Hello All,
i have taken on a project for my daughter which entails flashing LEDs and a buzzer. i have proto-typed it on a breadboard using an ARDUINO UNO . The program is fine and does what we want it to do.
This project will be used outside continuously so I will want to use a 12V Battery.
I have attached a schematic of the parts that i have researched so far.
I will have 9 12V LED assemblies in this project. The schematic shows just 1 for clarity.
My queries are as follows..
1/ is the schematic o.k.?
2/ I need to be able to recharge the battery without taking it out of its enclosure. How do I facilitate this?
3/ I will also need to create 5 volts from the 12 v battery for the ARDUINO UNO,( this is another black hole for me.)
how can this be achieved?
I have read that a 12V to 5V car phone charger will do.
I have also read that it might be better to use a voltage regulator.
When the battery begins to drain will it create any dangerous issues?
How do i build protection into the circuit?
And finally... would it be wise to put a battery read out on the control panel or is it a complete waste of time?
I assume the LED assembly has current limit for the LED.
I would use a SMPS similar to this, but you might want to think about a lower voltage battery.
The LED assemblies are car trailer units, they require 12V @).04mA. I hooked up a power supply to these and they drew 0.04 amps. that unit looks the business. i just might go with that for the 5 volts .
i would prefer to bring the panel in to the house when the battery runs down to recharge it with 220 v or 110 v depending on where my daughter brings the unit.
Apart from the buzzer , 9 LED assemblies and the ARDUINO UNO I will use 2 to 3 switches to trigger various code , each switch will have a LED diode as a indicator. The LED units will only be triggered by the code for 2 seconds max. per cycle with each cycle running a time between 1 to 20 seconds ( adjustable by a pot.)
sorry no , i hadn't factored in a pro mini. is that a better option to the ARDUINO UNO?
I have also read that it might be better to use a voltage regulator.
Linear Voltage regulator - No
SMPS Buck Converter - Yes
So it's better to use SMPS
mechup:
2/ I need to be able to recharge the battery without taking it out of its enclosure. How do I facilitate this?
3/ I will also need to create 5 volts from the 12 v battery for the ARDUINO UNO,( this is another black hole for me.)
how can this be achieved?
When the battery begins to drain will it create any dangerous issues?
How do i build protection into the circuit?
And finally... would it be wise to put a battery read out on the control panel or is it a complete waste of time?
You can solve all these issues by using a powerbank instead of that 12V battery.
-You can charge it without taking it out of the enclosure
-It outputs 5V, so arduino has no problem taking power from it.
-It won't create any dangerous issues when discharging
-It has built in protection circuit
-Most models have battery charge status indicators built in.
You just have to use a Boost converter to power the LEDs, you don;t have to worry about your battery issues if you use a powerbank instead of 12V battery.
Powerbank is basically a battery pack used to charge your cellphones when you are on the move and can't find a AC wall socket nearby to charge your phone.
It's got a Micro USB charging port - You can charge this using your phone charger
It's got a USB out port - you can power your arduino with it
It's got 4 LEDs showing battery remaining charge status.
The original scematic looks fine to connect the Arduino Uno directly to 12V on the barell connector. The only reason why you wouldn't would be if there were other devices powered from 5V such as an LCD display.
As for charging I expect that any small charger or battery-tender could be connected directly to the battery. Don't put it downstream of the battery isolator as that may attempt to power your circuit without the battery connected.
Noobian:
Powerbank is basically a battery pack used to charge your cellphones when you are on the move and can't find a AC wall socket nearby to charge your phone.
And most of them cut out when the load is little (they are designed to recharge phones),
which can be a problem with just an Arduino which only needs a few tens of mA.
mechup:
I will be using single red LEDS , 1 per switch ( x 3)
as an indicator. these will be powered from the ARDUINO UNO
Red LEDs need only 2.4 volts, they can be powered from the 3.3v pin as well.
Also you wont be needing a boost converter
MarkT:
And most of them cut out when the load is little (they are designed to recharge phones),
which can be a problem with just an Arduino which only needs a few tens of mA.
True, but I have 2 different types of powerbanks, both of them powered a 20mA LED without any cutoff.
