Subject:
|
RE: Help with connecting pyroelectric sensor
|
Newsgroups:
|
lugnet.robotics
|
Date:
|
Tue, 7 Sep 1999 14:19:30 GMT
|
Viewed:
|
665 times
|
| |
|
|
> You need at least part of the circuit with the opamp. All the diodes, C1
> and R1. I doubt you need a +5v regulator for the supply, but you need a
> 2.5v reference. Maybe you can just use a resistor divider for that. I
> can't tell how much ouput the thing makes, so you may need the opamp.
> Normally R1 is a 1K. BTW the block diagram for the part shows the reference
> and output reversed.
I'd use one of the little reference diodes that make a precise 2.5 volt level
from a dropped Vcc. I think it's an LM375-2.5. The reference is probably
there to guarantee a certain output for a certain range, independent of the
supply voltage. If you use a resistive divider off Vcc, then the output
for a certain distance will probably vary with battery voltage...
I agree that you don't need the +5 regulator since the description says
you can use 5-15 volts. The op-amp may not be necessary on the output side,
but most of these low power beasts don't have really good buffering, so I'd
put it in.
Free advice, and worth every penny...
Cheers,
Ralph Hempel - P.Eng
--------------------------------------------------------
Check out pbFORTH for LEGO Mindstorms at:
<http://www.hempeldesigngroup.com/lego/pbFORTH>
--------------------------------------------------------
Reply to: rhempel at bmts dot com
--------------------------------------------------------
|
|
Message is in Reply To:
 | | Re: Help with connecting pyroelectric sensor
|
| <lego-robotics@crynwr.com> wrote in message news:84e2ed7a.250598...aol.com... (...) I (...) at (...) max (...) You need at least part of the circuit with the opamp. All the diodes, C1 and R1. I doubt you need a +5v regulator for the supply, but you (...) (25 years ago, 7-Sep-99, to lugnet.robotics)
|
3 Messages in This Thread:
 
- Entire Thread on One Page:
- Nested:
All | Brief | Compact | Dots
Linear:
All | Brief | Compact
|
|
|
|
