New Schematic Part 2

A project log for Open Source Smart Watch

Based on the stm32f4 cortex-m4 mcu, 1.44" TFT LCD , HC-05 and Android App.

montassarMontassar 10/18/2015 at 07:514 Comments

In the previous update, I posted a new schematic of a custom board for this project based on the STM32F407VG ( obviously ) . Soon after I decided to edit go over it again and remove some parts which I thought I can replace the regulator & the usb port and replace it with a 2 pin header that will later on connect to one of these cheap/small modules for voltage regulation and battery control.

3.3V linear voltage regulator.

LiPo battery charging module from sparkfun.

I had 2 main reasons behind this decision : First is to reduce the work necessary to get this up and working later on & simplify the PCB design process as much as possible. The second is having these modules laying under the main board and reduce it height & width.

The Gerber files will be soon submitted to OSHPARK if no one points something odd on the schematic.

Currently in work:

I'm currently working on the website for this project. It's gonna be a place where I share all the resources behind this project including schematic files, source code.


K.C. Lee wrote 10/18/2015 at 18:00 point

AMS1117:  Quiescent Current: 5mA (typ) 11mA (max).
There are LDO out there that consumes a lot less current.  Even a Buck converter like this consume 1/100X quiescent current.

  Are you sure? yes | no

Montassar wrote 10/18/2015 at 18:21 point

Indeed , however I was not really concerned about the power consumption at this point so I threw in the AMS117-based module as an example. Thank you for the reply. By the way I see you used an "MCP1700T-3302E/TT" in one of your similar projects.

  Are you sure? yes | no

Montassar wrote 10/18/2015 at 16:14 point

Still though the voltage regulator wins. It's the standard within something like this. As for the power consumption, i believe the software will be the major player in that. Also using a BLE module instead of the HC05 will save me a couple of mA.

  Are you sure? yes | no

8bit-bunny wrote 10/18/2015 at 15:22 point

3.3V linear voltage regulator. <-- a buck converter will comsume less power, resulting in longer battery life ;)

  Are you sure? yes | no