Abstract A solid state bolt-on bicycle accessory having a self-contained power supply indicates vehicle speed and drive sprocket RPM. When the drive sprocket is rotated, magnets located thereon induce a series of pulses in an adjacently located coil. The pulse is received by an amplifier, and differentiated before triggering a monostable multivibrator. The output of the multivibrator drives a suitably damped d''Arsonval meter movement which, when calibrated, provides the bicycle rider with an RPM tachometer reading. Speed is likewise derived from a wheel-mounted magnet assembly which triggers an adjacent coil mounted on the front fork of the bicycle. Another meter movement driven by similar circuitry will indicate vehicle speed.
An electronic tachometer for selective multispeed bicycles having a drive sprocket and at least one wheel, the tachometer comprising: magnetic means attached to said drive sprocket for inducing pulses in a sensor; a sensor coil, said coil located in operative proximity to said magnetic means on the frame of said bicycle to generate a plurality of electrical pulses when said magnetic means rotates with said drive sprocket; means for amplifying said electrical pulses; means connected to said amplifying means for producing substantially square wave pulses; and means for indicating the rotational velocity of said drive sprocket in response to said square pulses regardless of the selected bicycle speed.
Claim 2
Dependent Claim
108 words
An electronic tachometer for selective multispeed bicycles having a drive sprocket and at least one wheel, the tachometer comprising: magnetic means attached to said drive sprocket for inducing pulses in a sensor; a sensor coil, said coil located in operative proximity to said magnetic means on the frame of said bicycle to generate a plurality of electrical pulses when said magnetic means rotates with said drive sprocket; means for amplifying said electrical pulses; means connected to said amplifying means for producing substantially square wave pulses; and means for indicating the rotational velocity of said drive sprocket in response to said square pulses regardless of the selected bicycle speed.
Claim 3
Dependent Claim
188 words
An electronic tachometer for bicycles having a drive sprocket in at least one wheel, the tachometer comprising: magnetic means attached to said drive sprocket for inducing pulses in a sensor; a sensor coil, said sensor coil located in operative proximity to said magnetic means on the frame of said bicycle to generate a plurality of electrical pulses when said magnetic means rotates with said drive sprocket; means for amplifying said electrical pulses; means connected to said amplifying means for producing substantially square wave pulses; means for indicating the rotational velocity of said drive sprocket in response to said square wave pulses; second magnetic means attached to said wheel for inducing pulses in a second sensor; a second sensor coil, said second coil located in operative proximity to said second magnetic means on the frame of saId bicycle to generate a second plurality of electrical pulses when said second magnetic means rotates with said wheel; and switching means for enabling said indicating means to display the speed of said bicycle rather than the rotational velocity of said drive sprocket, said speed being derived from said second plurality of pulses.
Claim 4
Dependent Claim
188 words
An electronic tachometer for bicycles having a drive sprocket in at least one wheel, the tachometer comprising: magnetic means attached to said drive sprocket for inducing pulses in a sensor; a sensor coil, said sensor coil located in operative proximity to said magnetic means on the frame of said bicycle to generate a plurality of electrical pulses when said magnetic means rotates with said drive sprocket; means for amplifying said electrical pulses; means connected to said amplifying means for producing substantially square wave pulses; means for indicating the rotational velocity of said drive sprocket in response to said square wave pulses; second magnetic means attached to said wheel for inducing pulses in a second sensor; a second sensor coil, said second coil located in operative proximity to said second magnetic means on the frame of saId bicycle to generate a second plurality of electrical pulses when said second magnetic means rotates with said wheel; and switching means for enabling said indicating means to display the speed of said bicycle rather than the rotational velocity of said drive sprocket, said speed being derived from said second plurality of pulses.