Hi!
I've been investigating about powering an Arduino nano with a 3.7 V battery, but so far I found that 5 V is recommended. However I found some projects online with a 3.7 V (Lipo or not) and working:
Do you any have experience with this? Thanks!
If you want it to be
If you want it to be strictly 3.7V on a 5v/16mhz arduino, it is possible, but a bit out of spec.
Here are some helpful links:
https://learn.adafruit.com/arduino-tips-tricks-and-techniques/3-3v-conversion
http://aeroquad.com/archive/index.php/t-2866.html?s=114dc42f870a7d26159e65859fe238fa
Great mod for arduino boards!
Thanks robomaster!
Ok, that’s a good way to mod the arduino boards to work fine with 3.7 V Lipo boards. At the end of the second link there are some concerns and tips regarding operating frequency and voltage for arduino micros…
Due to the “definetive” way of this mod, and because step up voltage converters are so cheap, I think this mod is better only if the project is for long term. Also it’s maybe a bit more power efficient, that with low power applications and running with small bateries can be considered.
AVR are made for low power
AVR are made for low power applications, as low as 0.7v . The nanos at <5v will work a little slower, analog pins will be glitchy and the 5v and 3v3 regulators will provide a lower voltage.
A really easy way to conver a nano to low power would be to bypass the 5v regulator and desolder the clock. Without the regulator it will have full power and without the external clock it will use the internal clock, which is at 8Mhz.
There are two kinds of the
There are two kinds of the Pro Mini boards, one with 8Mhz for 3.3V, and one with 16Mhz for 5V. In practice, you can power both of them with the 3.7V from a LiPo, but you approach it differently.
I’m mostly using the 3.3V model in my recent robots, and just power them through the RAW pin as you would normally do. The internal linear regulator drops that to the required 3.3V and all the functions of the board work correctly.
With the 5V board, you need to bypass the internal regulator (which wants to regulate down to 5V, which is not possible with 3.7V coming in), and power the board through the VCC pin directly. You will get the board running at 16Mhz at 3.something, which is technically overclocking the AVR chip, but works fine in practice. One thing that will not work is the internal EEPROM, which apparently requireds higher voltage (especially writes).
Learning more on AVR
Thanks Silux!
These details are very useful. Let me check them to see how to use it. Thanks!
Thanks deshipu!
These details are very interesting… just wandering, did you test them?
I think all this topic maybe deserves a whole post topic…
As I mentioned, I am using
As I mentioned, I am using those 3.3V pro minis in all my recent robots, so those are tested pretty well.
I only tested the 5V one briefly, I don’t use it in any permanent project, so I’m not sure about long-term effects.
I use the Adafruit Trinket for 3v3.
When I want a small Arduino, I use the Adafruit Trinket 3v3. They also have a 5v one but I can get ebay clones cheaper.
I got a few before I realized that ebay had clones much cheaper.
The Teensy 3.1 also runs on 3v3 and should be able to run on a single LiPo.
Thanks for the details
Ok thank you deshipu. As I saw the pro mini hasn’t USB connector and operating voltage is lower, also less memory and analogue I/O vs arduino nano.
Right, if you need the USB
Right, if you need the USB connector, use Nano, which also comes in 3.3V and 5V versions, but is two times more expensive, due to the included USB2TTL chip. Personally, I use Pro Minis with an external USB2TTL, because this way I can reuse it, but it totally makes sense to use Nano if your project is going to be connected to the computer a lot.
Interesting the Adafruit Trinket 3v3… Pro
Thanks Dangerous,
I saw the Adafruit Trinket 3v3 Pro has more pins and an extra (optional) feature: a backpack for LiPo battery!
That trinket pro has 18 GPIO instead of the 5 from the standard trinket, but even the pro has 6 PWM outputs, 3 work like analogue…
Ah ok!
Ok thanks for the details!
You are right, for some projects having the USB2TTL onboard is great, for others that are “unplugged” it’s not necessary.
