basic stamp maximum load

mithun

hi all,

could someone please suggest me about the following:

1. can I connect 3/4 ping sensors to the bs2 homework board.
2. can all of the sensors be activated at the same time? would it
·· exceed the 21 mA limit.





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Bruce Bates

Mithun -

Based on the PING))) Documentation, each PING))) sensor requires 30-35mA per unit. The Homework Board has a 500 mA built-in voltage regulator, so based merely on those specifications, and presuming no other loads (poor presumption!), you COULD operate 14-16 PING))) Sensors without overloading the built-in power supply.

However, since the PING))) supplies a quantitative response (a numeric value) rather than a qualitative response (just HIGH|LOW or ON | OFF) having them "activated at the same time" doesn't make a whole lot of sense, as you'd have no way to field the individual readings, even if you could use them all simultaneously.

Regards,

Bruce Bates

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Forrest

FYI the Rev A and B Homework board have a 50 mA regulator, while the Rev C Homework board has a 500 mA regulator. I wouldn't recommend connecting any Ping sensor's to a Rev A or B board - because you'll exceed the current rating if you connect anything else (like an LED) to the board. See here for more info www.parallax.com/detail.asp?product_id=28158

You could power the Ping sensor thru it's own power supply circuit such as a 9V battery connected to a 7805 or 2940-5 regulator (along with input and output capacitors). Just remember to connect the grounds of the Homework board and the power supply circuit together.