Construct Wireless Sensor Case Kit

For instructions on how to configure the sensor and connect it to the PrivateEyePi website please see the following project tutorials.

Basic soldering experience is assumed.  If you are new to soldering, or are a bit rusty, have a watch of some of the excellent How To videos on YouTube.

This build guide shows the various stages involved in building a coin cell board based sensor.  Most of the steps are the same, but additional steps are included which are sensor specific depending on which sensor you are building. 

Start by familiarizing yourself with the components. Lay them out on a table, identify where every component goes before you start to solder.

Step 1.

Construct the center battery pad. Melt a blob of solder where is says "SOLDER PAD HERE" on the center pad as shown in Figure 1. This will give the battery a good connection and ensure a snug fit. 

Figure 1 - Construct center battery pad

Then solder the sides of the battery holder to the pads as shown in Figure 2. Make sure that the pads are heated up nicely and soldered securely as the battery holder will come under pressure when the battery is inserted so you don’t want the battery holder to come loose because of a poorly soldered pad.

Figure 2 - Solder the battery clip to the PCB

Step 2.

Solder the XRF sockets to the PCB as per Figure 3. You want them to line up nicely and by at right angles to the PCB. The easiest way to do this is to connect the sockets to the XRF and place the sockets into place and then turn the PCB over for soldering. The XRF acts to align and ensure correct alignment. 

Figure 3 - Solder the XRF sockets into place

Step 3

Next fit the 100uf capacitor.  Note that the capacitor is polarized, and should have the short leg (with white stripe on casing) going to the hole marked as negative, and the longer leg is positive. Solder the component in place and trim the legs.

Figure 4 - Fit the 100uf capacitor

Step 4

The next steps differ depending on the sensor type. 

Thermistor temperature sensor

Solder the Thermistor in place as shown by the purple dots, and the 10k resistor as shown by the yellow cicles in Figure 5. I would recommend leaving the legs of the thermistor quite long for two reasons: 1) you want the temperature sensor to protrude slightly from the casing to ensure you take a temperature reading from outside the casing and 2) the sensor will get in the way of the battery and you will not be able to insert a battery easily (or at all). Leaving longer legs allows you to bend the sensor out of the way while you insert a battery.

Figure 5 - Placing for the Thermistor (temperature gauge) on the PCB

2 Button Sensor/Reed Switch

Solder the buttons or reed switch (door switch) in place (one or two), shown by the red and orange dots, and the 10k resistor as shown by the black dots in per Figure 6. The resistor shows 1M on the board but anything between 10k and 1M will work. For a reed switch solder one wire to the pad shown by the red dot and the other wire to pad shown by the orange dot. The sensor supports two switches (Button A and B), but you don't need to use both if you don't want to. Tip:Solder the resistor on the back of the PCB, otherwise it will be in the way of the battery holder and you won't be able to insert a battery easily. Also take note of the size of your switches before you start soldering to make sure they don't get in the way of inserting the battery. If you are using reed switches for an alarm then you don't need to worry about this as the wires will not get in the way of inserting the battery.

Figure 6 - 2 Button/Reed Switch sensor placing on the PCB.

Wireless Relay Switch

Connect the relay switch "IN" connector to pin 8 or 9 shown above with the red circles. The RF modules supports being able to switch two relay switches independently.

Wireless sensor case kit breakout board

"IN" connection of the relay

Relay switch

Step 5

Place the sensor in the box as per figure 7.

Figure 7 - Sensor placed in the box

Before soldering in your Thermistor or swicthes plan where you want you want to place the components (inside the box or outside). For the Thermistor it's best to drill a hole in the box lid for the sensor to protrude slightly. Alternately solder the thermistor on the back of the board so that it does not impede the battry clip. For reed switches (door switches) you will want two small holes drilled at the top left of the box in Figure 7 so the wires can easily exit the box. The antennae (white wire in Figure 8) can be curled up and placed quite easily inside the box. However for longer distances you may want to drill a hole in the box and let the antennae protrude.

Placement of the XRF transmitter and external power for testing

For testing sensor you may want to connect an external power source, as I have done in Figure 8. I used an alligator clip to connect the positive and soldered a temporary wire to the underside pad of the battery negative (grey wire). The black wires you see in the picture are connected to an external waterproof thermistor. The external power source I use are two AA 1.5 batteries connected in series to output 3V.

Figure 8 - Placement of the XRF transmitter, and how to use an external power source for testing (Red is +VE, Gray wire is -VE).

For instructions on how to configure the sensor and connect it to the PrivateEyePi website please see the following project tutorials.