Solar iPod Charger Schematic
The Solar Panel
To accomplish our iPod solar charger we acclimated a 250mA 6 Volt Solar Console (available in the REUK Shop). Alike in the brightest sunshine the voltage is not badly aloft that of the iPod battery, and the accepted is affluence abundant to allegation the array in a few hours in ablaze altitude (even in the UK!).
A blocking diode should be acclimated (in the absolute solar console lead) to anticipate the iPod array from boring clarification at night if it is still affiliated to the panel. Unforunately this after-effects in up to 0.7 Volts actuality absent as calefaction in the diode, so it can be larboard out if you adopt to accept a faster charger which will allegation the array in lower ablaze conditions.
Note that abounding solar panels are supplied with a branch adapted blocking diode.
In adjustment to adapt the voltage from our 6 Volt solar console we acclimated an LM317T dent (available from the REUK Shop) in the afterward cool simple circuit:A blocking diode should be acclimated (in the absolute solar console lead) to anticipate the iPod array from boring clarification at night if it is still affiliated to the panel. Unforunately this after-effects in up to 0.7 Volts actuality absent as calefaction in the diode, so it can be larboard out if you adopt to accept a faster charger which will allegation the array in lower ablaze conditions.
Note that abounding solar panels are supplied with a branch adapted blocking diode.
Voltage Regulator
...where R1 is a 270 Ohm resistor, and R2 is theresistor used to set the output voltage according to the following equation:
R2 = R1 * ( (VOUT/1.25) -1 )
Since our desired charging voltage is 5 Volts, we see that ideally R2 would be 270 * ((5/1.25) -1) = 810 Ohms. This is not a standard resistor size, however we had an 820 Ohm resistor which should result in an output voltage of 5.05 Volts.
Wiring up the aloft ambit on a prototyping breadboard with a 270 Ohm R1 resistor, and 820 Ohm R2 resistor we can affirm that the achievement voltage is 5.06 Volts - absolute for our iPod charger. It is capital to analysis that the achievement voltage is about 5 Volts application a acceptable multimeter afore attempting to allegation your iPod or the array and/or iPod itself could be damaged.
iPod Solar Charger Prototyping
Connecting the Charger to the iPod
The iPod is supplied with a USB cable. One end is acquainted into the iPod and the added end has a macho USB-A plug.
It can generally be cheaper to buy a cable with a adapted changeable USB-A adapter and cut it off to use in this project. Simply affix the red USB cable wire to the 5V absolute achievement from the LM317T, and the atramentous USB cable wire to the arena (negative).
According the blueprint beneath the 5 Volt achievement from the LM317T should be affiliated to pin 1, and the arena (negative) affiliated to pin 4.
