Pendant with Air Assist

#1 · January 30, 2019, 3:31 am

I'm planning on building a pendant for stop, pause, go, reset with air assist. First question is I'm having a hard time reading the silkscreen. Is there a documented pinout for the IO pins. Secondly is there an output for air assist that only turns on air assist when cutting. I plan on using an air solenoid.

Tim

#2 · February 20, 2019, 5:19 am

For connecting air assist relay Paul pointed me to cpumap.h to make a possible firmware change, but in reading through the file I noticed that the coolant is connected to Arduino pin 3.

// Define flood and mist coolant enable output pins.

#define COOLANT_FLOOD_DDR   DDRC
#define COOLANT_FLOOD_PORT PORTC
#define COOLANT_FLOOD_BIT   3 // Uno Analog Pin 3
#define COOLANT_MIST_DDR   DDRC
#define COOLANT_MIST_PORT PORTC
#define COOLANT_MIST_BIT   4 // Uno Analog Pin 3

I scoped the pin out and it goes to 5V when M8 is sent and goes back to 0V when M9 is sent. M8 is coolant on and M9 is coolant off (M7 disables) from the grbl documentation. Lightburn sets these by default. I'm still learning on Arduino things, and was surprised to find that in this case an Analog IN pin was used as an output.

I ordered one of these:

https://www.amazon.com/DZS-Elec-Channel-Isolation-Tolerant/dp/B0721M34CM/ref=sr_1_11_sspa?ie=UTF8&qid=1550257891&sr=8-11-spons&keywords=arduino+relay+module+high+level+control&psc=1

This is a special relay that enables high or low trigger. We need a high trigger and most of the Arduino relays work only low trigger, so this one is the best option and enables both air assist as well as turning on/off my ventilation system.

Bottom line is it's a simple trigger connected to pin 3 that switches the relay and no FW updates are needed.

I'll post when I get it wired up.

Tim

Paul has reacted to this post.

#3 · August 23, 2019, 11:24 pm

Hey Tim,

Is this pin broken out on the board anywhere? I've probed around on the headers a bit but no such luck. Unfortunately my eyes aren't that great for detail work and I don't like my chances of successfully probing the right pin on the MCU without shorting it to another 😐

#4 · August 24, 2019, 2:01 am

It's Uno Analog In Pin 3, it is labeled on the shield with the ribbon cable pointed up it's on the right, 3rd pin down.

Tim

#5 · August 24, 2019, 8:50 am

Ah I see, sorry I was thinking this was on the Mini Gerbil, not the Arduino Shield.

Thanks for replying anyways ????????

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