(Mostly) 3D Printed Hands-free Sanitizer Dispenser

Introduction: (Mostly) 3D Printed Hands-free Sanitizer Dispenser

About: I'm a self employed programmer/web developer who builds electronic gadgets mostly for fun but aiming to, one day, start doing it for a living.

Hello there,
This project comes in two flavours: a wall mounted version and a free standing version. The wall mounted version is sturdier and requires less PLA, while the free standing one is more versatile (can be carried around) but requires a wooden base to be screwed to.

The 3D printed parts are designed so that they can be printed with a 0.8mm nozzle for faster printing and since no supports are needed, post processing is minimal. The unit's body is made from a 40mm PVC tube while the internal shaft is a 20mm tube.

This design comes with two options for the bottle holding tray, to allow for bottle of 85x70mm footprint or 66x66mm footprint.

Supplies

Wall Mounted Version

Countersunk Screws
2x M3x8
2x M4x10
4x M4x16
4x M4x20

Hex (Allen Key) Head Screws
4x M4x12
4x M4x16
2x M4x25
1x M4x50

Lock Nuts
1x M4

Regular Nuts
4x M4

Self Tapping Screws
4x M5x50
1x M3.5x12

Round Head Screws
1x M3x25

Other
4x Wall Anchors
1x Rubber Band
2x 3mm diameter eye terminal
1x 40mm diameter PVC tube (1000mm length)
1x 20mm diameter PVC tube (1080mm length)

Free Standing Version

Countersunk Screws
2x M3x8
2x M4x10
4x M4x16
8x M4x20

Hex (Allen Key) Head Screws
4x M4x12
4x M4x25
1x M4x50

Lock Nuts
1x M4

Regular Nuts
2x M4

Self Tapping Screws
6x M3x20
1x M3.5x12

Round Head Screws
1x M3x25

Other
250x250x25mm Square Wooden Platform
1x Rubber Band
2x 3mm diameter eye terminal
1x 40mm diameter PVC tube (1000mm length)
1x 20mm diameter PVC tube (1080mm length)

Step 1: Print the Parts for the Variant You Want

All the parts can be printed with 0.8mm nozzle for quicker printing, but they can, of course, be printed with a regular 0.4mm nozzle. The layer height I used was 0.32mm, the wall thickness can be set to 2.4mm, the top and bottom walls were set to 19.2mm and the infill was set to 25%. For the Pedal_Plate.stl part, I set the top wall to zero so that the infill (grid) could show through and form a pattern for the pedal. This step is totally optional.

You can download the parts from here:

https://cults3d.com/en/3d-model/tool/hand-free-sanitizer-dispenser


For the wall mounted version print the following parts:

Holder_Clamp.stl
Holder_Stand.stl
Holder_Tray_66x66.stl or Holder_Tray_85x70.stl
MarkingTool.stl
Pedal_Left.stl
Pedal_Plate.stl
Pedal_Right.stl
Stand_U.stl
TopLever.stl
Tube_Base.stl
Tube_Cap_with_slot.stl
2 x WallMountBracketBack_16mm_offset.stl
2 x WallMountBracketFront.stl

For the free standing version, print the following:

Holder_Clamp.stl
Holder_Stand.stl
Holder_Tray_66x66.stl or Holder_Tray_85x70.stl
Pedal_Left.stl
Pedal_Plate.stl
Pedal_Right.stl
Stand_Left.stl
Stand_Right.stl
Stand_Clamp_Left.stl

Stand_Clamp_Right.stl
TopLever.stl
Tube_Base.stl
Tube_Cap_with_slot.stl

Step 2: Prepare the PVC Tubing

  1. Cut the 40mm diameter PVC tube to a length of 1 metre.
  2. Cut the 20mm diameter tube to a length of 1080mm.
  3. Drill 3 aligned holes along the 20mm tube as follows (it is important that the holes are perfectly aligned):
    3mm hole 15mm from the top
    6mm hole 200mm from the top
    4mm hole 10mm from the bottom edge
  4. Drill a 2mm hole that is 90 degrees from the plane of the other 3 and 56mm away from the top edge.
  5. Screw the M3.5x12 self tapping screw inside the latter hole. This screw will act as a guide to prevent the shaft from twisting.

Step 3: Mount the Elastic Band

  1. Insert one end of the elastic band inside one of the eye terminals using some thin wire and crimp the elastic securely.
  2. Thread the elastic through the 6mm hole in the 20mm PVC tube.
  3. Crimp the other eye terminal to the other end of the elastic.
  4. Slide the Tube_Cap_with_slot part onto the shaft from the side of the elastic, making sure the guide screw is in the slot in the printed part.
  5. Attach the elastic to the Tube_Cap_with_slot part using two M3x8 countersunk screws. Make sure they are not threaded in too far because that would stop the shaft from moving freely. Conversely, make sure the screw heads are flush with the rounded edge of the Tube_Cap_with_slot part so the part can later on slide into the 40mm PVC tube.

Step 4: Build the Pedal

  1. Fit the Pedal_Plate part to the Pedal_Left and Pedal_Right parts using four M4x16 countersunk screws.
  2. Attach the pedal to the Tube_Base using two M4x25 allen key screws. You might want to fit washer between the pedal parts and the base part.

Step 5: Mount the Body

  1. Insert the 40mm diameter PVC tube inside the circular slot in the Tube_Base part
  2. Fit the Tube_Cap_with_slot part (complete with shaft and elastic) on the other end of the 40mm PVC tube and slide the far edge of the shaft through the whole in the Tube_Base part
  3. Secure the shaft to the pedal using a M4x50 allen key screw and a lock nut as shown in the diagram. Note that for clarity, the diagram does not include the base and the body.

You should now be able to pull the pedal down and it should pull the shaft with it. The elastic should be able to pull the shaft back once the pedal is released.

Step 6: Bottle Tray

  1. Slide in the Holder_Clamp through the top edge of the body.
  2. Use four M4x12 allen key screws (round head work just as good) to secure the Holder_Stand part in place. The same screws can be used to tighten the clamp and adjust the height of the tray to fit various bottles.
  3. Attach the tray of your choice to the Holder_stand.
  4. Attach the TopLever part to the top edge of the shaft and secure with a M3x25 round head screw.

Step 7: Mount Unit to a Wall

For the free standing version go to step 8

  1. Attach the Stand_U part to the base using four M4x20 countersunk screws. This is used to help set the proper distance from the body to the ground.
  2. Use the MarkingTool to make two sets of two holes on the wall where the unit is to be mounted. The vertical position of the mounting brackets is not very strict but they need to be perfectly aligned vertically. It is important that the upper bracket is below the bottle holding clamp, otherwise the bottle would not fit.
  3. Fasten the two WallMountBracketBack_16mm_offset parts to the wall using M5x50 self tapping screws and wall anchors.
  4. Align the unit body to the mounting brackets and secure in place using M4 nuts (that should slide snuggly into the bracket back), M4x16 bolts and the two printed WallMountBracketFront parts.

Step 8: Stand Alone Version

  1. Attach the Stand_Left and Stand_Right parts to the Tube_Base and Stand_Clamp_Back parts using eight M4x20 countersunk screws.
  2. Secure the stand firmly to the body using Stand_Clamp_Front part that is in turn secured in place using M4x25 bolts and M4 nuts.
  3. Tie the whole unit to the wooden block using six M3x20 self tapping screws.
The wooden platform is ideally pushed all the way back to a wall prevent it from sliding backwards when the unit is being utilized. Personally I still prefer the wall mounted version which is less wobbly, but some scenarios do not allow for the unit to be tied to a wall.

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