Conversion

Lizzy1118

I created a Program in Basic Stamp which has to be used to run a FlexiForce Sensor...I need to know how can I convert the output from time to force???

Mike Green

You need to provide more information about what you're doing. At the very least, provide your source code and a description of how you have things connected.



If you're referring to the use of RCTIME to measure the resistance of the sensor where RCTIME provides a time value, you'll have to calibrate your system using test weights. The BASIC Stamp Syntax and Reference Manual discusses the use of RCTIME to measure resistance and shows how the resistance can be calculated from the capacitance used and the time measured. Look at this article from the manufacturer's FAQs. In addition to using curve fitting to get an equation for force vs. resistance, you can use the Stamp's LOOKDOWN statement.

NWCCTV

You mean something like this? I used this and once the pressure on the sensor hit the 50000 it would move my bot forward.

IF rawforce >=50000 THEN
FREQOUT 4, 1500, 1000
FREQOUT 4, 1500, 1500
FREQOUT 4, 1500, 2000
FOR counter = 1 TO 300
PULSOUT 13, 2030
PULSOUT 12, 1627
PULSOUT 14,1650
PAUSE 20
DEBUG CLS
NEXT
ENDIF

Lizzy1118

This is my program,

Code:

' {$STAMP BS2}
' {$PBASIC 2.5}

time VAR Word
sensorPin CON 15
DO
HIGH sensorPin
PAUSE 100
RCTIME sensorPin,1,time
DEBUG HOME, "time = ", DEC5 time, CR

IF time>10 THEN
HIGH 14
PAUSE 500

ELSE
LOW 14
PAUSE 500
ENDIF

LOOP

The program objective is detect the force applied on a flexiforce sensor, if the force applied is greater than the number assigned then power on a LED, I need to convert the RCTIME into force.

Tracy Allen

This same question came up here on this forum about a week ago, too, how to convert the RCTIME value to force, from the flexiforce sensor. Basically, force is inversely proportional to resistance.

NWCCTV

Still using RCTIME change time to rawforce. Worked for me.

' {$PBASIC 2.5}
' {$PORT COM1}
' -----[ Declarations ]----------------------------------------------------
counter VAR Word
rawForce VAR Word ' Stores raw output
sensorPin PIN 14 ' Flexiforce sensor circuit
duration VAR Word
' -----[ Main Routine ]----------------------------------------------------
Measure:
HIGH sensorPin ' Discharge the capacitor
PAUSE 2
RCTIME sensorPin,1,rawForce ' Measure RC charge time
DEBUG HOME, "Flexiforce raw output = ", DEC rawForce,CR

IF rawforce >=50000 THEN
FREQOUT 4, 1500, 1000
FREQOUT 4, 1500, 1500
FREQOUT 4, 1500, 2000
FOR counter = 1 TO 300
PULSOUT 13, 2030
PULSOUT 12, 1627
PULSOUT 14,1650
PAUSE 20
DEBUG CLS
NEXT
ENDIF
GOTO Measure

Lizzy1118

Thanks, I appreciate everyone's help.