⑴A motor and a battery. Use cardboard to cut a fan blade, then connect the motor with wires
Battery (don't touch the wires with your hands), then the electric fan will be turned on. ready
p>⑵ Make a pinhole camera
Method:
Pinhole camera
A pinhole imager can be made depending on the model. principle of pinhole imaging. You can see clear images on its screen. If you install a photosensitive film on the screen, you can also take clear photos, but this requires a "shutter" and a device. negative. In addition, the waterproof requirements are more stringent than ordinary small-hole imagers.
The structure of the pinhole camera is shown in Figure 10.6-l. The body is made entirely of horse manure paper and is divided into two parts: the front cover and the rear cover.
Production method
Drawon the horse manure according to the dimensions in Figures 10.6-2, 10.6-3, 10.6-4 (δ is the thickness of the horse manure paper) On the paper, cut along the solid lines of each image, then use a knife to gently cut along the dotted lines, but do not cut through it, so that a straight edge can form when folding. Then paint both sides of each piece black.
Fold the cut outer layer of the front cover (Figure 10.6-2) 90° along the dotted lines to form a five-sided paper box (the small tab is glued to the outside of the box). Stick the tape. Then stick a piece of black 120 film backing paper to the side with the round hole and use a needle to pierce a small hole in the backing paper in the center of the hole, with a diameter of approximately 0.4mm (a no. 12). the sewing needle has a diameter of approximately 0.4 mm). As shown in Figure 10.6-1, a slot pOur paper is placed on the side of the small hole, and a strip of cardboard is inserted into the paper slot, which can not only act as a shutter, but also keep the small hole clean.
Fold the cut inner layer of the front cover (Figure 10.6-3) 90° along the dotted lines to form a square tube, and glue the interface (the uvula is glued inside square tube). . Then fold the trapezoidal tabs at the end with the gap into a paper frame, align the reinforcement frame (Figure 10.6-4) with the gap and glue them together. Cut a paper frame from cardboard according to the size of the reinforcement frame, align the notches and attach it to the reinforcement frame, and use strips of tape to stick the paper frame to the square tube at the outside. A paper frame is formed between. the reinforcement frame and the cardboard slot, the film can be loaded or removed from the side thanks to the notch is designedto facilitate loading and unloading of the film. After the inner layer is completed, it should be glued with the outer layer, that is, bend each trapezoidal tab on the other end of the square tube 90° along the dotted line, apply glue, align the gaps and insert the outer layer. layer while inserting the inner and outer layers on each side. Insert a piece of horse manure paper in between to ensure that the space between the inner and outer layers on each side is the same after the front end of the inner layer is firmly stuck. On the side with the round hole on the outer layer, remove the inserted piece of horse manure paper and the front cover is ready.
As for the production of the back cover, except the side width is 80＋26mm and there are no holes on the bottom, everything else is the same as the productction of the outer layer of the front cover. Refer to the expansion diagram of the outer layer of the front cover and the corresponding dimensions for cutting.
How to use
1. pinholeThe image distance is about 64mm, and the light transmission aperture is 0.4mm, so the aperture is also fixed. Experiments show that the aperture number is about 160. When the brightness of the photographed scene is different, the exposure time can only be used to adjust it. Since the aperture number of a general camera is about 22, the exposure time of aperture 160 cannot be found, so it can be determined based on the ratio of aperture time. exposure equal to the square of the aperture ratio (i.e. t1:t2 = (F1:F2)2). For example, when photographing a certain scene, the exposure time is 1/30 of a second with an aperture of 16, then the tempps exposure should be 3.3 seconds with a pinhole camera with an aperture of 160. The optimal exposure time should also be determined experimentally.
2. The method of framing when taking photos with a pinhole camera is shown in Figure 10.6-5. Place one eye near the middle of one side and “aim” toward both ends of the opposite side. Then the part caught in this angle is the scope of ingestion. Moving the distance between the camera and the photographed scene can change the size of the image.
3. Exposure: Choose the scene to photograph, calculate the exposure time, remove the cardboard covering the small hole and close it at the planned exposure time.
4. Loading and unloading films: A single piece of 60×60 mm2 film is often not easy to purchase, so large films must be cut. Loading, unloading and cutting of the film must be carried out in alight-tight darkroom.
Remarks
1. Be careful during manufacturing and there should be no light leaks.
2. The pinhole should be round and the edges should be smooth.
3. Since the exposure time is long, it is preferable to photograph still lifes.
⑶Materials: needle, candle, wire, cold water, transparent plastic bottle, iron cone, thin wooden stick
Wrap the sewing needle with thread iron, then put it on fire and burn it red, then immediately put it in cold water to cool. It must be remembered that when diving, the needle must face north and south, so that it can become a small magnetic needle. Also, you have to be careful not to burn it!
Cut the mouth of the plastic bottle, use an iron punch to punch a hole in the center of the bottom, then tie one end of the thin wire to the milihad the small magnetic needle, then pass the thread through the hole. Turn the plastic bottle over so that the small magnetic needle hangs in the middle of the bottle. Slowly stop the small compass needle. At this time, you will find that one end of the small compass needle is pointing south and the other end is pointing north.
⑷Small technology production - water changer for aquarium
1. Production idea: The lifespan of goldfish is actually very long, but due to improper feeding, such as movement during the process of changing the water in the aquarium If the goldfish is scared by its large size, the lifespan of the goldfish will be shortened. How to minimize movement when changing water? I thought about making an aquarium water changer using the siphon principle.
2. Equipment: an empty drink bottle, a flexible hose of approximately 2 meterss long (inner diameter approximately 7 mm) and all-purpose glue.
3. Production process: Drill two holes (slightly smaller than the tube) on the cover of the beverage bottle, cut the soft rubber tube into ends of 130cm and 70cm, respectively insert one centimeter into the cover, and use Paste seal with universal glue and tighten the bottle cap.
4.: Insert one end of the long tube into the bottom of the aquarium, squeeze the bottle to expel some of the air and pinch the mouth of the short tube tightly, then loosen the bottle to allow water to enter the bottle, and finally loosen the short tube and the aquarium water will flow out.
Note: The height of the drink bottle and the liquid level of the water outlet should be lower than the liquid level of the aquarium.
5. Principle: siphon principle
6. Advantages: It can minimize disruptiontion of the fish and the bottom of the aquarium can be filled with fish excrement without removing the fish. The water is sucked out.
I have a new household electric fan motor and want to turn it into a generator. How should I change it?
. You can remove the motor wires from the toy and wrap 300-400 turns of 0.02mm diameter wire around each magnetic pole. The toy motor has 3 magnetic poles. The method of winding the wires is clearly visible before removing the wires. As with the original winding method, the contacts can be soldered with a soldering iron.
1. Turning a household electric fan motor into a generator requires no modification (the running capacitor cannot be removed as long as the driving force is used to turn the rotor at 1500). rpm, the output will be output to both ends of the winding 220V power supplymain.
2. The rotor has been replaced with a permanent magnet, so there is no need to use a running capacitor. The original stator winding does not need to be modified. The two terminals of the main winding are used as. exits; If the rotor is replaced with a 2-pole permanent magnet, magnetic, the driving force must be used to rotate the rotor at 3000 rpm.
Extended information
Notes:
1. View random file
The motor fan is installed. random Instructions for use, product certificates, electrical circuit diagrams and packing lists should be checked, and components should be checked.
2. Look at the appearance of the motor fan
Check carefully to see if the motor fan grille and fan blades are visibly deformed. The fan blades should rotate raquickly and flexibly and do not always have to stop in the same position.
3. Look at the starting performance
Starting performance is an important quality indicator of the motor fan. Upon inspection, at slow speed and 85% of the rated voltage of the power supply, the motor fan should be able to start from stop and operate normally. The shorter the time it takes for the motor fan to return to normal operation. improve engine fan starting performance.
4. Check the speed regulation performance
After power on, there should be no abnormal noise in the mechanical transmission part of the fan. When the electric fan operates at high, medium or low speed, the motor and fan blades should be stable, with low vibration and low noise. The fan of the wordeur should shake and stop quickly without interruption, stagnation or instability.
5. Check for electrical leakage
After the motor fan is turned on, if you feel numbness and electricity when you touch it with your hand, use a test pen to test. The test pen also has a light display, which can determine whether the case is leaking or not.
Reference materials:
Baidu Encyclopedia-Electric fan motor