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I have a couple of XBEE S2 with RPSMA antenna I'm using the xbee explorer(with arduino) and XBIB development board with X-CTU on a PC.

if I drive the arduino from the USB,,, it works... not really fine, but there's some data beeing sent and received.

However, as soon an i move to batteries (http://www.batteryspace.com/li-ion18500cylindricalrechargeablecell37v1400mah518wh---ullisted.aspx) NOTHING works! the xbee xplorer's tx blinks but i receive nothing on the other end. the arduino's XBEE doesn't even receive anything.

i have other components connected and they are ALL working fine except for the XBEE. I know that the program is still there and the power is OK. what can be wrong!

here's a simple schematic

schematic

simulate this circuit – Schematic created using CircuitLab

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  • \$\begingroup\$ Please add a schematic of how your circuit is wired up. At first glance it appears that some ground connection is missing in the battery operated arrangement. \$\endgroup\$ – Anindo Ghosh May 20 '13 at 2:08
  • \$\begingroup\$ I would do that but can you plz give me a simple way to do the schematic? I'm sure that the grounds are OK. the power light is ON. the tx light is blinking, other sensors are working fine. \$\endgroup\$ – himura May 20 '13 at 5:33
  • \$\begingroup\$ Edit your question, then press Ctrl-M to open the Circuit Lab schematic editor integrated into this site, with your cursor at the place you want the schematic to appear. Create the schematic in Circuit Lab, save and insert. \$\endgroup\$ – Anindo Ghosh May 20 '13 at 5:50
  • \$\begingroup\$ done @Anindo Ghosh \$\endgroup\$ – himura May 20 '13 at 10:17
  • \$\begingroup\$ i'm done @AnindoGhosh \$\endgroup\$ – himura May 22 '13 at 17:39
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Assumption

Assuming you use this XBEE shield, when you check the circuit diagram, you'll notice that there is voltage regulator MC33269.

Cause of malfunction

Although MC33269 is an Low Drop regulator, it is spec'd for 1 ~ 1.35V dropout voltage. This means that if you supply 3.7V from your battery an extra 1 ~ 1.35V will be dropped for the XBEE, resulting in 2.4 ~2.7V supply voltage. Depending on which XBEE datasheet I check, the minimum required voltage ranges from 2.1 ~ 2.8V or even 3V for the pro version referenced in the first example.

What to do

In other words carefully check the power supply voltages with a voltmeter against the correct datasheets for all modules, XBEE, Arduino and your other sensors.

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