Practical Arduino Cool Projects for Open Source Hardware- P25: A schematic or circuit diagram is a diagram that describes the interconnections in an electrical or electronic device. In the projects presented in Practical Arduino, we’ve taken the approach of providing both a photograph and/or line drawing of the completed device along with a schematic. While learning to read schematics takes a modest investment of your time, it will prove useful time and time again as you develop your projects. With that in mind, we present a quick how-to in this section.: A schematic or circuit diagram is a diagram that. | CHAPTER 12 WATER TANK DEPTH SENSOR EXTERNAL MOUNT Assemble the Sensor Housing If you intend to mount the sensor submerged inside the tank you will need to use your own creativity to determine a method to house and seal it. A good starting point would be to assemble the sensor box following our instructions and then add large quantities of silicone sealant and a long tube attached to transducer port 2 to exit the top of the tank. For our prototype we mounted the pressure transducer inside a small PVC project box by drilling holes in the back of the box and attaching the transducer using small bolts and plastic spacers to hold it 10mm clear of the back see Figure 12-9 . The box already had small spacers molded in place but because they were in the wrong location and not quite long enough we didn t use them and added our own instead. Spacers are necessary to provide enough clearance for the sensor hose to be attached to the port on the transducer and without them the transducer port won t have enough clearance from the back of the box. After test-fitting the transducer in the box measure the distance from the front edge of the box to the center of the port on the inside of the box and then use a felt-tip pen to transfer the measurement onto the outside. 219 CHAPTER 12 WATER TANK DEPTH SENSOR Figure 12-9. Transducer mounted inside weatherproof box using plastic spacers and M3 bolts You can see in Figure 12-9 that the transducer is mounted upside down with the part number marking hidden on the other side of the case. This is to allow port 1 the port opposite pin 4 which is on the top right in the picture to be aligned vertically near the center of the box and provide enough clearance for the cable gland. Your physical mounting arrangement may vary of course so you ll need to plan how you will mount the transducer while retaining sufficient clearance for connections to it. Measure sideways from one edge of the box and once again transfer that measurement to the outside .
