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This circuit has been developed to add a USB charging port to a bicycle for charging a mobile phone. The input supply for the circuit is produced by a dynamo (6V, 3W dynamo) in the bicycle. The circuit uses few components, which help in keeping the size, weight and cost of the unit down. Circuit and working The circuit is based on LM2596-5.0 (IC1). Its configuration, with minor changes, generally reflects the recommendations included in Texas Instruments’ datasheet of LM2596-5.0. The IC provides all active functions for a step-down (buck) switching regulator, capable of driving a 3A load with excellent line and load regulation. The output of the regulator is 5V. It operates at a switching frequency of 150kHz, thus allowing smaller-sized filter components than what would be needed with traditional lower-frequency switching regulators. Fig. 1 shows the circuit diagram of the bicycle USB charger. Fig. 1: Circuit diagram of the bicycle USB charger    The alternating voltage genera...

T his  automatic  bicycle  light  makes cycling in the dark much  easier (although you still need  to pedal of course). The circuit  takes  the  ambient  light  level  into account and only turns on  the light when it becomes dark.  The light is turned off when no  cycling has taken place for over  a minute or if it becomes light  again. The biggest advantage of  this circuit is that it has no manual controls. This way you can  never ‘forget’ to turn the light  on or off. This makes it ideal for  children and those of a forgetful  disposition. Bicycle Light Image : To detect when the bicycle is  used (in other words, when the  wheels turn), the circuit uses a  reed switch (S1), mounted on  the frame close to the wheel.  A small magnet is fixed to the  spokes (similar to that used with  most  bicycle  speedometers),  which  ...

The LED bicycle light that we described in the July/August 2009 edition of Elektor has proved very  popular. The author was particularly struck by the basic design, but as always, there is room for a little improvement! Below we describe two enhanced variations on the original theme. Both circuits are, like the 2009 original, powered from a 6 V (rechargeable) battery, shown here as Vl. The simpler of the two circuits, which consists of four transistors, is in function essentially the same as the original version. lt takes the form of a boost converter with feedback provided by the voltage drop across a current sensing resistor, in this case R2. A value of 6.2 O for R2 is suitable for use with four white LEDs at D4 to D7, and gives an LED current of approximately 20 mA. The 250 mW Zener diode D10 is provided to limit the output voltage in the case that the LED chain should go open-circuit, pulling  the gate of the  MOSFET to ground via T3, T1 and T2 if the output voltage exceeds the br...

Just like cars that measures the distance it can travel, you can also do it with your bicycles. We usually keep track of our mileage to see how far our strength can go but would it be of great use if we track it because we are maintaining a workout everyday considering the calories we are burning. If you want to make your own odometer, you will need a micro controller that generates pulse and a MOSFET that converts those voltage pulses. Just remember to check your batteries all the time. The best way of burning calories is to move those muscles everyday! Set your bikes and your odometer! Burn fats! Streamcircuits

Just like cars that measures the distance it can travel, you can also do it with your bicycles. We usually keep track of our mileage to see how far our strength can go but would it be of great use if we track it because we are maintaining a workout everyday considering the calories we are burning. If you want to make your own odometer , you will need a micro controller that generates pulse and a MOSFET that converts those voltage pulses. Just remember to check your batteries all the time. The best way of burning calories is to move those muscles everyday! Set your bikes and your odometer! Burn fats!

Flashing 13 LED unit, 3V supply, Also suitable for jogger/walkers This circuit has been designed to provide a clearly visible light, formed by 13 high efficiency flashing LEDs arranged in a pseudo-rotating order. Due to low voltage, low drain battery operation and small size, the device is suitable for mounting on bicycles as a back light, or to put on by jogger/walkers. IC1 is a CMos version of the 555 IC wired as an astable multivibrator generating a 50% duty-cycle square wave at about 4Hz frequency. At 3V supply, 555 output (pin 3) sinking current operation is far better than sourcing, then LEDs D1-D6 are connected to the positive supply rail. In order to obtain an alternate flashing operation, a second 555 IC is provided, acting as a trigger plus inverter and driving LEDs D7-D12. D13 is permanently on. The LEDs are arranged in a two series display as shown below, with a center LED permanently on. This arrangement and the alternate flashing of the two series of LEDs provide a pseudo...