An electronic transaction card communicates with an add-on slot of an intelligent electronic device. The add-on slot may be a memory card slot. The intelligent electronic device may be a mobile phone or other device with or without network connectivity. The electronic transaction card may have magnetic field producing circuitry compatible with magnetic card readers, smartcard circuitry, other point-of-sale interfaces, or any combination thereof.

A power pack for a power tool. The power pack includes an electric motor configured for driving engagement with the power tool. The power pack also includes a motor controller having a relay circuit connected a electric motor. The relay circuit includes has a switch selectively connected to a power supply. The power supply powers the electric motor. The motor controller also includes non-transitory computer-readable storage media having computer-executable instructions for monitoring operation of the stored power pack. When executed by at least one processor, the computer-executable instructions cause the at least one processor to: monitor input data relating to operation of the power pack; determine, based on the input data, that operation of the power pack deviated from an ideal state; and, based on the determination of deviation, cause the switch to electrically disconnect the electric motor from the power supply.

The embodiments described herein regard removable accessories for a wireless device. A removable accessory for a wireless device can include hardware and a power charging capability to allow the wireless device to use functions of the removable accessory and to wirelessly charge the removable accessory. The removable accessory can be charged wirelessly directly from the wireless device or from an external wireless charging pad. The removable accessory can be configured to coordinate shared wireless charging from an external wireless charging pad to allow charging for both the wireless device and the removable accessory.

A power pack for a power tool. The power pack includes an electric motor configured for driving engagement with the power tool. The power pack also includes a motor controller having a relay circuit connected to a electric motor. The relay circuit includes a switch selectively connected to a power supply. The power supply powers the electric motor. The motor controller also includes non-transitory computer-readable storage media having computer-executable instructions for monitoring operation of the stored power pack. When executed by at least one processor, the computer-executable instructions cause the at least one processor to: monitor input data relating to operation of the power pack; determine, based on the input data, that operation of the power pack deviated from an ideal state; and, based on the determination of deviation, cause the switch to electrically disconnect the electric motor from the power supply.

An electronic transaction card communicates with an add-on slot of an intelligent electronic device. The add-on slot may be a memory card slot. The intelligent electronic device may be a mobile phone or other device with or without network connectivity. The electronic transaction card may have magnetic field producing circuitry compatible with magnetic card readers, smartcard circuitry, other point-of-sale interfaces, or any combination thereof.