Table of Contents

Introduction

This project uses one of the analog to digital converter (ADC) channels on the TINKERplate to measure and evaluate the capacity of a standard 1.5V alkaline battery.

Required Parts

This project only requires a TINKERplate connected to a programmed Raspberry Pi and two wires

Steps

Assembly

The assembly consists of simply attaching a pair of wires to the Analog Input block as shown here:

When testing, place the red wire pn the positive terminal and the black wire on the negative terminal.

Code

We used the code shown below for our tester. In our program we sit in a loop that samples the voltage on analog channel 1 twice every second and display the data to a panel meter. To make it a little interesting, we base the color of the meter and the wording in the label on the battery voltage.

The output from a GOOD battery:

The output from an OK battery:

And the output from a BAD battery:

Note that you could modify the threshold voltages in the above code to test 9V alkaline batteries, lithium batteries, and 6V lead acid batteries.

Here is the code ready for copy and paste:

import piplates.TINKERplate as TINK
import time

#create battery state thresholds
VL=1.2
VH=1.4

TINK.openMETER(1)   #Create a panel meter on the screen

#Change window title:
TINK.setTITLE("TINKERplate Battery Tester") 
#TINK.setCOLOR((255,0,0))   #start with red text

while(True):
    bat=TINK.getADC(0,1)            #read analog chanel 1
    if (bat >= VH):
        TINK.setCOLOR((0,255,0))    #show green text
        TINK.setMETER(bat,'Volts','GOOD',1) #indicate a GOOD battery
    if ((bat >= VL) and (bat < VH)):
        TINK.setCOLOR((255,255,0))  #show yellow text
        TINK.setMETER(bat,'Volts','OK',1)   #indicate an OK battery
    if (bat < VL):
        TINK.setCOLOR((255,0,0))    #show red text
        TINK.setMETER(bat,'Volts','BAD',1)  #indicate a BAD battery
    time.sleep(.5)                  #delay and repeat

import piplates.TINKERplate as TINK

import time

#create battery state thresholds

VL=1.2

VH=1.4

TINK.openMETER(1) #Create a panel meter on the screen

#Change window title:

TINK.setTITLE("TINKERplate Battery Tester")

#TINK.setCOLOR((255,0,0)) #start with red text

while(True):

bat=TINK.getADC(0,1) #read analog chanel 1

if (bat >= VH):

TINK.setCOLOR((0,255,0)) #show green text

TINK.setMETER(bat,'Volts','GOOD',1) #indicate a GOOD battery

if ((bat >= VL) and (bat < VH)):

TINK.setCOLOR((255,255,0)) #show yellow text

TINK.setMETER(bat,'Volts','OK',1) #indicate an OK battery

if (bat < VL):

TINK.setCOLOR((255,0,0)) #show red text

TINK.setMETER(bat,'Volts','BAD',1) #indicate a BAD battery

time.sleep(.5) #delay and repeat

The above code can be downloaded from github by typing the following instructions on the command line:

git clone https://github.com/pi-plates/TINKERplate-Projects.git
cd TINKERplate-Projects
python3 BatteryTester I.py

Theory

We based our threshold voltages on the blue line in the chart below.

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