G2S Servo Carriage Clip by wbrucem

Last crawled date: 3 years ago

I have been using Painless360's carriage clip for a while, which has been a bit of a love/hate relationship. I love when it works as intended, but I hate forgetting to remove it for the start of the next print. I'm eliminating the hate by converting the clip into a servo controlled device.
This is designed for a generic 9g servo motor. I'm running an MKS Gen controller board in my printer, which includes g-code addressable servo ports, so operating the servo will be pretty straight forward for me. For those of you still running the stock GT2560, sorry, no servo ports there. However, I have included a simple Arduino sketch to operate the servo, based upon a signal from one of the end-stop switches. I tested the Arduino solution using a Pro Mini, the code should be compatible across virtually the entire Arduino family. (You can see my Arduino breadboard operating in one of the photos, the blue wire comes from the end-stop switch.)
The lower latch part is easily removable, in case you need to disable the latch, e.g. during calibration, etc.
Update: I have discovered potential servo ports on the GT2560! The X_MIN and Y_MIN inputs are unused on this printer. Through the magic of Arduino, these ports can be reassigned to function as outputs to control servos.
As can be seen in the last photo, the board actually has 3 connections under the 2-pin endstop sockets, the extra one being +5v, exactly what is needed to power a servo. Be careful, the layout of these pins does not match the standard servo pinout (+5v should be in the middle).
Convert the X_MIN socket to 3-pins and connect it to the servo. In Repetier Firmware, enable Servo Support (Features tab) and assign the "Servo 0" pin as "X min endstop". (In the Mechanics tab, set the "X min" pin to "Disabled/No Pin".) Use the following G-code to control the latch servo:

M340 P0 S1500 ; Unlatch carriage (P0 = Servo 0, S1500 = mid position)
M340 P0 S2300 ; Enable carriage latch

(Marlin firmware may offer similar servo features, you'll have to work that out for yourself. I don't use Marlin anymore.)
While you're in there, convert the Y_MIN socket as well. I have something in the works which will use a second servo... 8)