super low power arduino board with internal clock? + wiring diagram

Projects General Guidance
1

hi

I'm looking for a rather low power arduino board with internal clock, but I don't want to give up too much of ease of use, like easy pc connection etc.

Any recommendations?

The system I want to make:

I want to program a sequence inside the board, e.g., every hour, activate output 1, and 5 minutes later, activate output 2 until a certain amount of pressure is reached.

output 1 is a 5V Solenoid Valve (see link)
output 2 is a DC 3.7V Vacuum Pump Micro Air Pump

I wonder, can I inflate balloons with this pump (see link below)
I also wonder if the valve is open or closed when voltage is applied (to know if I can save power, as it needs to be closed most of the time)
Would this pressure sensor be able to tell when the air inside a balloon reaches a certain pressure? There seems to be no real manual provided for pin 1-6... .

I'm also wondering about the wiring diagram:

Is it as simple as battery --> arduino --> output 1 and 2 in one loop? As in, the arduino powers all this?
Or should the outputs be on separate circuits? With separate batteries? In this case, I have no idea how to connect all components properly (I'm not an engineer).

I'm also wondering about extra components that would come in handy when testing: the right kind of switches, resistors, and what not .

I have 1s lipo batteries from my drone hobby, but maybe regular AA batteries would be safer and longer lasting? I can convert their voltage with resistors to the desired voltage, right? Maybe a 9V battery would be better?

Thank you, yes I'm a total noob as you can see.

2

Have a look at this Arduino on a breadboard tutorial. You can easily program it from a PC with a USB-TTL cable.

Also look at Nick Gammon's low power turorial.

...R

3

A pro mini is pretty much stripped down to the basics - though it still does have a power wasting LED on board (you can remove it if you want, not that hard).

That pump almost certainly doesn't have the power to inflate a balloon. It's a small airpump for aquariums or so. Doesn't produce much pressure or air. I am using the same kind of pumps myself as aeration pumps in small hydroponic setups. Lifetime is pretty poor, but they're cheap at least.

4

A Teensy 3.x series has a built-in real-time-clock. There's a separate Vbatt pin so that you can put a coin cell battery such as a 2032 in to power the clock only while the main part of the Teensy is unpowered.

It seems from your specification that you don't actually need an RTC. It doesn't seem like this must stay in close agreement with the clock on the wall. 0.5% error from 1 hour is probably not significant to you. If that is the case, start from an Arduino with no USB chip, such as a Pro Mini and apply some of the basic power-saving features from Nick's tutorial. That will run a very long time.

Looking at the power consumption of the pumps might be a better way to start the analysis. If the pump runs on 500mA for 0.5% of the time, then your average power consumption is 2.5mA. You don't need to get the Arduino down to the nano-amps level. (1mA = 1000000nA)

5

wvmarle:
A pro mini is pretty much stripped down to the basics - though it still does have a power wasting LED on board (you can remove it if you want, not that hard).

That pump almost certainly doesn't have the power to inflate a balloon. It's a small airpump for aquariums or so. Doesn't produce much pressure or air. I am using the same kind of pumps myself as aeration pumps in small hydroponic setups. Lifetime is pretty poor, but they're cheap at least.

Och damn, I really hoped this pump could generate enough pressure to inflate balloons. It is indeed meant for aquariums. Do you have any idea what kind of pump will do the job? Should be a small pump, and not too heavy for my purposes. And where to get them per piece... it was already very hard to find this one... .

6

MorganS:
A Teensy 3.x series has a built-in real-time-clock. There's a separate Vbatt pin so that you can put a coin cell battery such as a 2032 in to power the clock only while the main part of the Teensy is unpowered.

It seems from your specification that you don't actually need an RTC. It doesn't seem like this must stay in close agreement with the clock on the wall. 0.5% error from 1 hour is probably not significant to you. If that is the case, start from an Arduino with no USB chip, such as a Pro Mini and apply some of the basic power-saving features from Nick's tutorial. That will run a very long time.

Looking at the power consumption of the pumps might be a better way to start the analysis. If the pump runs on 500mA for 0.5% of the time, then your average power consumption is 2.5mA. You don't need to get the Arduino down to the nano-amps level. (1mA = 1000000nA)

hi

Thanks for your suggestions. Yes indeed, the pump will consume a lot more power than the board probably. I guess I will go for the pro mini I guess. So this on will stay on all the time, and calculate how much time has passed since event x... ? And this won't use many milleamps compared to one with a clock that will power itself off between events? Can this board power the pump on and off? Or should I use separate circuits?

Are there any arduino boards that have bluetooth build in? Would that require much power? Can it be linked with a android cell phone? Maybe that's even better than a clock.

thanks!

7

The Simblee is one example of an Arduino-programmable chip which has Bluetooth built in. There are others, but I don't remember their names right now. The Simblee is unique in that the companion app allows the Arduino program to define what's on the screen. It also works as a more conventional Bluetooth, talking to custom apps or other Bluetooth devices.

8

babipsylon:
Thanks for your suggestions. Yes indeed, the pump will consume a lot more power than the board probably. I guess I will go for the pro mini I guess. So this on will stay on all the time, and calculate how much time has passed since event x... ?

Yes - but mind that an Arduino is not perfectly accurate (can be a few % off), and won't remember time between power cycles. If you need better accuracy or time kept over power cycles, use an external RTC (real time clock).

Can this board power the pump on and off? Or should I use separate circuits?

You need some driver hardware, a logic level MOSFET will probably do great.

Are there any arduino boards that have bluetooth build in?

Technically not Arduino but it has Bluetooth: the ESP32. The NodeMCU-32S development board has this processor on board.

9

Ok, thx all and Morgan S and wvmarle, I will try something :slight_smile:

10

Esp32 has an on-board RTC has an ultra low-power microprocessor and can do ATC conversions while under micropower