I have to decide which hardware to use in my project, a very important requirement for my project is that the battery life has to be at least 6 months to be a viable product.
Basically what my project does is take a distance measurement every 7 seconds and sends data over wifi every 20 minutes.
Which of these hardware combination is better for battery life?
Can the hc-sr04 sensor run on 3.3v? if not...
Is there any equivalent sensor that runs on 3.3v?
i'm really new to arduino so i don't want to get into designing a circuit with a bare arduino microcontroller.
the reason that i'm looking for a 3.3v arduino board option is that i think these are more power efficient? sorry if it's not i'm a programmer and my knowledge about electronics is VERY limited
i'm planning to use software side techniques to save battery power, i also want to avoid as much as possible a bare bones microcontroller as my knowledge about electronics is very limited and i want to avoid electronic circuit design as much as possible, i would really want to develop in a simple environment, like the options i showed in my first post, however i'll check any other hardware combination that you recommend as long as it's more power efficient than the ones i suggested.
Mmedina_student:
i also want to avoid as much as possible a bare bones microcontroller as my knowledge about electronics is very limited and i want to avoid electronic circuit design as much as possible
Bare bones designs are probably the easiest way to achive low power and extended battery life.
The Pro Mini you linked to may be modifiable for low power use, but how low a current consumption it has would ultimately depend on the specific regulator used.
As for the ESP8266 thing, much the same applies, exactly which regulator have they used ?
Ask Sparkfun what the current consumption of both thier products is in sleep mode, they ought to know.
srnet:
Bare bones designs are probably the easiest way to achive low power and extended battery life.
The Pro Mini you linked to may be modifiable for low power use, but how low a current consumption it has would ultimately depend on the specific regulator used.
As for the ESP8266 thing, much the same applies, exactly which regulator have they used ?
Ask Sparkfun what the current consumption of both thier products is in sleep mode, they ought to know.
Could i run the hc-sr04 sensor with the pro mini i linked?
I'd suggest doing this in two stages. Use standard boards/modules/components to get the functionality of your design correct, then in a second phase, start optimising the power usage.
The "bare bones" design, incidentally, does not add much complexity for a battery powered application. You can get an ATMEGA328P chip with a bootloader installed, and need only 4 additional components (crystal, 2 capacitors and pullup resistor), to have a "Uno" equivalent processing capability. You'd also need a FTDI (or equivalent) programmer for programming via usb or you can configure an existing say UNO for this purpose.
I don't see a point to using a Pro Mini or any non-wifi board when the gizmo is obviously needing wifi.
Furthermore I'm not so sure an ultrasonic distance detector is a sensible method if this is still for your 'is a car in a parking spot' thing.
I'm apt to believe any light based object detection method would be unimaginably more power efficient than having to work an ultrasonic transducer.
How big is the battery? Anything will rin for any period if you have a big enough battery.
WiFi is going to drive the power consumption in this design. If you can't fit a big battery then I expect it will be better to use another radio system going back to another Arduino which is powered.
INTP:
I don't see a point to using a Pro Mini or any non-wifi board when the gizmo is obviously needing wifi.
Furthermore I'm not so sure an ultrasonic distance detector is a sensible method if this is still for your 'is a car in a parking spot' thing.
I'm apt to believe any light based object detection method would be unimaginably more power efficient than having to work an ultrasonic transducer.
The infrared detection sensors that i've checked have a higher mA specification than the hc-sr04 ultrasonic sensor.
i think about the pro mini 3.3v + esp8266 because i think is more power efficient, wifi would only be used every 20 minutes at maximum, maybe a lot more than that but exagerating is necessary here.
As my electronic knowledge is very limited i might be wrong with my logic, that's why i need your guidance choosing the best possible hardware for my project needs.
Project needs to:
Check every 7 seconds if there's an obstacle in 1 meter or less.
Upload data to internet when there is and there isn't an obstacle in 1 meter or less. Exagerating a lot the time between data sends is 20 minutes, it is most likely much more than that.
With that functionality and numbers the Battery life has to be at least 6 months.
MorganS:
How big is the battery? Anything will rin for any period if you have a big enough battery.
WiFi is going to drive the power consumption in this design. If you can't fit a big battery then I expect it will be better to use another radio system going back to another Arduino which is powered.
The battery is something i have to figure out aswell, i'm just focusing on the hardware to choose the best possible solution and then based on power consumption measurements decide which battery to use.
There's no particular requirement for the size of the battery nor the device itself, i think any battery half the size of a car battery could be apropriate for this project.
mA spec of ultrasonic v light really depends on duration.
That ultrasonic module needs 5v, anyway.
Whatever your logic in running two boards instead of one if you care about power efficiency still makes no sense to me.
INTP:
mA spec of ultrasonic v light really depends on duration.
That ultrasonic module needs 5v, anyway.
Whatever your logic in running two boards instead of one if you care about power efficiency still makes no sense to me.
I think there's a misunderstanding. As i mentioned before i have very poor knowledge about electronics, i'm a programmer and this is my first arduino project.
I'm not trying to debate with you that using 2 boards is better, if you think using 1 is more power efficient it should be, please if you can refer me to links to what hardware you would use for this solution, that would help me a lot to clarify what hardware i should use for this project.
No experience in low power WiFi, but I have some questions that might be important.
Is this going to be an Access Point or STation (connected to the house WiFi).
I read in the ESP-12 datasheet that AP is 80mA and ST light sleep is 0.9mA.
Can't you use a different RF link (e.g. 433Mhz) for the device, that connects to a WiFi Arduino inside.
Leo..
OK, "half the size of a car battery" is a good place to start for the battery specification. That's something like 20Ah at 12V, or about 40Ah when converted down to 5V. Divide that by the 4392 hours in 6 months and your target current is 9mA. So you can exceed 9mA for short periods so long as you then have a longer period of less than 9mA.
Once you've confirmed that your average power consumption can get to this kind of level (should not be hard at all) then you can pick an actual battery and re-do the calculations with the battery's datasheet values. Note that self-discharge is going to be an issue - a NiMh battery will go flat in this time period with nothing connected to it.
sorry if it's not i'm a programmer and my knowledge about electronics is VERY limited