Regarding Smart Pushbutton ON-OFF Control

[sakibnaz]

Hi there.

I am working on a IoT Wireless Device project which will be essentially a commercial product. The device will be Battery powered (Li-Po 3.7V 5000mAH) and its mainly consist of an ARM CPU Module, BLE nRF52832 MCU and some other necessary circuits (Like Power Regulator, Battery charging, USB, LCD etc).

Now I want to implement a single Pushbutton based Power ON-OFF (Same like smartphone) as well as User-Input. So I want basically below:

- When Device OFF: Press Pushbutton will Power ON Device (i.e. CPU Module)
- When Device ON: Press Pushbutton will act as an User-Input
- When Device ON: Press and Hold Pushbutton few sec (example 10 sec) will force shutdown the device

I know there any some dedicated Pushbutton Controller IC. I checked STM6600 which looks good but its expensive.

-# Any anyone suggest a low cost IC solution achieve my need? ... similar to STM6600?
-# Also as my Device have an extra MCU nRF52832 ... then how about use that as the Pushbutton Controller? Is it a good idea to use MCU for this? Or dedicated Controller IC is better?

Please advise.


Thanks in advance.

Regards.

 

[KlausST]

Hi,

Why not:
* Make the pusbutton to switch ON the power .... and give the pusbutton signal to a microcontroller pin.
* use another microcontroller pin to keep the power supply ON

The rest is software.
* after Reset: switch the pin to keep power alive
* on key press .... do whatever you want
* on long key press ... switch OFF power supply

Klaus

 

[sakibnaz]

Hi thanks @KLAUS ... can you please advise any schematic for this application?

Also my concern is about using dedicated controller like STM6600 and any MCU. There are always low cost small MCU. Then why dedicated controller used? Everyone should use small MCU to save cost.

My another concern is ... in case if MCU in gets hang then what will happen? My Device don't have Battery Connect-Disconnect access. Battery will be inside the Enclosure and user can not access it unless unscrew the Enclosure.

I am not biased to either dedicated controller or MCU. I just shared my application and I like to do the way a commercial product gets designed.

Please advise.

Regards.

 

[KlausST]

Hi,

You are free to design what ever you like. You don´t need to use a dedicated controller. You are the designer, you set up the requirements.

*********
I don´t have the time to draw a schematic, but it should be straight forward.

You will have a voltage regulator for the microcontroller...Maybe it has an ENABLE input, then use this to switch ON/OFF. Or use a P-Ch MOSFET, or a high side switch, or a simple battery protection circuit ... it all depends on your requirement, voltages, currents, timings....

Currently we don´t know much about your design.
*********

in case if MCU in gets hang then what will happen?

You must not ask, you have to specify it. It´s your job.
You are free to use a software timeout, a hardware timeout, a low battery switch OFF, MCU internal watchdog, an external watchdog, no circuit at all... or any other idea.

**********

Generally a froum is not meat that others do your job. You have to show the requirements (all at once, not piece by piece). You have to draw sketches, flow charts... and so on.

We will help you to rectify mistakes. We will tell you how to improve your idea.

Klaus