So I want to control 4 servos from some distance, will this be possible with such board? Can’t add images here, so uploaded them to Imgur: Imgur: The magic of the Internet
Welcome… yes
Is it better to power ESP module (board?) from 3.3 or directly from 5V?
Also: what this link for?
looks like you got it boss! some other XIAO modules have other communications capabilities
i didnt see you already had a circuitboard designed
i would power thru the battery pad on the bottom… as you say… you may want to provide a separate power for the needs of the servo and only the controller at 3v3… some have problems powering at the 5v but some dont… so just know that
My pleasure I’m all about the PCB…
Hi there,
NICE work, but it may not work … 
One or two comments I would make is you don’t have any other IO available with all the N/C’s. I would run a few to a header (set of holes at least). for Indicators, limit switches, Safety features after-thoughts, new features future proof… I see a power “ON” Indicator but No run LED or status?
The PCB doesn’t use the chips battery pads? (power pins)
I see plenty of filtering Caps but NO decoupling ?
I know one or 6 is required for ESP to be stable. better research that reference design.
You may need a set of line drivers between the servo’s and the board outputs. (ringing on the cables long distances), etc.
Power supply better be clean, clean. ripple wise.
Those are my .025
HTH
GL 
PJ 
from the wiki ,
Power Pins
- 5V - This is 5v out from the USB port. You can also use this as a voltage input but you must have some sort of diode (schottky, signal, power) between your external power source and this pin with anode to battery, cathode to 5V pin.
- 3V3 - This is the regulated output from the onboard regulator. You can draw 700mA
- GND - Power/data/signal ground
Strapping Pins
According to the chip manual of ESP32C3, GPIO2, GPIO8 and GPIO9 in the chip are Strapping Pins, the high and low level configurations of these pins may allow the chip to enter into different Boot modes, please pay attention to this point when you use these pins, otherwise it may prevent your XIAO from uploading or executing the program all the time.
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3V3 - This is the regulated output from the onboard regulator. You can draw 700mA
I’m confused. Is this output only for Vin? I thought I could supply current through this pin to the ESP.
The PCB doesn’t use the chips battery pads? (power pins)
No, it doesn’t.
but NO decoupling ?
I assumed the decoupling was handled on the XIAO board itself. If I add decoupling capacitors near Vin, what difference would it make given the distance between the chip and the capacitors? They need to be within a millimeter or so for optimal performance. All filtering capacitors are based on the recommended layouts of the corresponding buck converters (except the 1000µF, which is for the SG90 servos).
Regarding the strapping pins, since the XIAO board works when powered solely through USB, I assumed these pins were internally connected to 3V3. Is that correct?
i guess we gonna have to do some power experiments to figgure this out… but my sudgetion is to use a XIAO Grove Xepansion board
Hi there,
Correct, USB or Battery pads,. for power for some applications a diode can be used with the %V pin to supply the power however caution is taken when connecting a USB with it configured this way.
Again read over the wiki, and have a look at the schematic.
Decoupling is key for no noise on the servo signals under load. how smooth the servos work will be a function of how clean the power is to them as well as the control signal. Look at some of the servo threads on here and see what others have done.
Filtering looks sufficient add a few more decoupling caps by the VCC and near the Xiao and near the power leads to servos. is my .02
HTH
GL PJ
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Would you recommend powering XIAO board from 3V3 or 5V pin? If 5V, then I can remove AMS1117 circuit, but I’m not sure if this a right thing to do.
Hi there,
Many have used the 5Volt pin and extra diode.
so I would choose that if not using battery pads
HTH
GL 
PJ