Reading sensors with 3.3v(beginner)
Hi everyone, I'm planning to read several sensors(accelerometer, ambient, barometric, Temp and 5v battery) on PORTA using pic18F4550 on 5v supply. My first question is my accelerometer module has an analog output x, y and z with 3.3v supply...can I simply use ADCIN command for the accelerometer output pins?
Thanks in advance,
tacbanon
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Re: Reading sensors with 3.3v(beginner)
Yes, but you may want to set the ADC reference voltage to 3.3.
But why not just run the 18F4550 at 3.3?
Dave
Always wear safety glasses while programming.
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Re: Reading sensors with 3.3v(beginner)
Yes, you can run the 18F4550 at 3.3V like Dave said. If you are concerned with the USB module in the18F4550 not working with Vin=3.3V, there is a way to make the module work at 3.3V.
"No one is completely worthless. They can always serve as a bad example."
Anonymous
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Re: Reading sensors with 3.3v(beginner)
Hello Dave and rsocor01, I think among the sensors (accelerometer, ambient, barometric, temperature and 5v battery) I'm planning to incorporate, the accelerometer is only the one that have 3.3v...that is why I tend to use the 5v source...any input is much appreciated on how to approach this.
Kind regards,
tacbanon
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Re: Reading sensors with 3.3v(beginner)
USB signals are 3.3 already....If you are concerned with the USB module in the18F4550 not working with Vin=3.3V, there is a way to make the module work at 3.3V.
tacbanon,
Are the remaining sensors analog or I2C, or...
Dave
Always wear safety glasses while programming.
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Re: Reading sensors with 3.3v(beginner)
Not really concern with the USB part as of now...Originally Posted by mackrackit
Sensors and modules:
Barometric - SPI
Ambient - Analog - (Done)
Temp (DS18B20) - Digital
Battery monitoring - Analog (Done)
Accelerometer - Analog
RTC - I2C (Done)
SDCard - SPI (Done)
I will try to look for an I2C accelerometer sensor if this will be easier...but it will take me another few days to get one. I have the ambient and Battery monitoring working. I also have an RTC and SDCARD on board running for data recording...
Thanks for the time helping.
/tacbanon
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Re: Reading sensors with 3.3v(beginner)
Most people use this setup to make the USB module work
http://www.mecanique.co.uk/products/...atic-large.gif
with Vcc = 5V. What I meant is that it can be done with Vcc = 3.3V.
Last edited by rsocor01; - 21st September 2012 at 05:54.
"No one is completely worthless. They can always serve as a bad example."
Anonymous
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