Introduction: IOT123 - LIR2032 BATTERY BRICK

About: The tension between novelty and familiarity...

The IOT123 BRICKS are DIY modular units that can be mashed up with other IOT123 BRICKS, to add functionality to a node or wearable. They are based on the inch square, double-sided protoboards with interconnected through holes.

Although the instructions relate to a semi-permanent bond between the BRICKS, the male pin joiner described here can be swapped for a pair (male on consumer/female on provider) of header pins for easy assembly. Also the pin contract (position and meaning of interconnecting pins) relates to the ATTINY85 NRF24L01 BRICKS, but can be modified to suit any other IOT123 BRICK contract.

A switch is sandwiched between the 2 PCBs and the +ve/GND pin are exposed for consumption by other BRICKS. The battery holder is facing down (as it is the less frequented exposed surface) and has a pair of header feet for support/stability.

Step 1: Tools and Materials

    There is a full Bill of Material and Sourcing list.

    1. LIR2032 Battery Holder (1)
    2. LIR2032 Rechargeable Battery (1)
    3. SPDT Side PCB Switch (1)
    4. 1" Double sided protoboard (1)
    5. Female Headers (1P, 1P)
    6. Male Headers (1P, 1P, 1P)
    7. Hookup wire (~8)
    8. Solder and Iron (1)
    9. Strong Cyanoachrylate Adhesive (1)

    Step 2: Circuit Assembly

    1. Insert the power pins (1, 2) and a support pin (3) (male pins with long end pointing into the PCB) into the bottom of the BRICK to be powered.
    2. Place LIR2032 BRICK PCB over the male pins, with bottom facing up. Solder off on bottom.
    3. Depending on what you have the SPDT may need to be trimmed of tabs/pins leaving 3 pins on one side only. On the top, add the SPDT switch (4) and solder off on bottom.
    4. Trim any pin/solder that will come into contact with the LIR2032 holder.
    5. Place LIR2032 holder on bottom of thic PCB; bend +ve pin so that it has a crimp onto big hole on the PCB.
    6. On the top solder Holder Pin on BLACK1.
    7. On the top, trace a wire/bridge from BLACK1 to BLACK2, and solder.
    8. On the top, trace a red wire from RED1 to RED2, and solder.
    9. On the top, trace a red wire from RED3 to RED4, and solder.
    10. On the bottom, add a 1P female headers to SILVER1 and SILVER2, glueing to the side of the battery holder. Solder off on top.
    11. Trim the solder/excess wire from the BRICK to be powered where the SPDT makes contact when joining the BRICKS.
    12. Add some insulation tape to the top of the SPDT.
    13. Join and solder the 2 BRICKS, ensuring the PCBs planes are parallel.

    Step 3: Testing

    As this is a generic power supply for the IOT123 BRICKS, you basically rerun the tests provided for the consuming BRICK. As we have used the 5PIN ATTINY85 NRF24L01 BRICK as an example consumer for this build, just rerun the test provided.

    The suitability of the LIR2032 as a power source depends of several factors: sleep, sensor current usage etc. A 3.3V POWER BRICK which is connected to mains power has been developed.

    Step 4: Next Steps

    As you can see the footprint of the IOT123 BRICKS is favourable against the D1M BLOCKS.

    These two can be used together: Several BRICKS collecting and sending data to a BLOCK, which then publishes to a MQTT server.