Hello everyone
I am new to arduino, so you will see me frequently asking questions. I just got a book to read about how to program the board, so I'm making progreas.
Anyway, I have an arduino uno. I was trying to upload the basic led flash sketch and use a bluetooth module. When I upload the sketch and have it connected via usb, it is fine. But I have a 3.7V 2000mAh Lipo battery that I have connected to the barrel power input. (I have the charging board and the lipo connected). It is enough power to make the power led light up, but nothing else works, it won't even power the bt module. So I was reading and I guess the minimum input for the barrel part (sorry, idk the technical name) is 5V.
I found this:
If I add that to my set up, will I be able to use the 3.7v lipo?
Also, what would the correct way be to hook up the battery leads to the board? (Not the battery leads, but the load leads from the charging board for the lipo)
You can't connect a 3.7 V lipo to the barrel jack. The barrel jack is the INPUT to the 5V regulator, and as a result, the input voltage must be at least 7 volts when using the jack.
You can use other other options, such as a step-up voltage converter (see polulu), if you want to use the lipo with the DC jack
You could connect +3.7V to pin 5V pin of Arduino and ground pins. Theoretically you could power ATmega328p from 1.8 to 5.5V.
Also, theoretically you could connect the same pins with 5V step-up converter, if you are positive that it output regulated 5V and spikes do not exceed 5.5V or your Arduino will work very short time. From 5V step-up converter schematic I cannot conclude it is safe, without detail testings with oscilloscope...
If you do upper, be positive to detach USB and Barrel Jack, because if you don't, 5V high current (up to 1.5A) will rush into your Lipo battery to charge it, risking immediate fire or explosion!
The best way is to buy breadboard, ATmega328p and 4 to 16MHz crystal oscillators (with few additional passive components) and burn Arduino bootloader for further testings.
arduinomagbit:
you can power ur uno using 3.7v lipo, but connect it to 5v pin, not vin pin.
My bt module goes to the 3.3v. So if I use the bt module to the 3.3v and one ground, I could put the lipo to the 5v and the other ground? I will have to try this when I get home. Thank you for the info.
pwillard:
You can't connect a 3.7 V lipo to the barrel jack. The barrel jack is the INPUT to the 5V regulator, and as a result, the input voltage must be at least 7 volts when using the jack.
You can use other other options, such as a step-up voltage converter (see polulu), if you want to use the lipo with the DC jack
mcufan:
You could connect +3.7V to pin 5V pin of Arduino and ground pins. Theoretically you could power ATmega328p from 1.8 to 5.5V.
Also, theoretically you could connect the same pins with 5V step-up converter, if you are positive that it output regulated 5V and spikes do not exceed 5.5V or your Arduino will work very short time. From 5V step-up converter schematic I cannot conclude it is safe, without detail testings with oscilloscope...
If you do upper, be positive to detach USB and Barrel Jack, because if you don't, 5V high current (up to 1.5A) will rush into your Lipo battery to charge it, risking immediate fire or explosion!
The best way is to buy breadboard, ATmega328p and 4 to 16MHz crystal oscillators (with few additional passive components) and burn Arduino bootloader for further testings.
So in other words, I better check my voltage. If you were attempting this, which way would you do it? I have a voltage meter to double check everything, but I know if I am not 100% sure on how to do it, it will catch fire if I mess up. And as of right now, I am not 100%.
Rooster:
So in other words, I better check my voltage. If you were attempting this, which way would you do it? I have a voltage meter to double check everything, but I know if I am not 100% sure on how to do it, it will catch fire if I mess up. And as of right now, I am not 100%.
If you intent to use your Lipo battery, be sure first you have detached any external power - USB cable and power supply from Barrel Jack, then you can connect battery. And of course do not attempt to plug it back while battery is connected. Otherwise, risk fire or explosion of your battery.
If you intent to use 5V step-up converter, be sure it output 5V regulated voltage. ATmega328p (as any micro controller) require stable supply and voltage not exceed maximum specified, in this case 5.5V. Without oscilloscope, you cannot certainly confirm stability, as common multimeter average results and you cannot see voltage spikes which can be much over 5.5V. That is in case you directly apply 5V in arduino's 5V pin.
If you intent to use your 3.7V battery and 9V step-up converter, plug it to the Barrel Jack or IN pin of arduino. In that case, 5V regulator on the board will provide regulated (stable) 5V to the circuit.
The safest way is to connect +7 to 12V into the Barrel Jack or plug the USB cable which will provide around 5V (with the noise comes from computer, sometimes not quite desirable).
At 3.7v, you are operating the 328p out of spec if you are running it at 16mhz, like an Uno typically would. You need to bootload it with a 8mhz bootloader (you want the lilypad bootloader, 8mhz optiboot - burn bootloader with that selected will also set the fuses for 8mhz internal instead of external). At that point you may be better of getting a 3.3v/8mhz arduino pro mini (or clone) and FTDI adapter.
Particularly since you probably care about the battery life - boosting the voltage up to 9, only to drop 4v in the regulator is hardly a good way to improve that battery life.
3.7V is the low end of a charged LiPo, which will be as high as 4.2V.
Connect it to a charge control board and then to the 5V header.
I think the 3.3V regulator needs more than 4.2V, and certainly more than 3.7V, to make 3.3V power the Bluetooth.
In which case, get a boost regulator from pololu.com to make 5V either connect to the 5V header, or cut up a USB cable and connect to the USB connector.
DrAzzy:
At 3.7v, you are operating the 328p out of spec if you are running it at 16mhz, like an Uno typically would. You need to bootload it with a 8mhz bootloader (you want the lilypad bootloader, 8mhz optiboot - burn bootloader with that selected will also set the fuses for 8mhz internal instead of external). At that point you may be better of getting a 3.3v/8mhz arduino pro mini (or clone) and FTDI adapter.
Particularly since you probably care about the battery life - boosting the voltage up to 9, only to drop 4v in the regulator is hardly a good way to improve that battery life.
I never considered getting the arduino pro mini. Are there any down sides to it? I do have a project in mind that I am working on. If you want to PM me, I'll tell you about it, maybe you can help me some.
So I think my plan is going to use a 5v step up, and go to the 5v header. I will go through an oscilloscope to check the spikes. I do have to order one though.
Or from calc:
4.5-2.7 = 1.8
1.8/10=0.18
0.18*6 = 1.08
2.7+1.08=3.78V
Let me start by saying simply, i don't know. All I am trying to do right now is get my 3.7v lipo to power the board enough to run the bluetooth module and the basic led sketch.
I really need to do more research on everything. I don't know what the mhz is, or any of that. I am a beginner when it comes to electronics. That's why I do not have an oscilloscope yet.
Edit: I know what mhz is, but I don't know what my setup is running at I mean.
Also, what rechargeable battery solution would you all recommend? If not 3.7v, what would you recommend? I want to have it where I can charge the battery through a usb (mini or micro, i don't care). I will just need resistors for my components, which I feel more comfortable with rather than blowing up a battery.
My last question was intended to DrAzzy, as I had no problems so far at all running ATmega328p at 3.3V and 16MHz...
On your questions would be possible to answer when you give detail spec.
There is also many Arduino shields you may buy and use without taking care about all details wrote here. You just have to provide at least +7V and plug it into Barrel Jack when you are mobile.
mcufan:
My last question was intended to DrAzzy, as I had no problems so far at all running ATmega328p at 3.3V and 16MHz...
On your questions would be possible to answer when you give detail spec.
There is also many Arduino shields you may buy and use without taking care about all details wrote here. You just have to provide at least +7V and plug it into Barrel Jack when you are mobile.
What details would you like? If I don't know the answer, I will figure it out. I haven't looked into the shields too much yet. I kind of want to learn to do this the "right" way. I do want to make sure i have all of the details right here first. I do want to pick up an oscilloscope, just so I have it on hand. Then I want to get the 5v step up and connect it to the 5v instead of the barrel port. My worry, like you have said is making sure it doesn't spike. I'm a little nervous to mess with it until I get the oscilloscope (and learn to use it properly). Once I get all of that working, with a basic led sketch with my rechargeable battery (lipo), then I will mess with shields a little.
I wish I knew a better and safer way to charge a battery via usb that will be in the device.
Well, you cannot use and charge your Lipo with Arduino Uno this way. You have to make new project which is not quite trivial, make a PCB...
BTW, according to SparkFun 5V Step-Up Breakout - NCP1402 info:
"... Volts and output a constant, low ripple 5V output capable of sourcing up to 200 mA. This board is great for supplying power to 5V sensors on a 3.3V board, or providing 5V from a AA battery."
Well, from schematic you should look at used parts datasheet and conclude is it suitable to provide 5V to Arduino and your module or not... and test it before use!
All in all, you have to make your primarily spec about the project and then search for suitable modules or in this case Arduino Uno shields. If you cannot find it, you are forced to create your own solution (for beginner that would be very long task), or relax your requirements a bit and use existed solutions or circuits.