OLED Display

The OLED connects to the Pi Zero over the I2C bus, too. It serves as an informational display to output details of the device's status and the recording process when setting up in the field. The screen is switched on along with the Pi Zero and switched off accordingly when the wildlife camera is idle.

To specifically trigger a photo, swipe your hand over the motion detector to see whether a new photo is taken and what timestamp it has. The recommended approach here is to check the test shot directly afterward to realign the camera, if necessary.

Battery and Charging Electronics

I used a lithium iron phosphate (LiFePO4) battery, which has a very low self-discharge rate and a good power-to-weight ratio. It doesn't suffer from a memory effect and works at low temperatures. All of this is ideal for a photo trap in the wild.

Although you can find chargers for these lithium batteries, you can equip existing charging modules with a protective circuit to limit their end of charging voltage to 3.6V. I used a solar power manager by DFRobot with connections for a solar module with 4V to 6V, an external charging option, and a battery connection. I also added a protection board mounted directly on the battery (Figure 4). The small battery management board offers deep discharge and short circuit protection in addition to overcharge detection.

Figure 4: The charging electronics include a battery with a protection circuit.

Conclusions

Because of the shutter lag caused by the power-saving mechanism, this wildlife camera is not suitable for capturing animals moving quickly through the focus area. However, experience has shown that only very few garden visitors are in such a hurry, which is why I think, after a period of use in my own garden, that this DIY model is up to the task. Because I regularly have animal visitors on my property, the photo trap is triggered fairly often; it works satisfactorily across the board and will remain in operation to deliver many interesting shots.