Sprinkler Controller 2.3

 

A custom designed board capable of controlling AC or DC sprinkler valves just by replacing hand full of parts during assembly.
The board was designed to be flexible of using either readily available modules or fully assembling it using individual components. Most of the board uses surface mounted components to make it  compact thus its not for the beginner that never soldered SMD components.
The 2 modules that can be used are clock/eeprom  and ENC28J60 Ethernet module.

For DC version a minimal of 6.5V and no more than 24V needs to be applied as the board logic uses 5 volts then it gets regulated down to 3.3v for the processor. When providing less then 24V an optional DC booster board plugs into P1 to boost it to 24V in order to energize relays.

There are some components that do need to be placed on the PCB like main processor, output logic and final driver transistors, SD card socket, some passive components like resistors and capacitors. Optional USB and USB to serial chip (CH340) , numerous connectors and power supply.

As the board is based on Ray's Hobby,  Open Sprinkler, few 2.x versions of the hardware selected  components had been selected and and included on this board. Port expansion connector had been changed to 10 pins, otherwise it has all the signals and standard port expansion modules can be connected to it adding extra ports to it. Port expansion connector also had been changed to 24 pins adding extra unused signals and adding power pins to it.

Ray's Open Sprinkler firmware can thus be uploaded to the process and turn the board into functioning web enabled sprinkler controller provided ethernet module is installed.  Latest version of the firmware requires larger processor memory so when assembling the larger ATmega1284 processor needs to be soldered onto the board thus some planning needs to be taken into consideration.

Another unique feature of the board is that the main driver logic is the same between AC and DC versions and only the drive transistors are of difference and in DC version DC voltage booster is required to drive the valve body unless larger voltage power source is connected to it the board. An optional DC booster board plugs into P1 port  which has MC34063 switching regulator configured in boost mode with control logic to turn the circuit on and turn on the output power to the valves. The booster simply plugs into the main board






Documents

Main Schematic
Booster schematic        <link to project files>
PCB files
Booster files
3D view
ATmega644 / 1284
DS1307
DS3231
CH340
74hc595
24AA02
PCF8574
MC34063