Picapot HT328 Irrigation Controller Kit

The kit includes the PCB and electronic components needed to assemble the Picapot HT328 irrigation controller.
Once assembled, the controller can drive one 12 V DC solenoid valve, pump, relay, or other compatible load with a maximum continuous power consumption of 30 W.

The included ATmega328P microcontroller is supplied with the open-source firmware already installed.

Operating User Manual:
https://raw.githubusercontent.com/picapot/picapot-controller-ht328/main/resources/manual/picapot-328-irrigation-controller-users-manual.pdf

Please note that the 3D-printed controller case and the CR2032 battery are NOT included in the kit.
3D-printing files, detailed assembly instructions, setup guidance, and open-source firmware are available at https://www.picapot.com.

SMART IRRIGATION FUNCTIONS

• Four watering modes: Fixed Time, Auto Dusk2Dawn, Advanced Dusk2Dawn, and Fixed Interval, allowing watering at fixed times, at regular intervals, or automatically relative to sunrise and sunset
• Optional seasonal adjustment of watering duration and frequency based on day length
• Optional soil-moisture-based watering skips with an external Picapot PS100 sensor
• Frost protection
• Increase watering duration during hot weather

RTC FEATURES

• DS1307 real-time clock (RTC) with CR2032 battery backup
• Battery-level display
• Automatic leap-year handling
• Clock calibration
• Optional automatic daylight saving (EU/US/AU/NZ)
• Fractional timezone settings

OTHER FEATURES

• Adjustable watering duration from 15 seconds to 1 hour
• Manual watering with an adjustable timer
• History of the six most recent automatic, manual, and skipped watering events, with codes identifying why watering was skipped
• Daily minimum and maximum temperature readings, plus soil-moisture readings when using a PS100
• EEPROM settings backup and automatic recovery
• Automatic fallback to the internal temperature sensor if the selected external sensor becomes unavailable, with automatic detection of a reconnected or replacement external sensor

TECHNICAL SPECIFICATIONS

• Supply voltage: 12 V DC
• Maximum continuous load power: 30 W
• Recommended power-source capacity: at least 0.25 A for the controller and sensor, plus the connected load current
• Compatible external sensors: DS18B20 or Picapot PS100 temperature and soil-moisture sensor
• Display: 2.42-inch 128×64 SPI OLED
• RTC backup battery: CR2032, not included
• PCB dimensions: 96 × 72 × 1.6 mm
• Final product dimensions: 120×81×22 mm
• Reverse-polarity protection: yes
• Valve-flyback protection: yes
• Open-source hardware and firmware

KIT CONTENTS

• PCB ×1
• ATmega328P-PU (original Microchip), preprogrammed with firmware ×1 (U1)
• DS1307 (original Maxim) ×1 (U2)
• IRLB3813PBF TO-220 N-channel MOSFET (original Infineon) ×1 (Q1)
• DS18B20 (Maxim or UMW) ×1 (U3)
• LM7805 ×1 (U4)
• 16 MHz crystal, 18 pF load capacitance ×1 (X1)
• 32.768 kHz crystal, 12.5 pF load capacitance, 5 ppm tolerance ×1 (X2)
• Red 3 mm LED ×1 (LED1)
• 6 mm LED spacer ×1
• 2 MΩ, 1/8 W resistor ×1 (R1)
• 10 kΩ, 1/8 W resistors ×5 (R2, R4, R5, R7, R8)
• 2.2 kΩ, 1/8 W resistor ×1 (R6)
• 300 Ω, 1/8 W resistor ×1 (R3)
• 100 Ω, 1/8 W resistor ×1 (R9)
• 100 nF ceramic capacitors ×7 (C1, C2, C5, C6, C7, C8, C9)
• 22 pF ceramic capacitors ×2 (C3, C4)
• 40 V, 5 A Schottky diodes ×2 (D1, D2)
• Fuse clips for a 5×20 mm fuse, 4.8 mm pin pitch ×2 (F1, F2)
• 3.15 A, 5×20 mm fuse (original OMEGA) ×1
• SPST tactile switches, 12×12×11 mm ×3 (SW1, SW2, SW3)
• CR2032 battery holder ×1 (BAT1); the CR2032 battery is not included for shipping reasons
• 2.42-inch 128×64 SPI OLED display ×1 (DISP1)
• Display spacer ×1
• Seven-position terminal block, 5 mm pitch ×1 (P1)
• 2×3-pin male header ×1 (P2)
• 19×14 mm TO-220 MOSFET insulating pad ×1
• M3 × 5 mm bolts ×2
• M3 nuts ×2
• 68×20 mm adhesive label ×1

EQUIVALENT COMPONENTS

Depending on availability, the following components may be replaced with equivalent parts:
• Infineon IRLB3813PBF → Infineon IRLB8743
• Maxim / Analog Devices DS18B20 → UMW DS18B20


IMPORTANT INFORMATION

• This is a DIY electronics kit, not a finished controller. The buyer must assemble and solder the through-hole components, which are mounted on both sides of the PCB. Soldering skills and electronic assembly experience are required.
• The finished controller is not waterproof and must be installed in a suitable waterproof enclosure when used outdoors or near water.
• Use a 12 V DC power source and a compatible 12 V DC load. Maximum continuous load power is 30 W. Account for the controller’s own consumption and the load’s starting current when selecting the power supply.
• For higher-power loads, use an appropriately rated external relay.
• Powering the controller from its 12 V input is recommended, including during programming. USB-derived power through the ISP port at approximately 4.5 V places the DS1307 real-time clock IC at the lower limit of its specified supply range and may cause instability or unexpected resets.
• Users must assess suitability and choose irrigation settings for their plants, soil, water supply, installation, and environmental conditions.

Manufacturer(s):

Fabrizio Ranieri trading as Picapot
Gozo - Malta
https://www.picapot.com/contact

Product safety:

Contains small parts. Keep away from children and pets.

For adult use only. This product is not a toy. Assembly and soldering skills are required.

Use only a compatible 12 V load. Do not exceed the maximum load power of 30 W or the total fuse-limited system current of 3 A.

The controller is not waterproof. Install it in a suitable waterproof enclosure if used outdoors, near water, or where condensation may occur.

This controller is not designed, intended, or authorized for use in systems intended to support or sustain human or animal life.

Dispose of the PCB, electronic components, fuse, and CR2032 battery through the appropriate collection channels. Do not dispose of them with household waste.