How to convert push buttons to on/off switch?

Thread Starter

Gordito_WV

Joined May 31, 2023
9
Recently purchased some Grabo Pro-Lifter portable electric vacuum lifters to be used with a lift system we are making to lift panels from a hoist in our cabinet shop, similar to the photo below. Instead having to manually push the on/off buttons or using a cable actuator as seen in the photo, I would like to have an on/off switch on the handle to turn both Grabo lifters on and off. I assume it's possible, but I'm not sure how to do it. Any help would be appreciated.

Grabo specs:
Model/SKU GRABO PRO-LIFTER 20 / GP-1Li-FB
Battery 14.8VDC 2600mAh Li-ion
Rated Power 16W
Charger Input Voltage 100-240VAC 50/60Hz
Battery Charging Time ~2hrs
Non-Stop Running Time (Full Charge) 1.5hrs
Running Cycles (On Full Charge) 900 ON-OFF cycles of 10 seconds
Stand-by Mode (Charge Hold) 30 days
Pump Service Life 100000+ ON-OFF cycles / 800+ hrs continuous


Screenshot 2023-05-30 133758.png1685541450531.png
 

Alec_t

Joined Sep 17, 2013
13,793
I would like to have an on/off switch on the handle to turn both Grabo lifters on and off.
Welcome to AAC!
From what I understand from those pics and the video there are three on/off functions per lifter: (1) the 'power on/off' switch (presumably a latching push-on-push-off one), (2) the pump 'motor' starter (the motor seemingly turns off under internal control) and (3) the 'seal' release. Is that correct?
Methinks you would need to know the lifter's internal wiring for those functions, to be able to convert to "an on/off switch" on the handle.
 

Thread Starter

Gordito_WV

Joined May 31, 2023
9
Correct, there is a power on/off switch as well as the green push button, which activates the vacuum, and the red button, which releases the pressure. It would be fine to manually switch the power on and off because we would only do this once a day. I would like to somehow enable to vacuum & vacuum release some type of "on/off" switch because we will do this multiple times throughout the day.
 

Alec_t

Joined Sep 17, 2013
13,793
Unless you can tolerate some electro-mechanical add-on to physically push those buttons you will need to reverse-engineer the circuitry. Have you had a peek inside a lifter to see how the buttons are wired?
 

MisterBill2

Joined Jan 23, 2018
15,698
If all of the button functions are only electrical then an extension cable with remote buttons could be the way to go. Non- momentary switches for a battery powered device is asking for some grief. But without an electrical circuit of at least the buttons any suggestions are totally guesses.
 

MisterBill2

Joined Jan 23, 2018
15,698
"Switching it on and off once a day " will assure that the battery life is shortened and the devices do not provide satisfactory service for very long. From the photos in post #7 it appears that the vacuum release is a mechanical function, not an electrical function. That will make any alterations rather challenging.
What is the intended benefit of the change requested?? And in the lead photo I see three of them, and a bracket to utilize three at a time. So would three of these be used in unison???
 

Thread Starter

Gordito_WV

Joined May 31, 2023
9
"Switching it on and off once a day " will assure that the battery life is shortened and the devices do not provide satisfactory service for very long. From the photos in post #7 it appears that the vacuum release is a mechanical function, not an electrical function. That will make any alterations rather challenging.
What is the intended benefit of the change requested?? And in the lead photo I see three of them, and a bracket to utilize three at a time. So would three of these be used in unison???
Do you suggest to turn the device off after every use?

The idea is to have a "switch" or some way to remotely activate or deactivate the vacuum so the machine operator wouldn't have to manually press the buttons each time he wants to load a panel onto the machine, which would make the process quicker and more efficient.
 

MrChips

Joined Oct 2, 2009
29,246
I don't understand what you are trying to do.
As purchased, the Grabo is manually operated. Green button starts the suction motor. Red button releases suction.
How do you want to use the Grabo that is different from manual operation?
 

Alec_t

Joined Sep 17, 2013
13,793
So you're just wanting to replace 3 presses of buttons with 1 press of a switch?
From the photos in post #7 it appears that the vacuum release is a mechanical function, not an electrical function.
I agree. There may be an associated switch (with those red and black wires attached?) which informs an MCU that the release mechanism has been activated.
 

Thread Starter

Gordito_WV

Joined May 31, 2023
9
I don't understand what you are trying to do.
As purchased, the Grabo is manually operated. Green button starts the suction motor. Red button releases suction.
How do you want to use the Grabo that is different from manual operation?
Look at the photo in my original post. We are making a similar device that holds multiple Grabos in order to use as a panel lift that will be connected to a hoist, which is mounted to a jib crane. So we would use this device, go to the panel we want to load, lower the unit to the panel, activate the Grabos suction. Raise the panel using the hoist remote. Move the panel to the CNC router. Deactivate the suction. Cut panel. Machine auto-unloads the cut parts. Rinse & repeat.

We can manually activate and deactivate the Grabo suction, but will have to reach over half the width of a 5' panel (3/4" melamine mostly) for each Grabo everytime we load a panel and we cut 30-40 panels a day. I'm trying to make this a simpler process with some type of remote switch, but it's not looking like that will happen.
 

Thread Starter

Gordito_WV

Joined May 31, 2023
9
So you're just wanting to replace 3 presses of buttons with 1 press of a switch?

I agree. There may be an associated switch (with those red and black wires attached?) which informs an MCU that the release mechanism has been activated.
That was my original hope, but not looking possible. It doesn't really matter how they are turned on or off as long as we can do that "remotely", which would be less than 3' from the Grabos. If the mechanical rout is the only way to do that then fine. I just wanted to ask the experts opinions if it could be done electronically.
 

MrChips

Joined Oct 2, 2009
29,246
Ok, understood.
For remote operation, you can go wired or wireless. Do you have a preference?
Would you be willing to accept very long cables?
 

MrChips

Joined Oct 2, 2009
29,246
I'm fine either way
Wired is easier to implement. Wireless is more convenient for the user but requires additional RF circuitry.
I believe this is very doable and relatively simple. It would require a cable with two pairs of twisted cable going to each unit.
I suppose that you want multiple units to be activated at the same time.
 

MisterBill2

Joined Jan 23, 2018
15,698
Can you confirm if they are actually electrical operators or other means?
Looking at the one photo of the opened device, tghe green button looks like an electrical switch, while the red button operates a push-rod, which I am guessing opens a vacuum release valve, which is sort of visible in the one photo.
So the power switching on and off can be done by a three-pole switch, one for each of the devices. Likewise the green button can be replaced by a momentary three pole switch. That is just a bit of wiring. Operating the red vacuum release function button would be more complex, as it would require using three linear motion cables to mechanically press the three buttons. But as that motion will not need to be precise and perfectly synchronized, it is entirely able to be done. An arrangement using something like bike handbrake cable should be good enough.
An alternative would have been to use commercially available vacuum gripper cups and a three-way manual valve, along with a mains powered vacuum pump with a tank and a vacuum sensor switch. Then the whole thing would have been much simpler.
 
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