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Topic: Power Issues creating sensor read issues (Read 899 times) previous topic - next topic

Postholes

#5
Jan 27, 2013, 10:44 pm Last Edit: Jan 27, 2013, 11:21 pm by Postholes Reason: 1
Running 3 maxbotix range finders:
http://www.maxbotix.com/documents/MB1010_Datasheet.pdf

I plugged the regulated 5v supply into the vcc pin and ground to the vcc ground, the redback isn't working anymore. So apparently that won't do the trick for me. I'm getting lights but it's not doing anything program wise, it's not starting the WiFi and no print statements are running through the initial setup function over the serial port.

I have to present this project on Tuesday so I think if I order a next day air today would it show up Monday (just guesstimates or do I have to wait till Tuesday at 4pm (when UPS normally comes through my area) if I order next day air on Sunday afternoon. Not that it matters much if the power problem is something I'm doing wrong and wasn't the board then I will still have the same problem with a new one....

I'm pretty sure it's the WiFi module that's cooked on this board, everything runs until I try to initialize and run anything through the WiFi module. It was working before I tried the vcc power and immediately after it stopped so just by process of elimination....

Anyhow suggestions on how to save this thing possibly?

oric_dan

The Maxsonars run at 3.3 or 5V, but they probably have a large current draw when pulsing the
transducers. You may have cooked the tiny 3.3V smt v.reg on the pcb. If that's the case, you
could unsolder it, and solder in anything for a replacement, like a TO-92 part, or even an
LM1117-3.3 on a couple of wires.

The 328 itself will no doubt run at 5V, but doubtful the wifi module will run at that voltage.
You may have accidentally applied 5V or 7.4V to the 3.3V buss sometime in the past, and
cooked either the v.reg or the wifi chip, or both.

If you figure the board is basically toast, you might try replacing the v.reg as in the first
paragraph.

Postholes

I talked to linksprite tech support about my problems and they tested the boards that they had in stock. They said that the silk screen has a print error and there is no 5v output on the RedBack, only 3v. However when using the FTDI breakout to power the board it does do 5v output.

Hopefully posting this here will help others that might be using this board. When my replacement shows up I will test the output voltages on both the 3 and 5v output pins using the RAW input power pin and the FTDI power.

Thanks for all the help!

MaxBotix Inc

Hello!  This is Tom Bonar from MaxBotix Inc.

@PostHoles
The current draw of our sensors is not enough to damage a component such as the yellowjacket.  Our LV-MaxSonar-EZ have a max current draw of ~7.5mA and an average current draw of ~2.1 during operation.  The max current draw occurs during the transmit burst of the transducer.  Such low current draws are not capable of damaging the component being used to read or control the sensor.

Our MB1010 sensor referenced in your post will operate at 2.5V DC to 5.5VDC. 

Have you been able to correct the issue? Please let me know if you have any questions by emailing thomas@maxbotix.com and I will be glad to assist you. 

Best regards,

Tom Bonar
Technical Support
of MaxBotix Inc.
Phone: (218) 454-0766
Fax: (218) 454-0768
Email: thomas@maxbotix.com
Web: www.maxbotix.com
Follow us on Facebook at: http://www.facebook.com/pages/MaxBotix-Inc/125159384204938

Technical support and sales are subject to
the terms and conditions listed on our
website at http://www.maxbotix.com/ MaxBotix,
MaxSonar,EZ0, EZ1, EZ2, EZ3, EZ4, AE0, AE1,
AE2, AE3, AE4, WR1, WRA1, and WRLA1 are
trademarks of MaxBotix Inc.

Postholes

Hi Tom,

Thank you for your information and follow up on this problem. I was able to make the sensors work, I had to recalculate the formulas in my sketch but they are functioning now. I am taking 1 reading every 100 milliseconds and every third read I only use the largest value of the three and take three more readings. This, while slow, gives me good information to go on.

The problem I had was a "misprint" on LinkSprites RedBack board. It only has 3v output, but when you use USB to power it the 5v output pin does output 5v. But powering the board through the regulated RAW pin cuts power down to 3v on all output pins. To solve the issue I attempted to use a 5v regulated power supply and the USB VCC and Ground pins. This blew the board when the spec sheet says that this is supported. I had to order another RedBack board from LinkSprite, not sure what to do about the broken one..

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