We used the LM7805 in the TO-220 package.right The radio, the BASIC Stamp micrcontroller, and the payload sensors all require a regulated 5 volt supply.
The LM7805 is simple to use. You simply connect the positive lead of your unregulated DC power supply (anything from 9VDC to 24VDC. Here we are using 9 volt batteries) to the Input pin, connect the negative lead to the Common Ground pin and then when you turn on the power, you get a 5 volt supply from the Output pin.
The 1A current capacity is more than enough for our CanSat 5. Assuming at some given time during the mission, the FRS is transmitting at the peak rating of 300mA and the Basic Stamp is simultaneuosly using up 15 mA, and the sensor is taking 50mA, that's a total of 365mA...so there is more than enough headroom with the LM7805. The problem is whether you have enough batteries to power all of your subsytems. Hence, our decision to go with THREE 9 volt batteries
Spec Sheet
