Propeller and Vibra Tab

TinkersALot

For the parallax Piezo Film Vibra Tab Mass sensor at:

http://www.parallax.com/Store/Sensors/PressureFlexRPM/tabid/177/CategoryID/52/List/0/Level/a/ProductID/89/Default.aspx?SortField=ProductName%2cProductName

There is a circuit described in the pdf at:

http://www.parallax.com/Portals/0/Downloads/docs/prod/compshop/PiezoInfo.pdf

Is that circuit "safe" to use for a propeller input pin?

if not, then what mods would be needed?

Whit

TinkersALot,

The circuit diagram shown on the pdf is for a Basic Stamp which uses 5 Volt I/O signals.

See this thread on safely connecting a 5 Volt signal to a Propeller. http://forums.parallax.com/showthread.php?p=585920

It is recommended that a 1k resistor be placed between a 5 Volt signal and a Propeller Pin.

So I think you could do it that way - though there may be better thoughts from others.

I have used the Vibra Tab with a Basic Stamp, but not with the Propeller. It is a neat sensor and works well.

Also on the Vibra Tab page, there is a link to the Object Exchange Sensor's page, but I could not find an object for the Vibra Tab - If there is one, it may have some connection info.

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Whit+


"We keep moving forward, opening new doors, and doing new things, because we're curious and curiosity keeps leading us down new paths." - Walt Disney

TinkersALot

Thank you, Whit --

I did peruse the thread you referenced. There was a lot of information packed into that little gem. Your additional comments on the sensor itself are also very encouraging. With the newfound confidence that "I won't make smoke" I am even more eager to wire up the little wiggler to the propeller

I did not see any obex entry for the device as well, but as it looks like a simple level test, it seems that ina is all that is needed to read from the little wiggler.

Thanx again!
TinkersALot

Little-endian

I know this is an old thread, but after being recently inspired by the "Laundry Alert" project (http://www.parallax.com/LaundryAlert/tabid/883/Default.aspx) I was wondering if it might also be possible to detect a running appliance (washer, dryer, dehumidifier) using a sensor to measure its vibration. In my case, I really don't care about how much it's vibrating, just whether or not the appliance is running. I know an accelerometer can do this, but I really don't need to measure the amount of vibration. In searching for a sensor I found the inexpensive Vibra Tab and this thread. Anyone know if the Vibra Tab would be a good choice for a Propeller application to determine when a washer, dryer, dehumidifier, etc. is running?

T Chap

The 5.1v zener is there to limit the voltage max. You can use a limit resistor as stated, but you can also sub in a 3v3 zener or close to prevent some higher voltage if the tab gets hit hard. If you wanted to, you could connect a scope to the tab and see what the max potential voltage spike is, and work from there.