transistor | 2 |
| 100Ω Resistors | 10 |
| 1N4007 Diode | 3 |
| PCB Prototype Board | 2 |
| 9V Battery Snap | 1 |
| Soldering Iron | 1 |
| Solder Wire | 1 |
Why Buy This Kit Instead of Sourcing Parts Separately
| Factor | Sourcing Separately | Compoden Kit |
|---|---|---|
| Compatibility checks | You verify every part | Pre-tested as a system |
| Build support | Forums and scattered tutorials | AI companion trained on this exact project |
| Time to first working build | Days of debugging | Hours, with step-by-step guidance |
| Shipping coordination | Multiple sellers, multiple delays | One shipment from Bengaluru in 3-5 days |
Who This Kit Is For
This kit is designed for engineering students in ECE/EEE branches who need reliable PCB fabrication for mini projects and final-year submissions. It's ideal for participants of hardware hackathons like Smart India Hackathon, where consistent board-making saves hours of rework. Hobbyists who have built Arduino basics will also value the move from manual stopwatches to automated exposure control.
Built and Backed by Compoden
Every Compoden kit ships with an AI build companion trained on this exact project — accessible via a QR code on the box, with WhatsApp and email backup. We've spent 10 years building projects for makers, schools, and institutions across India. If a part fails because of a manufacturing defect, replace it free within 7 days.
What if I get stuck during the build?
Scan the QR code in the box to launch the AI companion, which understands this exact schematic and wiring. You can also message us on WhatsApp for human help.
Can I use this timer for acid etching as well?
The timer controls the UV LEDs; for etching, you would still need a separate tank and chemicals. It's designed specifically for photoresist exposure, but you can adapt the relay output for other timed processes.
Do I need prior soldering experience?
Soldering is required for the UV LED array and connectors, but the kit includes a soldering iron and solder wire. Our AI guide includes soldering tips for beginners.
How accurate is the DS3231 RTC timing?
The DS3231 is accurate to ±2ppm, which means less than 1 second drift per day. Your exposure times will be precise and reproducible.
UV LED array + DS3231 + relay expose photoresist PCBs for timed duration. LCD shows countdown.
What's in this kit
- Arduino Uno R3
- DS3231 RTC
- 5V Relay Module
- 16x2 LCD
- I2C Backpack
- Tactile Button x3
- UV LED 395nm x8
- BC547 Transistor x2
- 100Ω Resistors x10
- 1N4007 Diode x3
- PCB Prototype Board x2
- 9V Battery Snap
- Soldering Iron
- Solder Wire
Choose your assembly option:
- Soldering Kit — 25W soldering iron, 60/40 solder wire, flux, and small perfboard for permanent assembly.
- Breadboard Combo — 800-point full-size breadboard with 65-piece jumper wire pack for solderless prototyping.
Other projects you can build
Shipping Information
- Prepaid Orders: ₹75 for orders up to ₹999, FREE shipping above ₹999
- COD Orders: ₹125 shipping + ₹50 COD fee = ₹175 total
- Delivery Timeline: Dispatch in 1-2 days, delivery in 2-7 days depending on location
Returns & Warranty
- 7-Day Return: Manufacturing defects only (approval required)
- Warranty: 7 days from delivery
- Non-Returnable: Batteries, consumables, cut wires, clearance items