Giant Functioning Emergency Stop Button

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Introduction: Giant Functioning Emergency Stop Button

Emergency Stop (E-stop) buttons are a very important safety measure utilized to prevent catastrophic events from escalating. While these buttons are featured everywhere, a person is rarely put in an unfortunate position that requires the activation of one. Needless to say, these shiny buttons look very tempting and fun to use. For years we have been told to not push the red button... until now. This Instructables will outline how to assemble your very own GIANT e-stop button that actually works.

The end result of this project will yield a button that looks and performs like a traditional emergency stop button. While this is great for harmless projects, it should never be used to replace certified shutoffs.

Please be sure to watch the gifs that are included with most steps for assembly clarification.

Step 1: Parts

4 - Metal Badge Clips - Link

1 - Micro Limit Switch - Link

1 - 15x21x4mm Precision Ball Bearing - Link

1 - PCB Screw Terminal Block Connectors - Link

- M2 x 3 mm Brass Cylinder Knurled Insert Nuts - Link

- 2mm x 0.4mm x 6mm Phillips flat head screws

Step 2: 3D Printing

Everything was modeled, rendered, and animated using Fusion 360.

All parts were printed on the Creality Ender 3 pro using PLA with a 0.2mm layer height.

Due to the complex nature of the parts, enabling supports will yield the best result.

Step 3: Getting Started

First, start with the clip frame.

This 3d printed part mounts the clips in the designated slots to allow one direction travel. These clips will hold the button in the shutoff position when pressed.

The piece has 16 holes that are designated for the m2 threaded inserts. Half can be found on the sides of the and the rest on the bottom. Position the part with the tabs found inside the cylinder at the top. Using two screws per side, fashion the clips with the teeth facing upwards.

Step 4: Suspension

Next, it is time to assemble the spring suspension system. This will allow the button to return to its primed position.

The spring base has four holes on the bottom designated for heated inserts.

Insert one spring into each cylinder found on the part. Once the springs are in position, the spring lid can be lowered on top. This should allow for linear movement between the two parts with minimal friction.

When the assembly is deemed functional, press-fit a bearing into the center hole found on the spring lid.

Currently, this system is not securely attached together. With some movement, it is bound to fall apart. Once this frame is included in the final assembly, the pieces will be properly held in the correct position.

Step 5: Main Body Assembly

Using four screws, the tabs of the clip body can be attached to the bottom of the spring assembly.

When the two features are firmly secured, the camshaft can be press-fitted into the pre-installed bearing from below.

The bottom of the camshaft is egg-shaped by design. The lobe of the cam will toggle a limit switch on and off depending on the state of the button.

This assembly makes up the internal frame.

Step 6: Outer Shell

The next step in the process is to assemble the outer shell. While it is cosmetically enhanced, these parts are crucial to the success of the internal mechanism.

The button top had slots for 12 heated inserts to be installed. This number is twice the amount required for assembly. The holes will be intermittently used for both the inner and outer rings. In case of damage or aggravated strain, the other slots can be utilized to prolong the life of the part.

The outer cylinder can then be attached to the top using the four tabs found on the inner surface of the cylinder.

Step 7: Putting It All Together

Once the internal frame and outer shell are each assembled, it is time to combine the features. The frame can be slotted into the shell with the bearings and camshaft aligning with the cylindrical extrusion located on the base of the button top. The shaft can then be fastened into the top using two screws. This attachment will cause all pieces to be secured in their designated place.

Step 8: Electronics

As previously mentioned, a limit switch will be used to make the button functional. The switch will be positioned in alignment with the asymmetrical camshaft. When the camshaft is arranged at both the right height and angle it will be able to toggle the connected circuits.

The NO and NC circuits (found on the limit switch) are each wired to a block connector, creating an easy connection point to any circuit.

The electronics frame is designed to house both the limit switch and block terminals in acceptable locations. This frame is designed to be easily swapped or modified to suit project needs.

Step 9: Base

Once all of the components are assembled inside of the housing, the button can be attached to the base. First, attach the electronics frame using the designated holes found on the base. When the electronics are secure, the base itself can be attached using the screw holes aligned with the clip frame. This should allow the button enough travel to properly use the latching mechanism.

Step 10:

Attached are the STL files required for the project.

Everything was designed using the metric system.

It is important to note that there are two different versions for the base model.

Step 11: Cad Download

While I am hesitant to release the cad files for this project I understand that every printer is different and some file modifications are necessary. Please understand that my design process is somewhat chaotic and unorganized. I did my best to go through the parts and make everything as clear as possible. The file uploaded is for Fusion 360. Please reach out if you have any questions. I will try to be more responsive.

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    24 Comments

    0
    fred_dot_u
    fred_dot_u

    1 year ago

    I'm looking forward even more to seeing the CAD files. I printed all the parts, they look great. ABS with HIPS supports make for a stunningly clean under-surface. Unfortunately, every part that has to fit to another part is about a mm too large. The spring shafts won't insert into the spring tubes and the inner clip holder won't fit the outer cylinder. It might be less than a mm, but not-fitting is not-fitting. If I re-scale the part, the spacing goes out of kilter and everybody knows how important to keep things in kilter.

    0
    fred_dot_u
    fred_dot_u

    1 year ago

    Has anyone built this wonderful device? It's challenging to find affordable M2 flat head (countersunk) bolts. Would pan head or button head or cap head bolts work without interference?

    0
    WhyyNot
    WhyyNot

    Reply 1 year ago

    Hi Fred!
    I know those screws are not commonly used and typically hard to come by. I had several leftover from a project with super tight constraints that required those specifications which is why they were used here.
    You should have enough clearance to use either type of screw mentioned. The only place you will run into problems will be on the base component. The screw heads that attach the base to the rest of the body need to fit into holes with a 4.4mm diameter. The screws that were used to hold the electronics frame are countersunk to keep the surface flush. Anything else will cause an uneven surface. That being said, there is an easy workaround to this problem. You can simply extrude the base surface a little more to allow room for the alternate screw heads or you could simply add feet to the project (Furniture protectors work great).
    As discussed in another comment, I will be sharing the cad files soon to allow for modifications. It would probably be worth comparing the dimensions in cad with the bolts you are considering.
    I used https://www.boltdepot.com/ for my machine screws.

    0
    fred_dot_u
    fred_dot_u

    Reply 1 year ago

    Thanks for the reply. I have an account with bolt depot and mostly forgot I did. Pretty good price, better than the book seller people. I'm surprised you don't have the link in the text.
    It's good to hear you'll be sharing the files too. I'm not particularly capable when it comes to most of the CAD stuff, but I enjoy to see how they work.
    I'm working on a latching relay circuit (in my alleged mind) to see if I can increase the safe load capacity of the big button. Big power for big button!

    0
    jeanniel1
    jeanniel1

    1 year ago

    How fun! I teach CNC and laser cutting at a maker space and we start with Safety First - so this would have been fun to have on hand!

    0
    WhyyNot
    WhyyNot

    Reply 1 year ago

    It's definitely fun to play with! Those E-stop buttons were always so tempting to push.

    0
    jeanniel1
    jeanniel1

    Reply 1 year ago

    Oh, we've had to really push them at times and it's amazing how well it works! Heh heh heh. A couple of times when I was working in the machine shop on campus, we were shocked to have to push the Emergency Stop button, but it sure was a good lesson!

    0
    manicmonday
    manicmonday

    1 year ago

    What? No video of it actually in use? I'm appalled!!! No seriously you should include a video of it in use.

    0
    WhyyNot
    WhyyNot

    Reply 1 year ago

    You're definitely right! I will add a video/gif of it in action asap.
    Once the button is pushed into the locked position You have to twist it once to allow it to spring back up. I didn't have time to engineer a torsion spring into the system so a second twist will then be required to return everything to the starting position and engage the limit switch.

    0
    manicmonday
    manicmonday

    Reply 1 year ago

    That is good to know, but the main thing I was to have is perspective. Seeing a normal sized hand with the button will provide that.

    0
    DougL56
    DougL56

    Reply 1 year ago

    I second this! I can't even tell how it works. Are you supposed to twist it?

    0
    DanC289
    DanC289

    Reply 1 year ago

    The normal operation is to push the button which then latches until twisting Clockwise which releases the switch back to the original state.

    0
    MrErdreich
    MrErdreich

    1 year ago

    This is pretty cool and I plan to make one for my classroom, not for the machines though. Probably to turn my stereo on or off.

    Thanks for sharing!

    0
    WhyyNot
    WhyyNot

    Reply 1 year ago

    Great to hear! Let me know if you have any questions about the project.
    Depending on how you are planning to power on and off your stereo, it will be important to keep an eye on how much current is being passed through the limit switch suggested above. You may want to consider adding a relay circuit.

    0
    kmpres
    kmpres

    1 year ago

    Nice! I'm glad you said in your intro that this is a fun project and that it should not be used as a real emergency button. Those limit switches are designed to pass signal currents only, that is, not more than a few amps at low voltages. Any power circuit, even a small one, will fry them. Some on-off LEDs for demonstration purposes, though, would be ideal.

    0
    WhyyNot
    WhyyNot

    Reply 1 year ago

    Yes, although this is a really cool project I would not want this button to be the only thing standing between life and death. Sure it is probably better than some MacGyvered safety systems out there but it's not worth the risk when actually safety certified switches are already so cheap.
    The limit switches used in this project were targeted for simple low-risk microcontroller circuits (such as Arduino). If I wanted to use a higher current I planned to add a relay circuit. There are plenty of mounting places for this on the base. I know using a separate circuit isn't ideal but this project is more for show and tell. As I mentioned in the Instructable I tried to make this part of the project as customizable as possible. It should be very easy to create a custom part to hold any switch of your choosing.

    0
    ichfrissdich
    ichfrissdich

    Reply 1 year ago

    Many micro switches are designed for 250V 16A

    0
    kmpres
    kmpres

    Reply 1 year ago

    Most are rated at around 0.1A to 3A. Those salvaged from printers and other home mechanisms, as those appear to be, are usually in the 0.3A to 0.6A range. You can buy higher rated switches but they are hard to find and cost more.

    0
    ichfrissdich
    ichfrissdich

    Reply 1 year ago

    I don't know where you live but when I go to my local electronics store half of the switches they have are multiple amps capable

    0
    kmpres
    kmpres

    Reply 1 year ago

    I'm sure that's true, but I was specifically referring to the switches seen in the instructable. The author refers to them as limit switches and limit switches should only pass signals, not power. Also, the link he provides indicates that they are good for 5 amps, but I usually down-rate anything I buy on eBay and Amazon as one never knows if the Chinese manufacturer is being honest with his ratings.