If any of the initiatives you create are designed for portability or distant monitoring use, it normally requires using inventive energy sources. Solar energy can typically be a helpful answer for powering such units. On this tutorial, we’ll focus on easy methods to choose the correct photo voltaic panel based mostly in your energy necessities, notably for initiatives utilizing Arduino. We may also contact on energy administration and cost controllers.
Parts wanted for this undertaking:
*Precise values will rely in your undertaking’s energy necessities.
Choosing the Proper Arduino for Your Venture
On this train, we’ll evaluate the three totally different Arduino boards to see which one most closely fits your wants. Listed below are the assorted attributes used to find out the most effective suited to our instance.
The Arduino UNO shall be our benchmark platform. Let’s begin by itemizing the attributes after which evaluate the three boards.
Arduino UNO
- Microcontroller ATmega328P, 8-bit AVR household microcontroller
- Working voltage: 5V DC
- Enter voltage 7 – 12V DC
- Analog inputs: 6
- Digital I/O: 14, 6 PWM
- SRAM: 2KB
- EEPROM: 1KB
- Flash 32Ok
- Clock Velocity: 16 Mhz
- USB connection
- Energy (idle) 50 mA
- Measurement: 2.7″ X 2.1″
Arduino NANO
- Microcontroller ATmega328P, Eight bit AVR household microcontroller
- Working voltage: 5V DC
- Enter voltage 7-12V DC
- Analog inputs: 8
- Digital I/O: 22, 6 PWM
- SRAM: 2KB
- EEPROM: 1KB
- Flash 32Ok
- Clock Velocity: 16 Mhz
- USB Connection
- Energy (idle) 19 mA
- Measurement: 1.7″ X .73″
Arduino Professional-Mini 3.Three V
- Microcontroller ATmega328P, Eight bit AVR household microcontroller
- Working voltage: 3.3V DC
- Enter voltage 3.3-12V DC
- Analog inputs: 6
- Digital I/O: 14, 6 PWM
- SRAM: 2KB
- EEPROM: 1KB
- Flash 32Ok
- Clock pace: Eight Mhz
- Energy (idle) 4.7 mA
- Measurement: .7″ X 1.3″
All three boards incorporate the identical microcontroller. They’ve almost the identical variety of analog ports, digital ports, PWM ports, and reminiscence configuration. Probably the most important variation is within the clock pace, energy necessities, and the bodily measurement of the boards.
The first goal in designing a tool working in solar energy can be to cut back energy consumption. With that goal and the attributes given above, we now evaluate and select between Arduino Uno, Nano, and Professional Mini.
An Arduino Uno attracts roughly 50 mA over 2 1/2 instances what a Nano requires at 19 mA. The Professional Mini with 4.7 mA brings 11 instances lower than an UNO. And evaluating the three, Professional-Mini is significantly smaller and cheaper.
Clock Velocity of the Professional-Mini
Other than the facility consumption, the massive distinction is the clock pace of the Professional-Mini. This slower clock pace accounts for probably the most important lower in energy wanted for the Professional-Mini. Relying in your software, this will likely or could not adversely have an effect on the circuit.
One other distinction is that the Professional-Mini doesn’t incorporate a USB host controller. This omission requires you to make use of an FTDI controller to program the Professional-Mini, probably including some price to your undertaking. Eliminating the USB controller energy consumption is lowered in addition to general value and measurement.
In your design, you need to use Nano should you want the additional clock pace, or probably want to connect 5-V peripherals. There’s additionally a 5-volt Arduino Professional-Mini out there that runs a 16 Mhz clock. Should you determine to make use of a 5V Arduino, merely add a lift converter after the three.3V provide (Amazon Mannequin XL6009 DC to DC converter). However for this train, we’ll use the 3.3-V Professional-Mini.
Cost Reservoir (Battery Supply)
Many rechargeable batteries can be found to run the Professional-Mini. For this instance, we’ll use a lithium-ion battery that gives a 3.7-V supply from a single cell.
When deciding to make use of a lithium-ion battery, security elements have to be thought-about. Take observe that lithium-ion batteries, if misused or mishandled, can catch fireplace or blow up. It’s essential to take additional precautions contemplating the battery has a excessive quantity of vitality and unstable chemical content material.
To keep away from these potential issues, lithium battery cost controllers have been designed to soundly management the charging and discharging charges.
Battery Cost and Safety
TP4056 Battery Cost and Safety module addresses the next considerations round charging and sustaining lithium-ion batteries:
- Manages fixed present to fixed voltage charging of a related lithium battery
- Over-discharge safety – prevents the battery from discharging under 2.4V.
- Overcharge safety – safely prices the battery to 4.2V.
- Overcurrent and short-circuit safety – minimize the output from the battery if the discharge price exceeds 3A or within the occasion of a short-circuit.
- Trickle cost (battery reconditioning) – the voltage stage of the related battery is lower than 2.9V. Additionally, the module will use a trickle cost present of 130mA till the battery voltage reaches 2.9V. At that time, the cost present shall be linearly elevated to the configured cost present.
- Mushy-start safety – limits in rush present.
This configuration prices the battery in addition to provide energy to the circuit when the photo voltaic cell is producing vitality. At evening, the cost circuit disconnects, and the battery is used as the facility supply for the circuit.
The 03962A cost controller additionally permits charging from a 5-V cellphone charger (USB mini cable). The MCP 1700 successfully regulates the voltage to the required 3.Three V for the Professional-Mini. Two capacitors are used to eradicate noise and easy out the output voltage. Discover that the 100 uF capacitor has a polarity.
Lithium-Ion Batteries could be related in parallel if each batteries are similar. Its working temperature is 10°C to 55°C whereas charging temperature is 5°C to 45°C.
Choosing the Photo voltaic Cell and Lithium battery
Within the subsequent article, we’ll cowl methods to include energy saving into your code, which is able to assist cut back the present drawn from the battery.
Taking into consideration the facility necessities of your accomplished circuit, you’ll be able to start to design the facility circuit.
We start with the belief that your system shall be used remotely, working 24 hours a day, seven days every week. You must use the day with the least daylight in 24 hours and it’s December 21. And that will help you decide the quantity of sunshine in your space, it’s possible you’ll check with this web site: http://latlong.net.
After calculating your latitude, it’s possible you’ll refer here to see what number of hours of daylight you’ll be able to obtain in December. In my case, the chart exhibits that in December solstice, the solar shines 10 hours a day in San Antonio.
The subsequent calculation that you could verify here determines the speed by which you’ll be able to count on the solar shall be shining, bearing in mind overcast days. For my location, I can count on 67% of the time on December 21, receiving 10 hours of daylight.
Calculating Photo voltaic Panel and Battery Sizes
Now, we’ll calculate the dimensions of the photo voltaic panel and battery to energy my circuit that attracts 23 mA. Utilizing the odds calculated above, this implies I’ll have 6.7 hours of daylight for charging time on the shortest day of the 12 months (67% of 10 Hours = 6.7 hours).
Given the calculation above, my circuit will draw 522 mAH/day (23 mA x 24 Hours = 522 mAH/day). If we’ve 6.7 hours of daylight, then the facility provide should ship 82 mAH (552 mAH / 6.7 Hours of daylight = 82 mAH). To be on the secure facet and to account for 2 closely overcast days, we must be double the speed (82 mAH X 2 = 164 mAH).
Given these, we should select a photo voltaic panel able to no less than 5-7 V @ 164 mAH, and a Lithium battery rated at 1044 mAH. To be conservative, my photo voltaic panel is rated at 6 V @ 500 mAH; the lithium-ion battery is rated at 2000 mAH.
