[sdiy] FSR-controlled CV/LED

[Derek Holzer]

Hi Tom,

just for clarity, looking at the FSR Current-to-Voltage Converter on 
page 23 of the PDF you sent.... VREF going into the FSR should be 
biased?

And do I need to similarly bias the VOUT of that circuit before it 
becomes the VIN of the linear LED driver you also linked to?

Best!
Derek

On 26/9/12 6:38 PM, Tom Wiltshire wrote:
> The FSR "integration guide" suggests using the FSR from a voltage to 
> an I-to-V convertor for better linearity. E.g. with the FSR as the 
> input resistor of an inverting op-amp arrangement (pg 23 onwards).
>
> http://www.sparkfun.com/datasheets/Sensors/Pressure/fsrguide.pdf
>
>   If you're running an op-amp off +9V, you'll need to bias the +ve 
> input to half-supply with a couple of resistors and a cap. This can be 
> copied from lots of guitar effects schematics.
>
> You could then try following that with one of the 'more linear' LED 
> drivers that Justin was asking about the other day. One of the 
> favourites was this circuit:
>
> 
> http://webphysics.davidson.edu/Course_Material/Py310/WK13_circuit3.jpg



-- 
derek holzer
noise.art.technology
http://macumbista.net


-- 
derek holzer
noise.art.technology
http://macumbista.net