Power relay
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Sure thats one way of doing it and I think asking David to consider some sort of interface to radio switched plugs/alexa etc. could be a great addition. But I'm just considering simple M80 for on and M81 for off setup. I have 3 machines running duet board now so a simple solution is what I'm after. I have a power monitor running to the bench for all my printers it is interesting I agree.
If powering the duet from external 5v should we use the 5v & GND pins in the PS_ON header? Or can plugging in a usb charger/adaptor to the usb port suffice long term?
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You can feed power via the USB port or the external 5V connector (the one with the PS_ON pin), it makes no difference.
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Thank you.
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Share the results and diagrams if works. I'm thinking on use a similirar relay board with ps_on pins of the duet to fire the camera button and makes timelapses
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I'm still none the wiser as to how best to connect it. It seems some of these relay modules can accept a high or low signal, so set to low, I would expect you can ground the IN pin on the relay to the PS_ON pin on the duet to trigger it. For those relay modules which only accept a high signal then if PS_ON goes to ground when M80 is sent, I think it might be best to use something like a logic inverter to reverse the signal. https://www.ebay.co.uk/itm/LOGIC-SINGLE-INVERTER-GATE-5SC70-Part-SN74LVC1GU04DCKT/351615798176?epid=1339373369&hash=item51ddef4ba0:g:QM8AAOxy8HlSa77O
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If you choose a relay module with an optically isolated input, then it will hopefully have + and - control input terminals separate from the power supply terminals. In which case you can connect the input terminals to +3.3V or +3V and PS_ON.
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To use it as a camera trigger, I need to execute m80 and followed by m81. What interval would I have if I put them one below the other in the gcode?
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More than a microsecond, but possibly less than a millisecond.
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I can't tell if that is a joke or not. I will read about gcode waits and try to trigger the camera without the duet first
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Okay so I've settled on this one:
So to make this work, I would hook up +5v from the duet to both VCC and CH1 pins, then GND to PS_ON? -
No. Please post a photo of the back of the board with better lighting and focus, so that I can see the PCB traces clearly.
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The traces still are not very clear. But I think that CH1 and GND are the input signal, connected to the input of the opto coupler through a series resistor, while VCC and RGND provide power to the relay. If that's the case, connect VCC to +5V and RGND to ground. Connect GND to the Duet PS_ON output, and connect CH1 to either +5V or +3.3V.
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Okay thanks David. I'll have a play with it on the bench before connecting it to a duet board.
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Okay so it did end up working as I had suggested originally, I spoke to the vendor who said to ignore RGND and use VCC, GND, CH1 pins. In fact it did not seem to matter whether PS_ON is connected to GND or RGND so I presume they are tied. So connecting VCC and CH1 tied to +5v on expansion connector and then GND to PS_ON switches the relay on M80, and off on M81.
Nice bright LED too if you are going to put it under a cover of some sort it will shine through. Mine is going to live under the PSU end cover which keeps small fingers off the 240v wiring.
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Why dont connect the 5v/CH1 to the 5v on ps_on header?
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Because and it took me a few minutes to work this out yesterday, its a 5v input pin, not 5v output! There is a diode on it.
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Ok ok. Then 5v/CH1 go in any 5v output and gnd to ps_on.
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By any I presume it will have to be either the 5v output from your 5v power source for the duet board, or from the board itself with the ext-5v jumper attached. Otherwise the relay wouldn't have a ground.
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So soldered a link across CH1 and VCC, so I only need two wires. Works great. One thing I did notice, when I send an M81, the console reports a Warning: VIN under-voltage event (X.Xv) .
Not really a problem, but maybe the under voltage monitor routine should be shutdown on an M81 since obviously, the voltage is going to drop if you disconnect the PSU. The restarted on an M80? Perhaps it serves as a useful marker in the log to show when it shut off maybe?
So now using in start gcode
M80 ; PSU ONThen in end gcode
M109 S50 ; lower hotend temp to below glass transition temp
M116 ; wait for temps to stabilise (so PSU does not shut off whilst hotend is hot)
M140 S0 ; turn off bed temperature
M84 ; disable motors
M81 ; PSU offThis allows the hotend to get down below glass transition for any filament.