You can build a hygrometer yourself. As? Two ideas: First, you could make a cone hygrometer. This is easy to build yourself. This simple hygrometer indicates if the humidity is dry or humid. This does not allow slight changes and precise measurements.
Nevertheless, it is interesting to see how the pin works as a humidity sensor. The costs are very low. In addition to the pine cone, you need a wooden stick as a pointer, cardboard, glue, and a plate on which the pin is glued. Instructions for the construction of this hygrometer can be found below. To illustrate humidity, the development of a pin hygrometer is ideal for children who are in elementary school.
On the other hand, you could also build a hair hygrometer yourself. This is a bit more challenging to make. The costs are too low. You need a 10-15 cm long hair or sheep’s wool, one wooden board, two thin nails, one straw, soap, and a felt-tip pen. Also, you will need a hygrometer to calibrate your assembled hair hygrometer. The corresponding blueprint can be found below.
A digital/electronic hygrometer is much more challenging to build by yourself because you mainly need the electronic components.
Instructions: Build a pin hygrometer yourself
A pin hygrometer is not hard to build by yourself. The moisture meter is a pine cone. How does this work? The scales of the pine cone open in dry air and close in the humid air. Pine cones can be found in the forest – logically where pine trees are. The pin should be intact and as straight as possible. Also, this should not be too small in the middle of the pin-attach a rod. This serves as a pointer. This is, for example, a thin wooden stick, such as a toothpick.
Now you only need one surface, which serves as simple scale graduation. You could take a piece of cardboard for that. At the top of the cardboard, write the word “wet” so that the pointer points to the word “damp” as the shed scales close. Since you are likely to assemble the spigot hygrometer in a dry environment, the sheds of the spigot will be open. In this pointer position, the pointer should point to the word “dry.” Write the word “dry” there. To make sure that your cone hygrometer is stable and transportable, you still need a solid surface; Again, cardboard is sufficient. For example, a wooden surface looks more attractive. Let your creativity run wild.
In summary, you need the following materials :
- Pine cones (moisture meter)
- Wooden stick (pointer)
- Cardboard (scale graduation)
- Glue (best superglue)
- The base plate (on which the pin hygrometer stands)
If you have all the materials, you can start building the spigot hygrometer.
- Glue the pin as straight as possible to the base plate.
- The wooden stick that acts as a pointer must be glued to the pine cone. Find an opening in the middle of the pin.
- Put a few drops of glue in the opening.
- Insert the wooden stick into the hole in which the glue is.
- Wait a moment until the glue has dried, and the wooden stick is tight.
- Label the cardboard with the words “wet and dry” so that the pointer points to the word “wet” when the scales are closed. And the pointer to the word “dry” indicates when the levels are open.
- Glue the cardboard to the base plate behind the pin
Would you like to try out your new cone hygrometer right now? No problem. Take a spray bottle of water and spray your spigot hygrometer. After a while, the scales of the pin will close so that the pointer is almost vertical and points to the word “wet.”
The pin hygrometer must not be exposed to rain directly. Roofing is recommended. With the building instructions below, you can make a hair hygrometer.
Instructions: Build your hair hygrometer
In contrast to the pin hygrometer, the hair hygrometer does not use the pin as a moisture meter, but rather a hair. How can the humidity be measured with hair?
- Hair expands in the presence of moisture and
- dryness causes hair to contract.
This principle is used in the hair hygrometer – even on the available analog hygrometers with real hair and synthetic hair. The hair should be 10-15cm long for the construction of the hair hygrometer. If you have shorter hair, do not want to take your hair, or do not get that long hair from anyone else, you can also make a wool thread as an alternative.
For the construction manual, you need the following materials :
- Wooden board (about 20x30cm). Alternative: cardboard
- 10-15 cm long hair. Alternative: wool thread
- Two thin nails. Alternative: 2 pins
- Screwdriver / Hammer
- Straw (as a pointer)
- Soap (to clean the hair)
- Felt pen (to label the scale)
- A digital or analog hygrometer (to calibrate the hair hygrometer)
If you have all the materials, you can start building the hair hygrometer. While they are working, dry air humidity is recommended (below 50% relative humidity).
- The hair must be fat-free and clean. To do this, wash the hair with soap. Then let it dry.
- Insert a nail 2 cm from the edge of the straw. The tip of the nail must come out on the other side.
- Take the wooden board and lay it across.
- Prick the nail with the straw in the upper left corner of the board. The top edge is about 5 km away, and the left side about 2 cm. The nail may only be drilled so far in the wood that the straw is still freely movable.
- Drill the second nail 10 cm below the first nail. Just drill it into the wood so far that the pin sticks out a bit.
- Turn the straw so that the longer piece points to the right.
- Glue one end of hair about 7mm to the left of the screw on the straw with superglue.
- Place the board vertically or hang it on a wall. The board must hang or stand precisely vertical. If necessary, use a spirit level.
- Attach the other half of the hair to the lower nail so that the straw is pointing to the right and is precisely vertical.
Take your digital or analog hygrometer. If the analog hygrometer has not been calibrated for over half a year, you should first calibrate it. Place the hygrometer next to the hair hygrometer. Wait until the humidity of your hygrometer is up to date. The displayed value of the hygrometer is now also the current value of the hair hygrometer.
Now you can write down the value next to the straw on the right with a felt-tip marker on the board. As it becomes moister, the hair expands. The straw is sinking. Look again at your hygrometer and note the current value next to the end of the straw on the right. With this method, you can record several benefits on the board. Your hair hygrometer is now ready for use.