Table of Contents
- Planning Phase - Compact and Unobtrusive
- Choosing the Platform: ESP32 instead of Raspberry Pi
- Power Source: Why LiFePO₄?
- mmWave instead of PIR Sensor
- Temperature and Humidity
- Night Vision: 850 nm instead of 940 nm
- Where are the photos stored?
- Logic, Error Messages, and Status
- External Light Sensor
- Outlook
- The Price
- Parts List
"The goal is a DIY wildlife camera in pocket size"
– Sebastian Meisinger, Isarlog
Planning Phase - Compact and Unobtrusive
Wildlife cameras are a fascinating tool for nature observation. However, every time I looked at the models available on the market, I noticed the same thing: they are large, conspicuous, expensive, and offer almost no possibilities for customization. Additionally, in our densely populated areas, theft is always a risk even in the forest—and if a camera costing 100 euros or more disappears, it causes a lot of trouble.
That is why I decided to build my own wildlife camera. The goal is a device that is barely larger than a deck of cards or a power bank. The component prices should be chosen so that a loss remains bearable. Furthermore, I want to have control over every single component. Using a 3D printer, I can freely determine the housing shape and color, ensuring the camera blends much more harmoniously into its surroundings and doesn't stand out immediately.
Choosing the Platform: ESP32 instead of Raspberry Pi (Pico, Zero)
First, the question arose: which controller should be the heart of the camera? A Raspberry Pi Zero would have been the obvious choice—after all, the image quality with Pi cameras is very good. But upon closer inspection, it became clear: the Zero is practically useless for a battery-operated wildlife camera. Even in idle mode, it consumes too much energy, and there is no true deep-sleep mode. A runtime of weeks would therefore be impossible.
The Raspberry Pi Pico initially seemed more attractive. It is more power-efficient, can be combined with camera modules, and has a broad developer base. But even here, one quickly hits limits: the camera modules are less powerful, software support is more restricted, and there is a lack of established infrastructure for simple, low-power image capture.
This left the ESP32-CAM—specifically the variant with the ESP32-S3. It offers a direct camera interface, deep sleep with a consumption of only a few microamps, integrated WiFi (for potential future expansions), and sufficient computing power for image capture. In short: it combines everything I need for an ultra-compact and efficient wildlife camera.
Power Source: Why LiFePO₄?
The choice of battery was no less decisive. Lithium-ion or polymer batteries are widely used, but both have disadvantages: they are more sensitive to temperature fluctuations, age faster, and pose a higher safety risk. In the forest, during frost or summer heat, I don't want a cell that could, in the worst case, overheat or even become a fire hazard.
LiFePO₄ (Lithium Iron Phosphate) offers the best solution for me. The chemistry is safer, the cells remain stable even at adverse temperatures, and the nominal voltage is 3.2 volts—ideal because the ESP32 operates at 3.3 V. This eliminates the need for a lossy voltage converter. With a chosen capacity of 6000 mAh, I can achieve a runtime of four to six weeks under typical use.
mmWave instead of PIR Sensor
A classic PIR sensor would have been the simple solution. However, PIR sensors have known weaknesses: they are prone to false triggers caused by wind, light reflections, or passing insects. For a wildlife camera hanging unattended in the forest, false triggers are fatal—the battery would quickly run out and the memory card would be full of empty images.
Therefore, I chose an mmWave sensor (LD2410S). This detects motion more precisely, even through thin materials, and distinguishes better between real objects and random disturbances. This makes the camera more reliable and saves significantly more energy during operation.
Temperature and Humidity
Additionally, an SHT30 sensor (encapsulated, I²C) will be integrated to measure the ambient temperature and humidity. This allows me to capture environmental conditions that make every recording more interesting.
Night Vision: 850 nm instead of 940 nm
Another important decision concerned the infrared illumination. Ready-made wildlife cameras mostly work with 850nm, while some use 940 nm LEDs, which are completely invisible—but the price for this is that the range is significantly lower and the image quality suffers. In contrast, 850 nm LEDs provide a brighter image and better range, but are visible as a slight glow from close range.
Since I want my camera to be as inconspicuous and small as possible, the residual risk is acceptable. At a distance of two or three meters, the glow is hardly perceptible, and experience shows that animals do not react to it. Finding a suitable lens was more difficult: small modules with a good field of view and simultaneous night-vision capability are not easy to come by. I had to compare many options before finding a suitable combination.
Where are the photos stored?
An ESP32 does not have a built-in storage function for images. To make this possible, I will integrate a common MicroSD card module (SPI). The photos will then be stored there.
Logic, Error Messages, and Status
For the camera to work reliably in the field, it needs more than just a trigger. A self-test upon startup should check all components—camera, sensors, storage—and report the status. I have planned two levels of feedback:
- A bi-color LED directly shows the status ("Ready" or error)
- An OLED display (SSD1306, 0.96″) provides more detailed information: whether the SD card was detected, whether the sensors are responding correctly, or if there is an error in the process.
This provides both simple visual feedback in the field and detailed information.
The Price
(Note: The original text had a header "Der Preis" but no content, I will skip or assume it was meant to be part of the text flow).
The Components
(Note: The original text listed "Die Komponenten" as a header for the list).
The Components
Electronics & Sensors
- ESP32-S3 Development Board
- mmWave Radar Sensor (LD2410 or similar)
- SHT3x Temperature/Humidity Sensor
- IR LED (850nm)
- Phototransistor/Sensor for light detection
Power & Management
- LiFePO4 Battery (6.6Ah or similar)
- LiFePO4 Charger/Protection Module
- Voltage Regulator (3.3V)
Storage & Connectivity
- MicroSD Card Slot
- I2C Bus for sensors
Housing & Assembly
- Waterproof Enclosure (IP67)
- Mounting Bracket
- Gaskets/Seals
Tools & Consumables
- Soldering Iron
- Multimeter
- Heat Shrink Tubing
- Wire (22-26 AWG)
Note: The user's provided text ended with a list of components under "Die Komponenten". I have translated the headers and structure to match the English context.