World Smallest Solenoid Engine

Hey everyone! Today, I’m super excited to share something truly special with you my world's smallest solenoid engine. It’s an incredibly tiny yet fully functional engine that works just like a real one, but on a miniature scale. It uses electromagnetic force to move a piston, creating rotational motion just like the engines in cars, but way smaller and more precise.

This little project took a lot of trial and error, but the result is absolutely worth it. If you're into engines, solenoids, or just cool tech, you’re going to love this! Let me walk you through how I built it step by step, so you can see how everything fits together to make this tiny Engine.

Thinker CAD design: https://www.tinkercad.com/things/3jCdgilWbS4-solenoid-engine i have designed the sol

these are some tools and materials are used for crafting the solenoid engine. not mentioned all we can see in detailed in the below steps

Tools and Materials

Materials:

1. acrylic sheet (3*2cm a broken plank)x1
2. roofing hook (6mm)x1
3. Small neodymium magnets (4*4mm)x4
4. Copper wire enamel (33 SWG,5meters)x4
5. PCB board (2*1.5mm)x1
6. Power source (5v , 2A )x1
7. Volleyball valve (one piece)x1
8. adhesives(feviquick)x5
9. Nails (1 mm)x2
10. Aluminum sheet (a aluminum empty bottle)x1

Tools:

1. Soldering iron
2. Precision drill
3. Wire cutter/stripper
4. Multimeter
5. Scientific calculator
6. Sand paper
7. marker
8. scale & pencil

a waste acrylic sheet (transparent plastic) is used here to make a body frame of the solenoid engine. the piece is i made in this step is a base part it is a rectangular shape, the length is 3cm and breath is 2cm. sand the edges to make perfect rectangular. the material is Transparent, lightweight, and easy to cut.

. Ensure they’re perpendicular to the base and parallel to each other. Sand all edges to remove sharp corners.

1. Here we calculated the height of the crank shaft from the base (IMG 2.4)
2. Draw the rectangular shape (2x1.5CM) on the acrylic sheet with the marker (IMG 2.1)
3. cut the rectangular frame and sand the frame edges for smoother
4. Draw the points 9*10 mm and point out the cross mark. (IMG 2.5)
5. this frame give the support to the crank shaft and drill the holes.(IMG 2.7).
6. Before making the holes make sure that the height of the drill bit and the cross mark is same.(IMG 2.6 & 2.7)
7. after made the holes place frame perpendicular with respect to the base frame (IMG 2.9)
8. To secure the frames to the base using strong adhesive (IMG2.9)

using acrylic, ensure cutouts allow easy monitoring of internal components.

The side frame is 3mm*2mm stick it to the base, these frames are used to enclose the side part of engine it protected the internal parts from mechanical damage and supports the crank shaft holder.

1. Draw a side frame outline (rectangular 3*1.5).
2. Smooth the edges with sandpaper.

Ensure they are perpendicular to the base for proper alignment.

This step is simple use a small steel valve to avoiding the heat and friction. The diameter of hallow is slightly grater than crank shaft.

The combination of steel for strength and the valve’s smooth interior ensures low friction for rotating parts like a crankshaft.

Inserting the hallow steel tube to avoiding the expansion of holes while crank shaft is rotating

1. Cut the Volleyball valve length of 3mm. (IMG 4.1, 4.2)
2. A soldering iron allows precise fitting of the valve into the steel tube.(IMG 4.3, 4.6 & 4.7)
3. Make sure that it is aligned properly other wise the the crank would not run smoothly.

Here the roofing hook is used to make a crank shaft. this technique i got from the random scrolling a short videos from youtube is about a guy is making a dead crab into robotic armed crab where the arm and legs are moved by this type of crank shaft. Then i searched for a metal soft rod and I get this roofing hook from my storeroom.

1. firstly, I cut off the hook threaded side (IMG 5.1,5.2,5.3). then i took the soft side (IMG 5.4)
2. After that the hook soft side is rounded by a paper exactly it fit in it. this step is the purpose to measure circumference of hook (IMG 5.5)
3. we get the circumference is 21.5MM (i.e. 2.15CM) by measuring the width of the paper (IMG 5.6).
4. Then the paper is further divided into 4 units (IMG 5.7). because we use here 4 Solenoid, we have to determine how much circumference is occupy on crank shaft by each solenoid

each one unit = circumference/4 = 21.5/4 = 5.375 MM

21.5 mm = circumference

4 = no of solenoid

5.375 mm = for each unit

we can see these steps clearly in below video link. ( Untitled video - Made with Clipchamp (4).mp4 )

5. when we done with calculation then draw the lines on paper (IMG 5.7,5.8)

6. stick the paper around the roofing hook. (IMG 5.9,5.10)

7. Cutoff the cross marked parts of the hook (IMG 5.11)

8.cut the hook into 3cm as marked end point on the paper (IMG 5.14). After that we can see hook converted into the crank shaft

make a centre hole on the crank shaft at corners and attach the nail for holding the crank shaft in the solenoid engine and also for coupling the fly wheel and wiper

1. Insert the crank shaft into the drill chuck (IMG6.1)
2. mark centre point with marker (GIF6.3)
3. drill the hole at both ends (6.4)
4. Place the nails into the holes use the material the thickness is same as radius of the crank shaft so we can make the nail straight to alignment centre of crank (IMG6.9)
5. Then soldering them.(IMG6.10)
6. cut the shaft as require (IMG 6.11), we see clearly in GIF
7. here we can see all lengths are mentioned in the last image in this step (IMG 6.14)

The solenoid cylinder is the hollow structure. Aluminum is an excellent choice for building the solenoid cylinder in our solenoid engine due to its lightweight, non-magnetic, and heat-resistant properties. Strong enough to withstand mechanical stresses during the engine's operation.

1. cut out the required amount of sheet from bottle (IMG
2. 
   

Design an Aluminum Solenoid Cylinder

1. Inner Diameter:
2. Ensure the inner diameter of the cylinder allows the magnet (piston) to move smoothly with minimal clearance (e.g., 0.5–1mm).
3. Length:
4. The cylinder should be slightly longer than the magnet (piston) stroke to full movement and prevent the piston from exiting the cylinder.
5. Surface Finish:
6. The interior surface must be smooth to reduce friction and wear on the piston.
7. Alignment:
8. The cylinder must be perfectly aligned with the solenoid coil for optimal performance

drill the holes on body frame to inserting the solenoid cylinders

the solenoid can fit and adjust by solering iron. this the best way to aligement the cylinder to the engine body

The connecting rods transfer motion from the pistons (magnets) to the crankshaft.

Measure the distance between the wrist pin end and crankshaft to determine the length of the connecting rods.

cut the extra of connecting rod.

It is a cylindrical rod that connects the piston (magnet) to the connecting rod in an engine.

Its primary function is to allow the piston to pivot and transmit force to the connecting rod during the engine's operation.

Using a neodymium magnet as the piston in your solenoid engine can enhance performance by leveraging its strong magnetic properties. This approach improves the interaction with the solenoid's magnetic field, making the engine more efficient.

Use a cylindrical or cylindrical-shaped neodymium magnet 4*4mm

the Use a cylindrical or disc-shaped neodymium magnet that fits snugly within the solenoid cylinder.

Wrist holder is 3mm*1.5mm*3mm as shown in ( IMG )

make the surface of the magnet as rough for strong bond between the magnet and Wrist holder

stick the wrist holder to the magnet (Piston)

make a hole for inserting the needle to hold the wrist pin on the magnet.

remove the sharp edges to free movement of the wrist pin in the

In this step we are going to assemble all the internal parts of the engine they are

1. piston (magnet)
2. wrist pin
3. crank shaft
4. Back frame

the main purpose is to connect the piston to the connecting rod

assemble the wrist pin in the wrist holder ( IMG 12.1)

cut the extra part of the needle

check whether the wrist pin is moving freely or not (IMG 12.5 and GIF)

attach the back frame to the engine and make sure the crank is rotating freely or not and then sick it by feviquick

The before wrapping the coil on the solenoid cylinder we must know the

Ensure the solenoid cylinder (core) is clean and smooth.

To Identify TDC in Solenoid Engine (IMG 13.1 &13.2)

1. Rotate the crankshaft slowly.
2. Observe the piston's movement within the cylinder.
3. When the piston reaches its highest point, then identified TDC.

This cylinder forms the core working area where the solenoid interacts with the piston.

after finding mark the either side to the TDC (top dead centre) for the wrapping the copper wire around the cylinder within the marked area. (IMG 13.3)

because under the marked area we have to produce the electromagnetic force to pull the magnet (piston)

Ensure the solenoid cylinder (core) is clean and smooth.

If required, wrap a thin layer of insulating tape around the core to prevent short circuits.(IMG13.5)

Now wrap the copper wire around the cylinder within the marked area. (IMG 13.7)

The copper wire is wrapped around 5meters for each solenoid. I dont know the exact turns if we need to know then we have to do calculation

it is a multilayer coil, the number of turns depends on the dimensions of the wire and the core, as well as the number of layers. Here’s a more detailed formula:

N = L/(πx(D+(n-1)xd)) = 5000/(3.141x(4+(10-1)x0.254))

N = 5000/19.744

N = 253.24 = 254 turns

all are mentioned in mm only

Where:

1. N =is the total number of turns.
2. L= is the length of the wire. ( 5mtrs = 5000mm)
3. π= is the constant pi (approximately = 3.14159).
4. D= is the diameter of the solenoid cylinder. (4mm)
5. n= is the number of layers. (approximately = 10 layer)
6. d=is the thickness of the wire. (diameter =0.254mm)

When calculating for multiple layers, you consider the increase in diameter as each layer is added. This formula essentially accounts for the expanding diameter as you lay each additional layer of wire.

The commutator component in a solenoid engine, responsible for controlling the timing of current flow to the solenoid coil. This ensures the magnetic field is generated at the precise moment to push or pull the piston, enabling the engine to operate efficiently. the speed is depends on applied voltage and current the minimum is 5 Volts and 2 amps

Rotating Contact Made of conductive materials like copper. Mounted on the crankshaft.

1. 
   
2. Ensure the PCB has holes for secure attachment to the engine frame.(IMG 14.2)
3. Design paths for electrical flow to match the commutation.(IMG 14.9)
4. Add solder pads or terminals for connecting the PCB to the solenoid. The connection is made as shown in the image (IMG 14.10)
5. Rotate the commutator manually to ensure smooth contact with the PCB pads.(GIF 14.8)
6. take a enamel copper wire and rem

Here we are added the fly wheel which is taken from the cutting machine gear box and attached to the shaft for the restore the force in fly wheel.

Functions of a Flywheel

1. Energy Storage:
2. Stores excess energy generated during the solenoid’s power stroke.
3. Energy Release:
4. Releases stored energy during the piston’s return stroke, stabilizing rotation.
5. Momentum Stabilization:
6. Reduces fluctuations in rotational speed, ensuring smooth operation.
7. Load Balancing:
8. Compensates for uneven power delivery from the solenoid by maintaining steady torque.

make sure the gear can be securely mounted and fits well with your solenoid engine's design

Connect the USB to the solenoid engine (IMG 16.2 & 16.3)

Now connect the USB to the 5V 2A = 10 watt Adapter

connect that adapter into the socket and Switch on.

Then Give a small push to the fly Wheel and it starts rotating ( GIF 16.6)

The speed of the engine is depends on the voltage level and current level. max is 12V and 2A

Finally we done the World Smallest Solenoid Engine

please give your opinion on this project, let me know in the comment.

Thank you 😊.