TOUCH AND GO SWITCH | JAMECO PART NO. 2173722

Part No. Qty. Description

35975 1 Diode,1N4001,1A (D2) 38236 2 Transistor,2N2222A,TO-18,NPN (Q1, Q2) 93761 1 Capacitor,Radial,100uF,25V (C2)177990 1 Diode,Schottky,1N5822,3 A (D1)334473 1 Green LED,505 nm (D3)240813 1 Potentiometer, 50 K ohms (R6)216452 1 Battery Snap,6 ",26 AWG (J1)93835 1 Capacitor,Radial,1000uF,25 V (C1)691817 1 Resistor,CF,10M ohm,1/4 Watt (R2)853610 1 POT,Sealed,Cerm,1MEG,1/2 Watt (R3)1742997 1 Low Dropout Regulator,IC,LT1963 (U1) 2157167 1 Resistor,CF,10K ohm,1/4 Watt (R1) 2157175 1 Resistor,CF,100 ohm,1/4 Watt (R4) 2160956 3 Resistor,CF,3.3 Kohm,1/4 Watt (R5,R7,R8) 198731 1 9V Battery --- 1 PCB--- 1 Instructions

PCB TOP SIDE PCB BOTTOM SIDE

Step 1-- Place the PCB with the top side up. Apply a small amount of thermal grease in the

rectangular pad area for U1.

Step 2-- Locate item U1 from the bill of materials and place it in the location shown

below with the component leads aligned with the PCB pads:

Step 3-- Solder the five component leads to the pads making sure to prevent solder shorts

between pads.

Step 4--In the area near the U1 tab, solder a small area of the tab to the board as shown

below. It may take a little longer to heat and flow the solder here. The small solder at the end of the tab and the heat-sink grease under the part will provide a good connection that allows any heat in U1 to be quickly dissipated into the board. NOTE: An alternate part case type (T0-220) could also be used at the U1 location, as the PCB was designed to use either type part. With the T0-220 type part, the tab does not need to be soldered, but a 4-40 bolt and nut are used to press the part and thermal grease in contact with the PCB.

Step 5--Use paper towel to wipe away any excess thermal grease that may have oozed

out from under U1.

Step 6--Now install Q1 and Q2, which are both 2N2222A transistors, in the locations

shown below. Install the part so the tab matches the white tab printed on the PCB.

Step 7--On the back-side of the board slightly bend the transistor leads apart to help hold

them in place to the board and solder the three pads for both Q1 and Q2.

Step 8--Use the diagonal cutters to clip the leads short. This pattern of inserting the part,

bending the leads, soldering and clipping the leads will be repeated for the remainder of the parts to be installed.

Step 9--Install and solder the two diodes D1, D2 as shown below, make sure to properly

locate the banded end of the diode as shown on the PCB.

Step 10-- Install and solder all six of the resistors as shown below:

Step 11--Install and solder the LED D3 as shown below. Note the flat end of the LED

corresponds to the flat edge shown on the PCB.

Step 12--Install and solder C1 and C2 as shown below. Note the case of each capacitor

has negative markings on one side of the part. The opposite lead is the positive and must be installed into the solder pad that has a square shape. Correct polarity of these parts is critical.

Step 13--Install and solder the two trim-pots R3, R6. Notice the PCB topside image shows

which side the trim-pot screw should be placed on.

Step 14--Connect the 9 volt battery clip by soldering the wires in place as shown below

observing the proper polarity. This completes the assembly of the circuit. Use isopropyl alcohol and a cleaning brush to remove any excess soldering flux or residue. Allow the board to air dry for 10 to 15 minutes.

CIRCUIT TESTING AND ADJUSTMENT A 9 volt battery can provide a simple way to adjust and confirm the circuit is correctly assembled. NOTE: Your specific application may use a power supply or a different battery source, however, using the 9 volt battery is a good idea at this step so you can test out the circuit for correct wiring and get familiar with the adjustments. After the circuit has been confirmed good, the battery clip wires can be removed and any external D.C. source from 3 volts to 20 volts can be connected. The circuit can be used in a variety of applications that require touch activation. For now, you will need to add two soldered jumper wires at the JP1 and JP2 locations to allow testing of the circuit using the built in PCB touch pad. Test Steps 1) Use a small regular blade screw driver to turn the trim-pot labeled TIME DELAY, 25 rotations counter-clock wise (this sets the circuit to a minimum time delay). 2) Connect a fresh 9 volt battery to the battery clip. 3) Use a finger to touch the circular grid area on the end of the printed circuit board. The on-board green LED may light briefly. If the LED does not light, try using the screwdriver to turn the trim-pot labeled VOLTAGE clock wise a few turns to increase output voltage. 4) Now touch the switch pad again and see if the on-board green LED lights up. If the LED does not light up, keep turning the VOLTAGE trimpot C.W. (increased output voltage). If the LED eventually lights, go on to step 5. If the LED does not light, there is a wiring problem. Remove the battery from the clip and recheck the kit to see if there is a poor solder connection or an assembly error. After correction of the circuit, start at Test Step #1. 5) At this point the time delay is set to minimum, which makes it difficult to measure the output voltage. Turn the TIME DELAY trim-pot 3-4 turns C.W. which should increase the amount of the time delay to a few seconds. 7) Use a digital voltmeter set to measure D.C. voltage. Connect the meter leads to the pads marked REGULATED POWER OUT and GND. Soldering wires to the pads and then connecting the wires to the digital voltmeter leads may make it easier to measure the voltage. 8) Press the touch pad grid to activate the circuit, use the meter to measure the output voltage. Adjust the VOLTAGE trim-pot to set the voltage to 5 volts D.C. 9) At this point the output voltage regulation is working correctly. 10) Now you can make adjustments to the TIME DELAY trim-pot, C.W. for longer times, C.C.W. for shorter times. This will determine how long your circuit keeps the 5 volts present at the output.

ADDITIONAL CIRCUIT INFORMATION You will note the touch activation pad portion of the circuit board can be kept connected to the main PCB and either the front or the back side of the pad can be accessible in you project for activating the circuit. Additionally you can leave the JP1 and JP2 jumpers off, placing the PCB on a flat surface you can snap off the touch pad potion or use a saw to cut off the pad at the routered slots. This will allow you to wire the touch pad at a more remote location (the circuit has been tested with the touch pad up to 50 feet away from the main circuit). Regulated output supply information

• The regulated output voltage from the circuit is not capable of exceeding the input supply voltage.

• For the circuit to provide a stable regulated output, the input voltage must be 2 to 3 volts greater than the output regulated voltage desired. Some suggested input power supply settings and common output voltages are provided below:

For a 5 volt regulated output, provide a 7 to 10 volt input supply For a 9 volt regulated output, provide a 11 to 15 volt input supply For a 12 volt regulated output, provide a 14 to 20 volt input supply

• Having a large difference between the input voltage and the regulated output voltage requires the U1 regulator to dissipate greater amounts of heat and limits the amount current it will supply. For example, if a regulated 3 volt D.C. output is required, it would be better to provide a 5 or 6 volt D.C. input instead of a larger voltage like 20 volt D.C.

• TIME DELAY trim-pot will determine the length of time that the regulated voltage appears at the circuit output. Time delay settings can be set from a minimum of 2 seconds to a maximum greater than 30 minutes.

TOUCH PAD OPTIONS There are a variety of options for setting up the touch pad(s) to trigger the circuit.

• Using the circuit board provided, the printed circuit board can be positioned inside your project case so that the touch pad grid on the circuit board is exposed to the user.

• The touch grid pad on the end of printed circuit board can also be clipped off and wires can be used to extend the distance between the circuit board and the touch pad grid. This allows mounting the touch grid pad anywhere that is convenient for use.

• You can also make your own touch pads in larger sizes (for activation by touching a palm instead of a finger) by using the suggested materials and steps below:

Aluminum foil tape is available at most hardware stores, similar to what is shown below, and is useful in making your own larger touch pads

The aluminum foil tape can be placed on any non-conductive surface. Cut two pieces and place them side by side with an 1/8th inch gap. Take two wires and strip off ½ inch of the insulation. Use heavy tape to hold the stripped ends of the wires in contact with the top surface of the aluminum tape or use conductive epoxy to bond the wires to the aluminum tape. Solder the other end of the wires to the circuit at pads JP1 and JP2. The figure below illustrates this type of touch pad. Aluminum foil tape works well because finger or hand oils will not cause the tape surface to corrode or oxidize the same way copper tape would. You can use multiple pads in parallel to trigger the circuit from multiple locations. The circuit has been tested with wires as long as 50 feet. It is best not to run the wires over motors or higher power circuitry that could create false triggering of the circuit. For wires run over longer distances

Solder the wires to the circuit board JP1 & JP2

Tape down the wires

Aluminum Foil Tape

the best wire to use is audio wire cable that has two insulated inner conductor wires tied to JP1 and JP2 and one bare ground shield wire. Solder the shield ground wire to the circuit board ground. Leave the ground wire un-connected on the end of the cable where the touch switch is located. With a little modification you can use the aluminum tape above on a metal conductive surface as well.

Solder the wires to the circuit board JP1 & JP2

Tape or use conductive epoxy to hold down the wires

Aluminum Foil Tape

Insulating Tape

Conductive metal surface

APPLICATION IDEAS

9 volt Battery

Touch activated light

9 volt Battery Touch activated fan

5 volt fan

SW1

POWER IN GND

REGULATED POWER OUT GND

POWER IN GND

SW1

SW2

POWER IN GND

REGULATED POWER OUT GND

High intensity white LEDs with current limit resistors

There are many other applications that you can discover. Have fun!

Display Lights

Higher voltage

Touch activated light display

Touch switch controls larger voltages

SW1

SW2

POWER IN GND

REGULATED POWER OUT GND

PROJECT POWER SUPPLY

SW1

SW2

POWER IN GND

REGULATED POWER OUT GND

PROJECT POWER SUPPLY

RELAY

Micro-controller circuitry with display lighting effects

software