Nightvision equipment allows you to see in low light conditions by amplifying ambient light. While commercial systems can be expensive, you can build your own basic nightvision setup from common electronic parts for under $100.
Understanding Nightvision and How it Works
Before building your own system, it helps to understand the components and working principles behind nightvision.
Nightvision works by capturing and amplifying ambient light that is invisible to the naked eye. This allows you to see even in very low light conditions like darkness.
The main components in nightvision devices are:
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Image intensifier tube - This tube captures ambient light and amplifies it thousands of times via an electrical process. The intensified image is displayed on a phosphor screen inside the tube.
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Objective lens - This lens gathers ambient light and focuses it on the image intensifier tube. Larger diameter lenses can collect more light.
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Eyepiece - This is a small magnifying lens that lets you view the phosphor screen image. It makes the image appear larger and easier to see.
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Power supply - Provides electrical power to the image intensifier tube. Can be a battery pack or external power source.
With this overview of how nightvision works, let's look at building a DIY system.
Sourcing the Required Components
The main parts you need for a DIY nightvision setup are:
- Image intensifier tube
- Objective lens
- Eyepiece lens
- Power supply
- Housing to mount the components
Image intensifier tubes can be purchased online from electronics and surplus stores. Gen 1 and Gen 2 tubes provide good performance at affordable costs for DIY projects. Expect to pay $50 and up based on image resolution and sensitivity.
For the objective lens, look for a large diameter (25mm or more) convex or bi-convex lens. Surplus stores carry multi-element camera lenses that work well for around $20.
Use a small eyepiece lens in the 10-25mm range. Small magnifying lenses for electronics projects are inexpensive at $5-10.
Power supplies can be a simple 9V battery holder with clip leads to connect to the image tube. Rechargeable 9V lithium batteries provide longer runtime. Use a regulated 9V-12V DC adapter for extended use.
For the housing, plastic piping, wood boxes or metal tins can be adapted to mount the components. PVC pipes make lightweight housings, and common electrical boxes work as well.
Shopping surplus electronics and hobby stores will uncover most of the parts you need at reasonable costs.
Constructing the Housing
The housing holds and protects the components and blocks out ambient light. Small plastic or metal boxes with lids make ideal housings.
If using a plastic housing, spray paint the interior with flat black paint to minimize internal reflections. Cut holes to mount the objective lens and eyepiece, and drill a hole for the power supply leads.
Use tape or glue to fix the image intensifier tube and objective lens in place. Mount the eyepiece lens behind the tube's output window. Seal any light gaps with tape or silicone sealant.
Leave room for the power supply and wiring inside the housing. Install an on/off switch to control power to the image tube.
Connecting and Powering the System
The image intensifier tube has two electrical connections - one for the cathode (negative) and one for the anode (positive).
Refer to the tube datasheet for the specific voltage requirements, which is typically around 3,000V at very low current.
Use clip leads to connect the 9V battery pack to the image tube's cathode and anode. This portable setup works for short term use.
For extended usage, power the tube from a 9-12V DC adapter through a voltage booster circuit to provide 3,000V or more. Make sure polarities match the tube's requirements.
Using and Testing the Nightvision System
To use your DIY nightvision system, turn off room lights and power it on in darkness. Peer through the eyepiece and slowly scan across the dark room.
Adjust the objective lens focus until the image becomes sharp. Move the eyepiece back and forth until the image is clearest.
Start testing at night with streetlights or moonlight coming in through windows. Try different lighting conditions from near-total darkness to dusk.
Your basic nightvision system amplifies ambient light thousands of times, enabling you to see in darkness! With some experimentation and refinements, you can build an effective nightvision setup on a budget using common electronic parts and surplus components.