A clock driver and corresponding method are provided. The arm positioning member helps to maintain the back of the user in a substantially upright position as the arm positioning member applies and releases reciprocatively and alternatingly in a substantially vertical path of travel of the upper body of the user against the force on the resistance member during repetitions of use of the device. A first of the Schmitt trigger circuits detects the voltage appearing on the output of a reference voltage generator falling below a minimum threshold voltage level. The sensor device coalesces the one or more received alarm messages from the one or more upstream sensor devices with the alarm message generated at the sensor device, to form a coalesced alarm message, and transmits the coalesced alarm message downstream towards the downstream destination device, after expiration of the delay.