New Digital 9G Continuous Rotation Servo

stan74

Senior Member
I couldn't find one on ebay uk. Are the very recent? If you pulse them at <75 or >225 they just keep turning?
 

erco

Senior Member
Brand new, I'm beta testing for mfr Feetech. Will advise pulse range, building a bot now.
 

erco

Senior Member
Pulse range is 44-255. No motion below 44. Not sure if that 44 is a Picaxe thing or not.
 

erco

Senior Member
They aren't commonly or easily available anywhere yet. You can contact Feetech China to order, but shipping is slow yet pricey, and it takes a few iterations of email translation & haggling to get an order together. PM me if you want that contact info.

I'll be placing another small order in ~2 weeks if your needs aren't urgent.
 

jims

Senior Member
They aren't commonly or easily available anywhere yet. You can contact Feetech China to order, but shipping is slow yet pricey, and it takes a few iterations of email translation & haggling to get an order together. PM me if you want that contact info.

I'll be placing another small order in ~2 weeks if your needs aren't urgent.
Thanks for the offer erco....I'm not ready for them yet. JimS
 

stan74

Senior Member
Is this to fill a gap in the market,like why buy a servo and take it to bits? Indeed,not done that yet but why not take take all the electronics out and just use it as a geared motor instead of pulsing it or am I missing something?
 

erco

Senior Member
The big deal here is that Feetech is the only manufacturer of CR 9g servos, analog or digital. I have tried both, and the digital version is mechanically and electronically superior. Servos have a built-in high-current H-bridge motor controller and are ultra-simple to connect and control with a single pin of a Picaxe or other controller. Gearmotors require a a seperate H-bridge or motor controller, which are often quite large compared to a tiny 08M2 board and require 2 or more I/O pins per motor, one usually needs to be PWM.

An 08M2's four output pins (incl serial out pin C.0) can easily drive four servos (standard or CR) with full speed control. Using H-bridges, those four pins could only control two gearmotors through H-bridges. Since the 08M2 only has one PWM channel on pin C.2, so you would have bog down the processor to bit-bang PWM to speed control the second motor, or live with full on-full off.

One noteworthy exception is this motor controller board which makes gearmotors acts like servos, requiring just one control pin each. Coincidentally also by Feetech, which makes them my new best friend.
 

stan74

Senior Member
No one else makes micro servos,didn't know.Got my 1st to play with 3 months back and easy with picaxe servo function. Only £1, tiny but I got a few so hope removing the stop isn't too fiddly. Do I take the pot wiper off or bend it on 9g to continuous or just file the step on the cog?
 
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