Modern Continuity Tester

Modern Continuity Tester is a tool so that you can verify the continuity in the circuits that you do, and it´s imperative that the voltage usage be from 5V to 12VDC for avoiding accidents. This project is based in an LM358, a LED for monitoring its result, and a trimmer of 5K for adjusting it. With the project adjusted, you will obtain the best probes.

What you will need:

Soldering iron

Solder roll

Rotary drill

Drill bits of 1/4" & 5/32"

Wire cutter

Wire stripper

Nose pliers

#22 Wire, 1.5 meters

Step 1: Diagram 1

In the diagram 1, you are going to observe all connections that you have do in the project, and therefore, the entire project is available for you. However, you must follow carefully step by step this diagram so that you can complete the project successfully.

Step 2: Diagram 2

In the diagram 2, you are going to observe all connections that you have do in the project, and therefore, the entire project is available for you. However, you must follow carefully step by step this diagram so that you can complete the project successfully. Once finished the project, you will be capable of adjust it joining its test leads and using a screwdriver for manipulating the trimmer: it will provoke the lit of your Blue LED. Finally, unjoint the test leads of your project and adjust it until it´s turned off its Blue LED while turned on with its test leads joined.

Step 3: Bill of Materials

1 Case ABS Speedy 3.125x2x.875

1 Prototype Builder 1.6" X2.7" PCB Epoxy Glass 0.062" Thick 0.1" Hole Spacing 0.08" Pad Size

1 Led Mounting Hardware T1-3/4 Clear Standard

1 LED,BLUE,WATER CLEAR,T13/4,466nm,3.9V,210mcd, VIEWING ANGLE 9

1 1/2 Watt 3/8" Square Trimming Potentiometer 5k Ohm

1 LM358N

1 IC Socket 8-Pin

1 Diode 1N4148.

3 Resistor Carbon Film 22k Ohm 1/4 Watt 5%

2 Resistor Carbon Film 1k Ohm 1/4 Watt 5%

1 Resistor Carbon Film 10 Ohm 1/4 Watt 5%

1 Resistor Carbon Film 680k Ohm 1/4 Watt 5%

1 Resistor Carbon Film 56k Ohm 1/4 Watt 5%

1 Resistor Carbon Film 8.2k Ohm 1/4 Watt 5%

1 Resistor Carbon Film 1.5k Ohm 1/4 Watt 5%

1 HEAT SHRINK TUBING,FIT-221B-1/16-BLACK,4 FEET,BLACK POLYOLEFIN

1 Binding Post Breadboard Screw Type Chassis Mount 1 Black 1 Red

1 Test Leads Banana 42 Inches 1 Red 1 Black

1 BATTERY HOLDER FOR CR2032,PC MOUNT

2 CR2032 Lithium Battery 3V 225mAh

Step 4: Battery Holder 1

Install the battery holders and solder them on the PCB by noting the polarity of each holder: above holder shows from left to right its polarities positive(+) and negative(-) respectively while bottom holder shows its polarities in opposite form.

Step 5: Battery Holder 2

In the back side of the PCB, connect the polarity negative(-) with the polarity positive(+) of both battery holders by using a wire to join their pins showed in the left side of your PCB.

Step 6: IC Socket & Potentiometer 1

Now, install the IC Socket of 8-Pin and the trimmer of 5K while you note both the polarity positive(+) and the polarity negative(-) of the battery holders in the above side and bottom side of your PCB respectively. That is, the battery holders form an only power supply.

Step 7: IC Socket & Potentiometer 2

In this step, connect the extreme pins of your trimmer while leaving free the middle pin of the same trimmer. For connecting the previous pins, connect left pin to pin 2 and right pin to pin 3 of the LM358.

Step 8: Resistors of 1K Ohm 1

In this step, connect the resistors of 1K to left pin and right pin of your trimmer respectively while leaving free the others leads of the resistors.

Step 9: Battery Holder 3

In this step, you are going to connect LM358 in its pins 4 to GND and 8 to +6V while interconnecting its pins 1 and 6.

Step 10: Resistors to IC Socket, Pin 5

In this step, you are going to connect to LM358 in its pin 5 the resistors of 22K, 56K, and 8.2K while leaving free the other terminal of this last resistor and will only connect the others remaining leads to +6V and GND respectively.

Step 11: Resistors of 680 K Ohm

In this step, you are going to install the resistor of 680K to the middle terminal of your trimmer of 5K while the other lead will be connected to +6V.

Step 12: Installing Resistors to +6V

Connect the resistor of 22K to +6V while the other terminal to the resistor of 1K that have its other lead connected to pin 3 of LM358.

Step 13: Resistors of 1K Ohm 2

From the remaining terminal of the resistor of 1K which was connected its other lead to pin 3 of the LM358, you should draw a red wire.

Step 14: Resistors of 1K Ohm 3

From the remaining terminal of the resistor of 1K which was connected its other lead to pin 2 of the LM358, you should draw a black wire.

Step 15: Installing Resistor to GND

Connect the remaining lead of the resistor of 22K drew of the resistor of 1K and also connected the black wire previously drew in the step 14 to GND.

Step 16: Connecting the Diode

In this step, you are going to connect the diode to pin 7 of your LM358 and to the remaining terminal of the resistor of 8.2K its negative (-) and positive (+) terminal respectively. Also you will connect to resistor of 1.5K between pin 7 of the LM358 and anode of your blue LED..

Step 17: Drawing Connections to Blue LED 1

For drawing connections to Blue LED, draw a white wire from GND and draw other blue wire from the remaining terminal of the resistor of 1.5K.

Step 18: Enclosure 1

In this step, you are going to do a hole of an 1/4" in the enclosure of your project.

Step 19: Enclosure 2

In this step, you are going to do two holes of 5/32" in an extreme of the enclosure of your project.

Step 20: Enclosure 3

In this step, you are going to install the socket for supporting the Blue LED.

Step 21: Enclosure 4

In this step, you are going to install the two Binding Post Breadboard Screw Type Chassis Mount 1 Black 1 Red..

Step 22: Enclosure 5

In this step, you are going to install the Blue LED and also a little bit of heat shrink tubing of 1/16".

Step 23: Installing the Resistor of 10 Ohm 1

Connect the resistor of 10 Ohm between the connectors of your Binding Post Breadboard Screw Type Chassis Mount 1 Black 1 Red.

Step 24: Installing the Resistor of 10 Ohm 2

Now, install the its place the resistor of 10 Ohm.

Step 25: Drawing Connections to Blue LED 2

Connect the blue wire and white wire to the anode and cathode of the Blue LED respectively.

Step 26: Installing the PCB Inside the Enclosure 1

In this step, you are going to install the PCB previouslly assembled inside of the enclosure.

Step 27: Installing the PCB Inside the Enclosure 2

In this step, you are going to install the IC LM358 and the batteries of 3V. Also note that in this same step, you can adjust your project manipulating the trimmer and using a screwdriver on this trimmer will fix the kit before closing the enclosure. Observe the annotations in the diagram 2 so that you can understand how to adjust the project.

Step 28: Closing the Enclosure

In this step, you are going to close the enclosure once adjusted. It´s imperative that the annotations written in the diagram 2 be followed carefully for the best result.

Step 29: Completing the Project

Once closed the enclosure of your project, plug the test leads into the Binding Post Breadboard Screw Type Chassis Mount 1 Black 1 Red so that you can check if everything is OK by probing whether the blue LED is lit when joining these leads.