[Video] Soldering a Limit Switch Isolator
May 23, 2020
https://www.youtube.com/watch?v=_18urPHrtA4
GRBL PWM Inverter Circuit
May 25, 2019
Here is another quick circuit – this time a GRBL PWM inverter circuit showing how to invert a PWM circuit with only three components. This works great to invert the PWM signal out of GRBL to driver a laser.
PWM Inverter Circuit
As a use example, PWM_In would come from the Spindle Speed output of a GRBLDuino CNC controller and be inverted on PWM`_Out to drive a laser with inverted logic requirements.
GRBL Relay Driver Circuit
November 23, 2018
Here is a quick relay driver circuit showing how to drive a relay from a microcontroller – specifically, one of my GRBLDuino products.
Microcontroller Relay Driver Circuit
The circuit as shown is for a spindle control application but the circuit remains the same for any other use. 5V and GND are self explanatory. SPINEN is the signal coming out of the microcontroller and typically 0v DC or 5v DC. Microcontoller outputs can only switch a few mA before damage occurs, but this circuit allows the transistor Q1 to take the load and switch as much as it is rated.
To create a spindle control relay on GRBLDuino products, SPINEN connects to the Sp EN terminal block (the side labeled +). GND is connected to the other side of this same terminal block. 5V must be connected to a 5v source – the simplest way is to use a wire with a Dupont plug to connect to the high side of the Lim. H/L header.
Here are more GRBLDuino posts!
GRBLDuino Shield CNC Controller
December 26, 2017 1 Comment
Over the past few days I’ve been designing a Arduino Uno CNC controller shield.
My requirements were pretty simple:
- GRBL 1.1 compatible
- Pin compatible with Pololu DRV8825 drivers
- User replaceable stepper motor drivers
- Screw terminals for connections
- E-Stop, Abort, Hold, and Resume buttons
- Probe connection
- Spindle PWM control
- User selectable 4th axis function (clone or separate)
- No SMD packages in the first version
Arduino CNC shields are pretty easy to find (and shockingly cheap) but not many are compatible with the changes in GRBL 1.1. I didn’t want a product that was out of date before I even purchased it.
My design is loosely based on the Protoneer Arduino CNC Shield. I fully support the purchase of the Protoneer product but it is hard to get in the US – available only from his eBay store.