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PICAXE-08 ALARM PROJECT
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© copyright 2002 - AXE102 Alarm Student Project Notes Version 1.1
Revolution Education Ltd. Email: [email protected] Web: www.rev-ed.co.uk
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Safety!
Never 'short circuit' any battery. Alkaline and rechargeable batteries can provide a very
large current, and can get so hot that they will actually melt the battery box if you short
circuit them! Always make sure you connect the battery around the correct way (red
positive (V+) and black negative (0V or ground)). The microcontroller chip will get hot
and be damaged if the battery is connected the wrong way around.
Using battery snaps.
Battery packs are often connected to electronic printed circuit boards by
battery snaps. Always ensure you get the red and black wires the correct
way around. It is also useful to thread the battery snap through holes on
the board before soldering it in place - this provides a much stronger
joint that is less likely to snap off.
Never accidentally connect a 9V PP3 battery to the battery snap - this will
damage the microcontroller, which only works between 3 and 6V.
Soldering to battery boxes.
Some small battery boxes require wires to be soldered to metal contacts on the battery
box. In this case you must be very careful not to overheat the metal contact. If the
contacts gets very hot they will melt the plastic and fall off. A good way of stopping this
happening is to ask a friend to hold the metal contact with a pair of small pliers. The
pliers will act as a ‘heat-sink’ and help stop the plastic melting.
