Testing for a specific voltage of 220v DC on a remote device

Gravity Boy

I am using the stamp to trigger a remote device that uses a capacitor that builds up a charge of 220v DC. I want to set a flag that tells me when that device has a fully charged·capacitor. I thought about building a voltage divider that would put a lower voltage to one of the pins, but don't think this is the best method.

sam_sam_sam

Gravity Boy

·Welcome to the ParaLLAX Forum

BE VERY CAREFUL WORKING·WITH VOLTAGES THIS····· HIGH·AND·WITH··A· CAPACITOR

·Also use a 10 k ohm resister to discharge the capacitor before touching the terminals other wise this could happen to you

This enough to give·you a very BAD SHOCK and this·CAN BURN·YOU if you are not careful


You would need a resister that has a value of 250000 ohms to 125000 ohms this may need to be·ADJ·value depending on when you want it to be trigger but start there

Do this with an LED first you just want the led be light just enough to be seen and no more than that

To get the value of the resistor that is need if you use a green Led the start to light is about 1.7 volts so if you get it there· you will need a little high value resistor to get it to 1.2 volts for the Optic Sensor

Then use optic sensor like any··one of these··· 4N25 , 4N26 , 4N27 , 4N28 , 4N35 , 4N36 , 4N37, H11A1M , H11A2M , H11A3M , H11A4M , H11A5M

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···················· This·very important



MAKE VERY SURE THAT YOU DO NOT MORE THAN 1.3 volts at these pins on Pins 1 and Pin 2

Do this with an LED first you just want the led be light just enough to be seen and no more than that

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Pins (1 +) and (2 - )·are your input this where you will use this value· 250000 ohm resister and hook up to the··capacitor

Use only value that is need to trip the Optic Sensor

250000 = 0.001 amps 1/4 watt····· Try this value first

125000 = 0.002 amps 1/2 watt

83000·· = 0.003 amp 3/4· watt

I would use two·that (= from·125000 to 62500)·one on each pin that way you can measure the voltage at the Optic Sensor pins

Pin 5 will be VDD this 5 volts·

Pin 4 will have a 10k ohm resister and goto VCC

Pin·4 will also have a 220 ohm resister· which will be trigger for your Basic Stamp I/O Pin 0 to 15 just pick one

Then Read this


What’s a Microcontroller?

Chapter #3: Digital Input - Pushbuttons · Page 71

Here is the Link to it

http://www.parallax.com/Portals/0/Downloads/docs/books/edu/Wamv2_2.pdf

In your case you just would not use the switch

·(your switch would be the Optic Sensor)·but every thing else would be the same

code wise

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··Thanks for any··that you may have and all of your time finding them

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Sam

Post Edited (sam_sam_sam) : 8/12/2008 1:05:32 PM GMT