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sirri

1 Battery (JT) Power Source for MSP430 Launchpad ^_^

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post-30056-0-76013300-1367332535_thumb.jpgYou are right, sorry for my messed breadboard : )

Here is an updated photo. Same messy breadboard but photoshopped.. Grayed out the "irrelevant" regions..

(Of couse LCD has nothing to do with this indeed)

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The Joule Thief is only suited for applications where lack of regulation and extreme ripple are not an issue -- such as pulsing an LED.

 

If you want a cheap and simple regulator boost regulator to *reliably* power an msp430, take a look at the Microchip MCP1623, MCP1624, or MCP1640.

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indeed.. i am just testing and i have similar stability and reliability concers as yours.. so before i send the diagrams (which is not that hard) i want to test it on my own a little bit..

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sirri what is the point of that? You can use 2pcs AAA, or if the size and weigh are concern then use CR2032.

 

it's fun to experiment, i tried w/ success on attinys long time ago. again depend on the application (i.e. how u draw current).

 

ti has this application note http://www.ti.com/lit/an/slaa105/slaa105.pdf which requires 4 transistors + some common components.

 

i always wanted to try but never get to it.

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it's fun to experiment, i tried w/ success on attinys long time ago. again depend on the application (i.e. how u draw current).

 

ti has this application note http://www.ti.com/lit/an/slaa105/slaa105.pdf which requires 4 transistors + some common components.

 

i always wanted to try but never get to it.

seems a lot more complicated than JT. maybe only pro may be the lack of using a toroid..

 

sirri what is the point of that? You can use 2pcs AAA, or if the size and weigh are concern then use CR2032.

yeah. indeed i have used 2 pcs of AA batteries in my "Light Alarm Project" CR2032 didn't work to power my 4seg.7 digit LED display. I am just testing, another thing is JT system is told to "suck" the energy of a battery, even below 1 V.. But at normal conditions, i mean using 2 AA batteries let's say, it won't work. indeed, just experimenting ; )

 

The Joule Thief is only suited for applications where lack of regulation and extreme ripple are not an issue -- such as pulsing an LED.

 

If you want a cheap and simple regulator boost regulator to *reliably* power an msp430, take a look at the Microchip MCP1623, MCP1624, or MCP1640.

i will still try it, nothing to lose ; ) lm317 stage is for that indeed, to be (more) sure to stay within safe limits because i know the output of JT is pretty unstable..

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since i got everything needed to built it (the ti example)..... this is an exact realization of the schematic.

 

photo.jpg

 

 

result pretty much in-line w/ what's described in the application note. here is no-load at 2.7V

 

photo.jpg

 

 

below i had it drive a g2452 project. it settled at 1.9V which is a bit disappointing but it operates. the mcu works but the msgeq7 does not like it and did not behave.

 

photo.jpg

 

 

 

i kind of like it as it could potentially shrink some project to 1xAAA power.

 

i know u can get 1.5v boost boards in ebay / dx for $3.00 but it is fun to play w/ transistors and real components too.

 

from the application note it was mentioned it can power simple projects (w/o sleep) up to 1000 hours on 1xAA, which makes it practical for real use in many applications.

 

/EDIT add link to ti slaa105 application report http://www.ti.com/lit/an/slaa105/slaa105.pdf

//EDIT fix pics

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When I read this article "Run an uC from an AA-battery" http://spritesmods.com/?art=ucboost&page=3 , I was wondering how can I duplicate it on msp430.

I notice that there are some extra parts. Well I still need inductor and battery but other parts are not needed. In msp430 itself there is clamp diodes from any pin to ground and to Vcc and there is switching transistor. So scheme is like this: The negative terminal of battery goes to GND pin of msp430. The positive terminal of battery goes to inductor and the other inductor pin goes to one of GPIO pins of msp430, for example pin P1.4. On Vcc and GND pins of msp430 there is 6.3V 2200uF capacitor. Then you need this code:

#include <msp430g2553.h>
#include <stdint.h>

#define SW BIT4
#define power 5
volatile uint8_t pwm;


void main(void)
{
  BCSCTL1 = CALBC1_16MHZ;                    // Set DCO
  DCOCTL = CALDCO_16MHZ;

  WDTCTL = WDT_MDLY_8;                    // WDT interval timer
  IE1 |= WDTIE;                             // Enable WDT interrupt
  P1OUT &=~SW;                              //

  _BIS_SR(LPM0_bits + GIE);                 // Enter LPM0 w/interrupt
}

// Watchdog Timer interrupt service routine
#pragma vector=WDT_VECTOR
__interrupt void watchdog_timer(void)
{
  if(--pwm==0){
    P1DIR |= SW;
    pwm=power;
  }
  else{
    P1DIR &= ~SW;
  }
  
}

Inductor have to be very special: it have to be with right induction so voltage doesn't go very high or very low, not stressing clamp diodes(they can handle only 2mA) and it's coil must have the right  resistance so it will not stress msp430 switching transistor.

 

I didn't build it. Because I don't have any coils in my part bin and as I said 2pcs of AAA or one CR2032 battery.is better than that.

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