Free digital outputs on Rambo board?  

Re: Free digital outputs on Rambo board?

So... I took a brief look at this a while back. I'm not sure I found a definitive answer then, and I'm not sure I correctly remember what I found, but for what it's worth, here's what I remember... 😉

There aren't any obvious spare outputs on the Mini RAMBO. There are spare *inputs* -- the board has inputs for both min and max limit switches on all three axes, but the i3 only has min switches, leaving the max inputs free. I *think* what I read was that the unused max inputs can only be used as inputs, but the min inputs are hooked to pins on the controller that can also be used as outputs (I didn't check this with the controller spec). If this is true, then it would be possible to move one or more min switch to connect to max inputs, change some constants in the firmware so it would expect that, and do something possibly easy and possibly more complicated to the firmware to drive the min "inputs" as outputs in response to gcodes.

So maybe possible, but probably a bit of work. The RAMBO is an open-source design, so documentation is available. Schematics are at http://reprap.org/wiki/MiniRambo .

If you try this, let us know how it works out!

Re: Free digital outputs on Rambo board?

All Arduino digital pins can be configured for either input or output.

The MAX end-stop sockets are available as are the pins connected to the P3 header, plus a few other headers on the board.

Pins.h is the file to look at to see what is available.

Peter

Re: Free digital outputs on Rambo board?

Thanks for the correction, Peter, that's good to know.

Re: Free digital outputs on Rambo board?

Good to hear there are unused pins!
But as far as I can see, there is no option to control them via gcode?
That would mean to create a custom firmware and modify it every time a new one comes out 🙁

Re: Free digital outputs on Rambo board?

That would mean to create a custom firmware and modify it every time a new one comes out 🙁

Exactly. And if you go down that route, you won't be the first...

Peter

Re: Free digital outputs on Rambo board?

Hi all,

I have to bring this up again.
I checked the 3.0.10 firmware and it still has M42 command enabled for these pins

0, 1, X_STEP_PIN, X_DIR_PIN, X_ENABLE_PIN, X_MIN_PIN, X_MAX_PIN, Y_STEP_PIN, Y_DIR_PIN, Y_ENABLE_PIN, Y_MIN_PIN, Y_MAX_PIN, Z_STEP_PIN, Z_DIR_PIN, Z_ENABLE_PIN, Z_MIN_PIN, Z_MAX_PIN, PS_ON_PIN, \
HEATER_BED_PIN, FAN_PIN, \
_E0_PINS _E1_PINS _E2_PINS \
analogInputToDigitalPin(TEMP_0_PIN), analogInputToDigitalPin(TEMP_1_PIN), analogInputToDigitalPin(TEMP_2_PIN), analogInputToDigitalPin(TEMP_BED_PIN)

PJR, you mentioned the MAX end stop pins are available, are these EVERY max pins like
X_MAX_PIN,
Y_MAX_PIN,
Z_MAX_PIN
or are there others from the above list that are unsused?

thanks!

Re: Free digital outputs on Rambo board?

If you want to control lights or anything else, you could tap into the buzzer which is just a PWM player.

Then use an arduino nano to read the PWM and control your mosfets or anything else using GCODE to modulate the PWM.

Re: Free digital outputs on Rambo board?

Thanks, but that leaves me with another device to program 🙂