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i/o on a series one xbee

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Forgive me if I am asking a stupid question, but this is going to be my first venture into this type of project.

I am looking to retrofit my wired tig welding pedal to be wireless. This is a very simple device. There is a momentary switch that closes when you begin to rock the pedal. This tells the power supply to turn on welding current. Along with that is a potentiometer that is used as a voltage divider that changes as you rock the pedal.

If I am correct, all I would need is the switched and analog inputs on the transmitter (pedal), and a relay and digital pot on the receiver (welder) side.

My question is, I have come across some resources that say you can do basic i/o functions with a standard xbee 1. Others say that I would need to go to a programmable xbee. Since this is my first project, and by many accounts a series one is easier to setup, I would like to stick with a standard series one if possible.

With the simple nature of the project I would think that I could get away with just a series one, but would like some input from more knowledgeable people before I jump the gun.

I am trying to keep this as small as possible, so I would rather not add a teensy or equivalent if I can get away with one piece of hardware.

Thank you for any help
asked Apr 17 in RF Solutions and XBee by bgood New to the Community (0 points)

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1 Answer

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Bgood,

Yes, the XBee 802.15.4 modules can perform a basic DIO line pass function. You can also do a ADC conversion with them. To do a ADC to DAC you do need to add some additional components as described at https://www.digi.com/support/knowledge-base/converting-the-xbee-pwm-to-an-analog-voltage-for-d

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answered Apr 17 by mvut Veteran of the Digi Community (12,313 points)
Perhaps if I were to use an op amp with a 1:3 ratio and the xbee has 3.3V I could directly use the pwm to get my "divided voltage."

As I thought about it more, if I use the 10 volt system from the welding power supply, with a 3.3v regulator, the voltage from the pwm, 1:3 op amp output would just get connected to the wiper terminal of my welding power supply.

Is my line of thinking incorrect there?
Thank you for your response. Forgive my ignorance, as this is my first venture into any ic projects. I am trying to figure it out as I go.

I am not entirely sure what you are suggesting with your response.

My first guess is that using the pwm output and low pass filter I could control a digital pot with that analog voltage. The thing I am missing here is that with my very limited knowledge of ic's I dont understand how this would help me with controlling the post. Arent pots controlled by serial? Perhaps this analog voltage is part of serial control? Like I said, i am trying to figure things out by reading, and dont yet fully grasp serial control

My second though is that since the link you sent me mentions that it will reproduce whatever voltage is sent to it from the other xbee, and since the pot is being used as a voltage splitter i could just have it produce a voltage over 2 wires and omit the pot. This wouldn't work for me, as the welder is a 0-10v system, far too high for the xbee.

Thank you for your help
Bgood,

The schematic I am referring you to takes the PWM output of the XBee and concerts it to an analog voltage out which would then give you ADC in on one side and DAC out.

Yes, you will need to use a  voltage divider to get the 10V level down to the 1.2V level that the XBee requires.


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