A college project that I'm setting up requires a Tweet-a-watt and another XBee that measures current/voltage output from a Solar panel array that is in DC. I'm using a sensor that steps down the DC values to something that the XBee ADC can handle. I would then normalize the values on the receiver end. Questions:
- For the DC voltage/sensor Xbee, do I solder up the Xbee adapter like that for the tweet-a-watt transmitter or that of the receiver?
- Can I just hook up the sensor to the ADC on the Xbee and see the data on the receiver along with the tweet-a-watt data? Guessing that I will have to develop some Python for the DC readings.
I looked around the forums and could not find a similar question. I just wanted to be sure before I assemble the 2nd adapter board. Excuse me if its already out there.
BTW, the Tweet-a-watt is working and logging the data correctly .I was going ask for help finding an alternative to the Google Powermeter since they shelved it ... Found Energylogger and it works great http://www.miloslick.com/EnergyLogger.html.
Thanks.
LJ
Xbee Adapter Question
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- adafruit_support_bill
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Re: Xbee Adapter Question
You would build it up as a transmitter & connect your signal to the XBee ADC. Assuming you have scaled the signal to safe ADC levels it should work pretty much like the Tweet-A-Watt transmitter.
- tinkeringtech
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- Joined: Wed Nov 23, 2011 10:08 pm
Re: Xbee Adapter Question
I'm going to use the same setup as recommended. However, would using the 4 AA batteries to supply power be the correct way to power the Xbee? I just eliminated the circuitry for the 5V~ coming from the Kill-a-watt.adafruit_support wrote:You would build it up as a transmitter & connect your signal to the XBee ADC. Assuming you have scaled the signal to safe ADC levels it should work pretty much like the Tweet-A-Watt transmitter.
Also, would the default Python for the Tweet-a-watt correctly parse the packets coming from the DC sensor?
Any special X-CTU configs needed for the DC sensor Xbee?
Thank you for all your help!
- adafruit_support_bill
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Re: Xbee Adapter Question
The XBee is a 3.3v device & the regulator on the adapter is a low-dropout type. You really don't need 4xAAs to drive it.
If you configure and hook up everything just like the TAW, the python should be able to parse the raw analog values. Scaling it to the correct engineering units is up to you.
If you configure and hook up everything just like the TAW, the python should be able to parse the raw analog values. Scaling it to the correct engineering units is up to you.
- tinkeringtech
- Posts: 98
- Joined: Wed Nov 23, 2011 10:08 pm
Re: Xbee Adapter Question
So you are recommending 2 AA's as the regulator will ensure that the 3.3V is maintained? This Xbee is not in a TAW, so it needs some source of power. Kinda new to regulators. Trying to understand it. Thanks.You really don't need 4xAAs to drive it
- adafruit_support_bill
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- Joined: Sat Feb 07, 2009 10:11 am
Re: Xbee Adapter Question
For the regulator to regulate, it needs an input voltage higher than the output voltage. For a "low-dropout" regulator as on the adapter, it doesn't need to be very much higher. 2xAA (alkaline) will give you 3v, so you would need 3xAA.
- tinkeringtech
- Posts: 98
- Joined: Wed Nov 23, 2011 10:08 pm
Re: Xbee Adapter Question
Thanks for your help. Here are some pictures from my build. The Kill-a-watt that I got from Amazon is a new version with a revised layout and IC. Also bear in mind that when you run the wires from the IC around the backside of the PCB, the wires can sometimes be wedged between the LCD screen and the screen contacts on the PCB. The screen was not lighting up initially and I thought my wiring was messed up. the TAW is an awesome device!
Please be positive and constructive with your questions and comments.