I've been working on this seasonal project for a few weeks but have been awaiting a shipment of LEDs from a Chinese supplier which finally arrived yesterday enabling me to complete the project.
It is a pair of LED headlamps built into dynamo lamp housings which come as standard on Ezee bikes. The reason for the pair is to give both my bikes convenient and bright lights using a large number of LEDs and running from the main battery. The lamp for the Sprint contains 55 LEDs and the faster Torq has 63 LEDs, arranged in 6 & 7 series chains of 8 and 1 chain of 7, the chain of 7 serving a secondary purpose as a voltage regulator for the 555 timer to provide the flashing function. Constant brightness is ensured by an LM317 regulator dropping the battery voltage to 28V, the current in each LED chain being then limited to 25mA by a series resistor.
The original reflector was removed from the dynamo lamps and replaced with an aluminium plate with holes drilled for the LEDs, the plate also serving as a heat sink for the voltage regulator seen fitted below. The metalwork was marked out by a method I often use when high accuracy is not required, that is to simply stick a computer generated template to the metal and use that as a cutting and punching guide.
The flasher module seen below is a simple 555 circuit built on stripboard and designed to give a flash rate of 2.5Hz and a duty cycle of 20% which ensures high visibility and very low power consumption. After testing the modules were coated in epoxy resin and encased in shrink tube to give mechanical strength for the high vibration environment at the front of a bike.
The lamp is controlled by a miniature toggle switch with weatherproof cover mounted in a very convenient bulge on the back of the lamp housing and arranged to give Flashing - Off - Steady. The red "blob" is the flasher module and the black "blobs" are the series resistors, all encased in shrink tube.
The Sprint lamp was finished yesterday and tested last night around a local unlit country park where it proved very satisfactory, the Torq lamp was finished today but heavy rain is preventing a proper test.
It is a pair of LED headlamps built into dynamo lamp housings which come as standard on Ezee bikes. The reason for the pair is to give both my bikes convenient and bright lights using a large number of LEDs and running from the main battery. The lamp for the Sprint contains 55 LEDs and the faster Torq has 63 LEDs, arranged in 6 & 7 series chains of 8 and 1 chain of 7, the chain of 7 serving a secondary purpose as a voltage regulator for the 555 timer to provide the flashing function. Constant brightness is ensured by an LM317 regulator dropping the battery voltage to 28V, the current in each LED chain being then limited to 25mA by a series resistor.
The original reflector was removed from the dynamo lamps and replaced with an aluminium plate with holes drilled for the LEDs, the plate also serving as a heat sink for the voltage regulator seen fitted below. The metalwork was marked out by a method I often use when high accuracy is not required, that is to simply stick a computer generated template to the metal and use that as a cutting and punching guide.
The flasher module seen below is a simple 555 circuit built on stripboard and designed to give a flash rate of 2.5Hz and a duty cycle of 20% which ensures high visibility and very low power consumption. After testing the modules were coated in epoxy resin and encased in shrink tube to give mechanical strength for the high vibration environment at the front of a bike.
The lamp is controlled by a miniature toggle switch with weatherproof cover mounted in a very convenient bulge on the back of the lamp housing and arranged to give Flashing - Off - Steady. The red "blob" is the flasher module and the black "blobs" are the series resistors, all encased in shrink tube.
The Sprint lamp was finished yesterday and tested last night around a local unlit country park where it proved very satisfactory, the Torq lamp was finished today but heavy rain is preventing a proper test.
