Automatic water motor controller is the first project being created here using ATMEGA328 as the main controller (provision for manual bypass of the automatic control is also provided). The motor controller will sense the water levels in both the reservoir (sumps) and overhead water tank and take actions accordingly.
All the requirements of the project are listed here:
- Sense 10% water level in tank - Automatic water motor controller board will turn on Motor if not running. Before turning on circuit will check for water level in the sump. If it is above a predefined level motor will be powered.
- Sense 99% water level in tank - Motor controller will turn off Motor if running.99% or 95% depending on the size/shape of the tank and force of the water flowing into the tank.
- Sense 90% water level in tank - Here Hysteresis of 10% is given. If water level is more than 90%, the motor controller will not turn on the motor though user insists. An indication will be given to user so that user will not confuse with automatic water motor controller not working.
- Sense Flow - This is to sense whether the water is flowing into the tank (To tackle case of no water only motor running/Pressure lost etc). A sensor will be placed in front of the mouth of the pie where the water will fall into the pipe. the signal might be noisy with several makes and breaks, hence a 3-5 second watch dog timer kind of thing will be kept in software to address the issue.
- Sense motor temperature - In rarest of the case, if the Automatic water motor controller senses that the temperature of the motor is above some threshold, the motor will be turned off.
- Sense Keypad input & Sense RTC- user can enter time in minutes for the motor to run. If tanks gets filled before the programmed duration, motor will be turned off, else motor will be kept running for predefined duration. there is also a option for programming automatic turn on and turn off every day for predefined duration. ATMEGA328 and RTC interface will make sure that timing information will be kept intact even during power outages. ATMEGA328 and RTC interface will be backed up by single lithium cell battery. Currently assumed is CR2032 coin cell - rechargeable battery.
- Sense Water level high/low in Sump - This is to make sure that water level in the sump is above a predefined level so that water motor controller can be turned on safely. This helps in cases where the motor foot valve needs some water always at it and emptying the water maximum possible is like temporary suicide. The vacuum built inside will be lost and somebody has to fill in the water in the water pipe going to the tank mostly after climbing to the terrace and jumping inside the tank. Another hurdle is that water motor will run empty for a few seconds before the water flow sensor signals the MCU regarding the same. To avoid this, a predefined water level threshold will be monitored and motor will be instantly turned off if the water level is less than the pre defined threshold. User will be indicated about the same. Water level high indicates safely motor can be turned on and water level low indicates strictly water motor has to be turned off
- A single piezo electric buzzer is planned to use for following audible indications:Indicating no Water flow –Indicating Excess motor temp –Indicating motor running –Indicating tank is full –For critical information buzzer will be made to sound at high frequency pulses and for normal indications a beep every 5 -10 seconds will be produced.
- Following are the visual indications
for the user:
Indicate No water flow –Indicate tank full –wIndicate No water in sump –Indicate tank is full (>90%)–For all the indications, a simple back-lit banner is planned to use 4 to 5 LEDs in series for each indications/banners.
- Safety precautions - Last but not the least - All safety precautions should be taken care not limited to water proof, dust proof and more importantly shock proof.
Hardware At a Glance
Tentatively two boards are planned.
First board will constitute ATMEGA328 and RTC interface, ATMEGA328 and Driver IC ULN2003A interface, ATMEGA328 and RS232 driver IC, ATMEGA328 and simple Keypad interface. Keypad type and all has not been finalized yet it can be a 4x1 or 4x4. LEDs will be driven by ULN2003A IC as it can sink huge currents and takes less space when compared with discrete transistor solution for 5 indications. ULN2003A is also considered for the reason that a rotating banner is also planned, Motor of which will be driven by ULN2003A and ATMETGA328 interface again.
Second board will be a ATMEGA328 and motor interface. Board will have to play with 230 V AC 50 Hz signal and hence TRIAC, TRIAC driver IC, an opto-coupler to isolate controller board from 230 V section. A few other discrete for TRIAC housekeeping.
So, two PCBs.
