Author Topic: TPA81 problem in readings  (Read 4522 times)

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Offline panzapartTopic starter

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TPA81 problem in readings
« on: July 05, 2008, 02:28:21 AM »
Hello, I'm building a robot with a TPA81 mounted on a robotic arm. The TPA81 uses I2C bus. My problem is that in generally out of the robot it works fine and all the readings are normal. But when I put it in place it starts giving 255 values for all the readings. Is it something like noise from cables? They are about 85cm long. What can I do to solve this?
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Offline izua

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Re: TPA81 problem in readings
« Reply #1 on: July 05, 2008, 07:13:19 AM »
Do you get a consistent i2c signal: ie, the device acknowledges when its address is sent, it responds to the general call address, but only the received value is scrambled?
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Offline panzapartTopic starter

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Re: TPA81 problem in readings
« Reply #2 on: July 06, 2008, 02:36:28 AM »
Well, I managed to fix this.  :o I hooked up on my board two external pull-up resistors (4,7kΩ)  for the SDA & SCL signal and now it seems to work fine. I use an AVR microcontroller which is supposed to have pull-up resistors on. But maybe because of the cable length they are not enough.
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Offline khalchris

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Re: TPA81 problem in readings
« Reply #3 on: October 17, 2008, 10:40:31 AM »
hello ...
i am building a fire fighting robot and using on tpa81 thermal sensor ,any advice or instructions of how to use it,also do i need to attach it on a servo or it needs only to be in one direction...
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