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picaxe 12 volt car battery

Hello there!


I'm gettting pretty excited with picaxe and want to start building circuits to control gadgets in my car. So, picaxe circuits all seem to run with 4x1.5 volts batteries ( 6 volts). I want to run them in my car: 12 volts. what is the best solution, and the simplest? (i tought about using those car cellphone chargers that convert 1v to 5.5v, but there is gotta be a better way, right?




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LM2940 and a small cap, to reduce ripples



LM2940 is equivalent to 7805, but with a lower dropout,    able to provide 1A 5V.

was developped for automotive use, input has to be bewteen 6V and 26V

hum! good to know there is an easy way to do it. But i'm still in initial stages of electronics. So i guesse I need to have this component build into a little citcuit... where do 12V go, and 5 v come out? How do I connect this to a picaxe circuit 5 volt input?



Read the data sheet - follow the link under the picture - all will be revealed.

on the picture, the +12V input is on the left

the center pin is common ground    (back metal part of the package is also Gnd)

and the right one is the output 


you obviously have to take a LM2940-5   for 5V 

I folowed the link and I think it shows 2 condensers. can I skip the condensers? just connect 1 to +12V 2 to ground and 3 to +5volt?
Skip the capacitors? Not a good idea. they are there for a reason, not just to sell more capacitors a 2c each
Picaxe chips work at 5 volts, not 6v. It might not seem like a big deal but it can be the difference between working and blue smoke.
Well, couldn't you just use the lm2940 connecting to the other 2nd power source for external stuff (v2 in fritsl's picaxe28x1 for dummies)? that way the 6 volts would go to external stuff (such as servos)only. 
Use a DC-DC converter like what Oddbot says. I have a few of these ones which are almost complete switching regulators. So simple to use and cheap, if your input voltage is high enough. Costs about $3 and only requires 2 external capacitors. I can`t find an english datasheet or supplier, but you should know what to look for now.

There is a MAJOR amount of electrical noise in a car which really screws up and possibly fries the PICAXE. You will need to carefully design a power supply circuit to compensate for thois. The best way is to follow Oddbot's suggestion and buy a car adapter, all of this is thne taken care offor you.

For breadboard work or prjects using 4 AA batteries, the LM2950 is great ( add caps on both sides).