In this instructable you will be able to make a continuity tester for less than 50 cents
Step 1: INTRODUCTION
In electronics a continuity tester is a very crucial tool. It helps you to troubleshoot your circuit and find faults in it.
The basic idea is that the device consists of two probes which when come on contact make a buzzing sound.
While troubleshooting a circuit the probes are touched to the two contacts which needs to be tested, if they are connected the continuity sensor makes a buzzing sound.
Most multimeters are equipped with a continuity tester but some are too slow or you can make one if you don't have a multimeter on don't like to carry one always
Step 2: THE MATERIALS REQUIRED
The materials you would be requiring for this build are very cheap and would cost you about 50cents to 1$ depending on the place you live and the place you buy them from.
The materials you would require are:
1. AAA Battery
2. Buzzer (preferably small)
3. One male-to-male jumper ( or you can use headers or pins)
4. An old thick sketch pen ( of course you can buy a new one if you don't have one)
5. Any pen
6. Some wire
The tools you would require
1. Soldering iron
2. Hot glue or any other adhesive
3. Wire strippers or scissors
5. Sandpaper(100 grit)
Step 3: THE CIRCUITRY
The circuit is the simplest that can be. It is very similar to the basic light bulb circuit that everyone tried in their childhood.
The only difficult part is that you will have to sand the battery contacts before you can solder wires to them.
Also check the polarity of the buzzer. The longer leg is the positive end and the shorter one is the negative end.
Step 4: MAKING THE BODY
For making the body the first thing you need to do is to clean out the pen. Open the pen and pull out the refill and the tip with pliers. Then you can stuff everything in the pen.
The pins or one end of the male to male jumper will become one of the probe and the second end or the second pin will become the second probe.
Step 5: CLOSING THE BODY
After you have fit in everything and one probe is poking out of the pen and you have tested the circuitry by touching the 2 probes, using hot glue secure every thing including the pin or the male to male connector.
The next thing is to poke a hole through the cap you had taken out and thread the other probe through it.
Secure the cap back on and test your circuit.
Step 6: MAKING THE SECOND PROBE
For the second probe take an old pen and remove the back cover and pull the refill, poke a hole and pass the wire hanging out of your first probe through the hole.
Solder the other end of the male to male connector and then secure it with hot glue at the tip of the pen.
Step 7: TESTING BEEP BEEP
Touch the two probes and you should hear a beeping sound.
If you don't hear the beeping sound then the circuitry is not working the most common problem being that the connection from the battery is broken.