The IKEA TRADFRI motion sensor is a versatile and affordable device that integrates seamlessly into your smart home zigbee setup. I personaly use them in a cuple of places, in the postbox to notify me on new mail and in some rooms to switch on the light. However, its reliance on tow CR2023 coin cells can be a bit of a drawback. These small batteries, while compact, tend to have a relatively short lifespan, especially in devices that see frequent use. Further more in my use cases a small form factor is not needed, so I decied I’m tired of frequently replacing the coin cells. My solution is replacing the CR2023 cell with AA batteries.
Why Switch to AA Batteries?
- Increased Capacity: AA batteries have a significantly higher capacity compared to CR2023 coin cells. While CR2023 cells generally provide around 200 mAh, standard alkaline AA batteries offer upwards of 2,000 mAh—a tenfold increase.
- Cost-Effectiveness: AA batteries are more cost-effective over time due to their widespread availability and longer lifespan.
- Sustainability: Reducing the frequency of battery replacements means fewer discarded batteries, making it a more environmentally friendly choice.
- Rechargability: It’s way easyer to find rechargeable batterys in the form factor AA, also there exists rechargable CR2023 Cells, they do have even lower capacity then 200mAh.
Materials Needed
Before you begin, gather the following materials:
- IKEA motion sensor (the one using CR2023 batteries)
- AA battery holder (for 2 AA batteries, we need 3V, so two times 1,5V in series)
- AA batteries (alkaline or rechargeable, depending on your setup)
- Thin wire
- Soldering iron and solder
- optional Electrical tape or heat shrink tubing
- Small screwdriver
Step-by-Step Guide
1. Open the Motion Sensor
- Use a small screwdriver to carefully open the motion sensor and access the battery compartment.
- Remove the CR2023 battery and note the polarity markings inside the compartment. This is crucial to ensure correct wiring later.
2. Prepare the AA Battery Holder
- Take the AA battery holder and check its polarity markings.
- If the holder has wires attached, ensure they are securely connected. If not, solder wires to the terminals for the positive (+) and negative (–) connections.
3. Connect the Battery Holder to the Sensor
- Cut two small pieces of wire to connect the AA holder to the motion sensor’s battery contacts.
You only need to connect the wire to one of the battery contacts, as the contacts of the two CR2023 are wired in parallel in the motion sensor. - Strip the ends of the wires and attach one to the positive terminal of the AA battery holder and the other to the negative terminal.
- Connect these wires to the corresponding positive and negative contacts in the motion sensor’s battery compartment. Use solder for a reliable connection.
4. Insert the AA Batteries
- Place AA batteries into the holder, ensuring they’re correctly oriented.
- Double-check all connections and ensure they’re secure.
5. Test the Motion Sensor
- Test the functionality of the motion sensor.
- If it doesn’t work, recheck the polarity of your connections and the charge of the AA batteries.
Important Considerations
- Voltage Matching: A single CR2023 battery provides 3 volts, so if you’re using AA batteries, ensure the combined voltage matches the original specification. Two 1.5V AA batteries in series provide 3 volts, while rechargable AA batteries might only have 1.2V AA, so two of them might not suffice without additional modifications.
- Device Integrity: Modifying the device may void its warranty. Proceed only if you’re comfortable with the potential risks.
- Aesthetics: The AA battery holder will be external, which may impact the device’s appearance. Take care to position it neatly for a cleaner look.
- Version: My motion sensor is the version E1525/E1745, there might be different or newer versions with different wireing schemes
Conclusion
With this simple modification, your IKEA motion sensor can enjoy a much longer operational lifespan without frequent battery replacements. By using AA batteries, you’ll save money, reduce waste, and eliminate the inconvenience of constantly changing CR2023 cells.
This project is an excellent introduction to DIY electronics, and with a little patience, you’ll have a more efficient and sustainable motion sensor in no time. Happy tinkering!
