Hey all,
I’m hoping to control and power all these components using my Arduino ELEGOO Mega 2560 & 9V battery. Do you think it’ll work?
Note: I’ll be using 3 of these micro servo motors
Thanks!
Tina
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Hi Teena
What sort of a 9V battery are you contemplating. The data sheet for that LED strip says colour white at full brightness will need about 5A at 5V. A bit more than the 9V batteries I have come across lately.
Then you have to add in all the other bits. The little motors at 4.8V no load 100mA, stall 550mA and that is each.
You should maybe add up what you need to drive all these things then look for a suitable supply.
Cheers Bob
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The Arduino ELEGOO Mega 2560 is a very capable micro, I have used one myself.
If the 9V battery, you mention is the standard type, it will not work. These batteries only provide up to 200mA and tend to die pretty quickly.
Given what you have listed and what you still need, your power supply should be capable of at least 5A. The LED strip takes a lot of power (as Robert has mentioned). While building and testing an external supply would be best. Batteries would require recharging or replacing often in the development stage.
The other devices you have listed can be connected to the Mega GPIO pins, but not the stepper motor.
The stepper motor requires a driver board as mentioned in the Core Electronics web page.
This board allows control of many devices and would be good for development, but costs a lot.
This board is cheaper and should work but only does one motor.
An interesting thing about stepper motors is they consume current all the time while operating, it is how they maintain the position they are moved to. They also get hot while doing this.
Careful selection of voltage supply to the motor and where is comes from is necessary and should be chosen based on the motor.
WARNING: the 5V pin on the Mega cannot be used as a 5V power supply. This 5V comes from a regulator on the board and is only capable of about 50mA. You can damage the regulator if you try to get too much current out of it.
Suggest looking at getting an external supply capable of at least 2A. Until you get it all working, then look at a battery source. I know the LED strip says 5.5A but that is with all lights on and white, ie its the maximum, it you don’t drive all lights at the same time it will work with much less current.
Bench Power supplies can be expensive though. I use the following with a 12V 2A plug pack as a bench supply for testing my project, just have to be careful it is set to the right voltage.
WARNING: the device you have listed can be easily damaged if connected to the wrong voltage.
Hope this makes sense, the electronics world is full of pit falls, I have found many, LOL
Cheers
Jim
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Hi Teena
Just an add on to James’ reply.
The power supply module he linked
is a STEP DOWN converter. That means the input voltage has to always be at least about 2V higher than the required output voltage. Sometimes the wording implies that you can input any voltage within a range and output any voltage within a range. Can be misleading. Sometimes you can but very rarely. In this case not.
Cheers Bob
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Thank you Bob for your help! 
Say if I exclude the LED strip, would I still be able to run all my other components for at least 20-30 mins?
This is the 9V battery I have: 9V Battery Australia
To get more power, would you recommend me go for a lithium ion battery? https://core-electronics.com.au/search/?q=lithium+ion
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Thank you James! This is awesome!
I’m going to exclude the lights, as they take up lots of power.
Currently my 3 motors & 1 stepper are connected to my laptop and they’re all working (woohoo!)
I had 2 q’s:
- Instead of a 9V battery, would you recommend using Lithium Ion battery instead? https://core-electronics.com.au/search/?q=lithium+ion. Can Lithium ion power all of my components? What Lithium ion battery would you recommend?
- I’m creating a robot that will be placed outdoors, which is why I’m hoping to not connect it to a bench. Should I use a Lithium Ion battery instead?
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Wow! I never knew about that!
Thank you Rob!
If I were to connect a lithium ion battery to my Arduino mega, do I need a step down converter too?
I’m scared my Arduino mega will blow up 
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The 9V Battery is not powerful enough to run your setup. It is also too high a voltage for the servos, IR detector and stepper. The web page for these devices say 5V. I accidently connected a servo (like what you have linked) to 8V and it stopped working after a few runs.
The LiPo’s will work but you need a voltage regulator to step it up to 5V and a device to charge the LiPo.The voltage on a LiPo varies over its charge cycle. Discharged = 3.2V, Charged = 4.2V.
This device will charge the LiPo and you would need another device to step the voltage up. It has a USB-C connector which has become the standard.
This device is expensive but includes charging and voltage step up. It will provide up to 1A which might be enough depending on what you are doing with the servos and stepper motor. If these devices stall (ie something stops their movement) they can draw up to 0.5A or more, each.
There are other power options too. NiNH cells is one. No matter what you choose you will need a voltage regulator to keep the volts at 5V over the life of the battery. And if you choose rechargeable batteries you will need a way of charging them.
I have provided only a few options to give you an idea of what you need to consider in your design.
Regards
Jim
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A single lithium ion cell is 3.7v - that is not enough to power a mega. You could use a converter to increase the voltage, but a better solution is to use multiple cells to get the required voltage. Two cells will give 7.2v while 3 cells will give 11.1v. Your mega requires either exactly 5v or anything from 7v to 12v. A 3-cell battery is rerrred to as ‘3S’ and will give your project longer endurance than a 2-cell of the same size. This is an example:
Although the mega will operate with a supply directly from a battery such as that, the other devices require 5v. So you will need a 5v regulator to supply that from the battery. The sensor could use the 5v available from the regulator that already exists on the mega, but the other devices will draw too much current, and will require their own regulators. You will need to look at the load of each of those devices to determine the best arrangement. This is an example of a 5v regulator that would have more than sufficient power for those motors:
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Over voltage is the killer of electronics. If the voltage supplied is what the specification says it should work ok. In you case 5V is what you should be aiming for.
Another consideration, rather than a LiPo battery, NiMH cells might be a better option. These vary from 1.4V fully charged to 1.1V discharged and come in AA or AAA size. Using 6 cells you would get 8.4V to 6.6V over the discharge cycle.
Connect this to the device linked by @Jeff105671 and you would get 5V 5A output. Pololu also make 3.2A & 2.5A version at a cheaper price. All Pololu products I have purchase work very well.
You could use a battery holder like this.
Cut this cable and solder to the Pololu board linked by @Jeff105671 would provide an easy way to connect and disconnect the power. Or just cut the connector on the battey holder and solder to the Pololu board.
I like to make my stuff removable and reusable.
NiMH charging. This can be used and works off a USB port, but will take a few hours to charge and only 4 at a time.
There are other NiMH chargers.
Regards
Jim
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The 9V Battery is not powerful enough to run your setup. It is also too high a voltage for the servos, IR detector and stepper.
I see! So you’re saying the 9V battery doesn’t have enough to power ALL these servos?
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Thank you for walking me through Lipo batteries.
If I’m completely honest, I’m feeling quite daunted by the Lipo battery.
I’m hoping just for a simple & easy solution (something my newbie brain 
can easily build haha).
Do you think a power bank has enough power to run by 3 servos, 1 stepper and Adafruit Soundboard?
What do you think of this power bank? https://www.amazon.com.au/ROMOSS-30000mAh-Portable-Charging-Recharging/dp/B07H49NP8B/ref=sr_1_5?dchild=1&keywords=power+bank&qid=1633153325&sr=8-5
I’ve seen power banks used on remote cars before: ArduCar - Power Bank Powered 2WD Arduino RC (Bluetooth Co... - Arduino Project Hub
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Thank you Jeff!
Do you think a power bank has enough power to run by 3 servos, 1 stepper and Adafruit Soundboard?
What do you think of this power bank? https://www.amazon.com.au/ROMOSS-30000mAh-Portable-Charging-Recharging/dp/B07H49NP8B/ref=sr_1_5?dchild=1&keywords=power+bank&qid=1633153325&sr=8-5
I’ve seen power banks used on remote cars before: ArduCar - Power Bank Powered 2WD Arduino RC (Bluetooth Co… - Arduino Project Hub
I’m scared of the over-voltage situation you mentioned. I’m hoping this power bank doesn’t break the Arduino.
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I have said it many times before but will say it again.
Power banks are chargers. That is a device containing larger batteries and some electronics to charge phones and other similar devices.
THEY ARE NOT power supplies. Under nil or light loads they are likely to switch off thinking the phone or whatever is charged and it is no longer required. Some do some apparently don’t, mine do. If I plug in a cable and the load is less than about 100mA it will switch off in a few seconds and you have to press the on button or reconnect the cable and the whole process will repeat.
So if you use one of these don’t be surprised if you have to reset it all the time when the load stops.
Cheers Bob
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Hey Tina,
I’d definitely go with James’ suggestion of going with a 5V plugpack to get started, this one will let you test all of the parts individually: 5V DC 4A Fixed 2.1mm Tip Appliance Plugpack Australia
PS: powering from a USB port can get a bit dangerous, theyre usually attached to a pretty expensive computer, so uploading code to the microcontroller is usually all you want to do from a PC. Projects that have motors, or big capacitors attached be weary with the wiring!
With the lights you can dim them in software to draw less current, most libraries allow you to set a limit to the brightness and even above 20% they are staggeringly bright.
Once you have calculated a mean current draw or have everything going on the bench at that point it would be good to size a battery. To measure the current you could use a multimeter in current measurement in series with your plugpack (DONT PLUG THE MULTIMETER INTO THE WALL SOCKET!!) and take the current reading.
Since all of your parts can run from 5V the calculations should be a bit easier, you can take your expected time of use (duty cycle) multiply it with the current and then add all of them for each component.
Allow for the peak current to be at least twice that of what you measure or calculate and the capacity is derived from how long you want it to last.
For projects with a lot going on a LiPo is a pretty safe bet but they can be very dangerous, and need to be respected.
Here are a couple of excellent guides: Powering Portable Projects: Batteries - Tutorial Australia
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Power Banks provide 5V suitable for charging a phone, they will not break the Arduino, they will work ok. But as @Robert93820 has said some Power Banks need a certain amount of current to stay switched on.
The following links are 2 types of Power Banks I have used, as power supplies for my projects.
Have just tested the 2000mAH and it stays switched on, the 5000mAH switches off after a minute or so, running a LED at 6.2mA.
I connected a MEGA 2560 to the 5000mAH Power Bank with only the blink program running. Draws about 60mA and it stays on. The drop out of the Power Bank seems to be less than 50mA.
So, a Power Bank might be a solution; keeping in mind what @Robert93820 has said.
Cheers
Jim.
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thank you robert!
great point!
i was reading liam & james’ post about measuring current. so what i might do is learn to measure the current first and then see what can power it.
hope you’re having a wonderful weekend! 
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thank you jim for sharing your power bank findings!
i plugged my power bank in just now (had one eye half closed in case anything exploded), but it seems to work! all my components are whirring around happily… for now… 
thank you and @Robert93820 @Jeff105671 @Liam120347 for helping me out! i really appreciate it. i feel like these forums are kind of like what it’d be like in a real workshop. where when someone has a problem, everyone in the workshop crowds around the person’s bench and tries to solve the problem together.
i’m learning so much!
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Hi Teena
When measuring current your meter must be connected in SERIES with the load.
If using a Digital Multimeter use the 10A range. This will give yo a good enough resolution (mine has a resolution of 1mA on 10A range but may not apply to all). At 5V the voltage burden will be too great on the mA ranges and what you read will be meaningless in the real world when you remove the meter.
Measure each of your bits and add them up then double it. That will give you some idea of required battery or other power source size.
Cheers Bobsize
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Hi Teena
I hope not. The last thing you want when faced with a dilemma (won’t call it a real problem) is everyone over your shoulder offering conflicting advice. One generally stays clear until asked to assist.
Cheers Bob
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