Author Topic: Hardware issue Axon II with Maxbotix EZ1 sonar  (Read 1505 times)

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Offline SasounetTopic starter

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Hardware issue Axon II with Maxbotix EZ1 sonar
« on: February 22, 2016, 10:00:45 PM »
Hi,

I am having trouble using a Maxbotix EZ1 sonar with the Axon II.

I use that sonar with its analog output pin. In fact I connect the sonar directly on one of the ADC header making sure the ground is connected to ground, power to power and signal to signal.

When I run the program, the sonar always output the same value; 12 cm (very small value, close to the minimum). I was hoping it was a software issue but it is not.

In fact, the sonar works perfectly, when connected to the same ADC pins, as long as it is not powered from the 5V regulated supply (middle pin). If I power the sonar from an external regulated supply and I connect only the ground and signal pins to the Axon then everything works fine (in fact I the ground pin of the sonar is attached to both ground from external power supply and ground pin on the ADC header on the Axon)

As per the spec, the 5V regulated power on the Axon can draw up to 1.5A. So I very much doubt the Sonar uses more than that!

So is this normal ? If not what could be the problem ?

Best regards.

François


Offline Gertlex

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Re: Hardware issue Axon II with Maxbotix EZ1 sonar
« Reply #1 on: February 23, 2016, 11:46:51 PM »
Sounds odd.  Just to check a few things... which pin(s) specifically are you using?  Do you have a large number of other devices attached to your Axon II?
I

Offline SasounetTopic starter

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Re: Hardware issue Axon II with Maxbotix EZ1 sonar
« Reply #2 on: February 24, 2016, 11:39:50 AM »
Sounds odd.  Just to check a few things... which pin(s) specifically are you using?  Do you have a large number of other devices attached to your Axon II?

The current project has the following attached to the Axon II:

Two servos on slot B5 and B6
The EZ1 sonar on ADC#3 (but I tried ADC#1 and ADC#6 with the same result)
The signal pin of A0 (and ground) is attached to a stepper motor driver that needs only a pulse to rotate a step

The servos and stepper motor works perfectly. For the stepper, the program output a pulse of 10ms on the A0 pin. (Nothing is attached to the A0 5V pin).

Obviously I used the "AN" output pin on the sonar connected to the ADC signal input pin of the ADC header. I also connected the 5V and ground  from the sonar to the appropriate pins on ADC#3 (The usual 3 pins connector)

Finally I am 90% that the sonar displayed the same behavior when there was only one servo connected. But that was a long time ago so I am not 100% sure.

François

 


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