Using an xbee on Teensy3 without an adapter

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nlecaude

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Hello,
I'd like to use an Xbee with a Teensy 3 without the adapter as I am short on space.
Am I understanding correctly that I can simply connect pin 1 of the xbee to 3.3v, pins 2 and 3 to one of the uart and pin 10 to ground ? Do I need anything else ?
 
nlecaude said:
Hello,
I'd like to use an Xbee with a Teensy 3 without the adapter as I am short on space.
Am I understanding correctly that I can simply connect pin 1 of the xbee to 3.3v, pins 2 and 3 to one of the uart and pin 10 to ground ? Do I need anything else ?
Click to expand...

Yes that will do it, the only thing you need to worry about is that some xbee models (pro) can use more than the 100mA while transmitting than teensy 3.3V can supply. Even the series 1 xbee use 50-70mA, that leaves not much for anything else you connect to the 3.3V line. You also can connect one of the teensy digital pins to pin 9 on the xbee to do "pin sleep" but requires you to modify the default xbee firmware.
 
Thanks, as this will be used with octows2811 i don't think I'll need the 3.3v line for anything else. I'm using the series 1 pro.
Now I need to see if I can find xbee radios without the male headers as I was thinking about soldering wires directly and couple it to the teensy using molex microfit connectors.
 
nlecaude said:
Do I need anything else ?
Click to expand...

Not unless you intend on updating the firmware.

I'd monitor the system voltage during transmissions and if the Teensy power supply cannot handle the transients, I would consider attaching a larger input and output capacitor to help. Ladyada solved her XBee transmission problems inside the Tweet-a-Watt with a 10,000uF (!!!) 6.3V capacitor. However, the Teensy offers a lot more oomph! in the voltage regulator department so you may be OK. If not, start by adding something small like 10uF capacitors until the power supply stabilizes. To prevent bad things from happening during power-downs, be sure to have more capacitance upstream of the power supply than on the regulated side.

FWIW, my Xbee 'shield' only features a 4.7uF capacitor - but that's because the spec sheet for the voltage regulator I'm using( MCP1825) claims 500mA of capacity - i.e. 5x the Teensy 3 and requests no more than 22uF being attached on the regulated side.
 
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Xbee pro model consumes more power... But as said, transmitting times are short, like 1 msec or less.
 
Hmm I see that the model I want to use (the rpsma variant) can consume up to 340ma in transmit mode, from what I understand the regulator on the Teensy is only 3.3v ? So It would be better to use my main 5v power source with my own 3.3v regulator ?
 
Yes, I'd use a separate regulator. Don't need a heat sink since transmission duty cycle is so low.
 
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