Body Detecor Casing

The concept that we used to decorate our project casing is by using  design of music box which is we put some ribbon around it and small ribbon at the top. The design that we use is simple to compare to other project since our project also not really big. If we stick with the actual circuit that consist of two board, it may be will contribute to the big size of casing compare to the one that we used now. 

The casing is built by hard plastic. It can stand a bit harder comparing to the other plastic. It easy to be decorate since the shape in solid shape. In fact, due to the casing size, there is not much that we can do because it too small. The ribbon that we put around the body is just to make it a little bit good looking and nice. The little the cute one. 

This is how it look like after we done decorating it. As simple as it :)

Drill the Casing

Drilling is also one of the part of the project. We do the drilling for our project casing, which is we need to make the hole for two l.e.d, metal sensor (coil) and also the cable for the battery and switch. Drilling also needed when we want to drill the PCB board hole for the components. Drill have several type of the drill bullets, it have a big one and also the smallest one. So that, we can adjust the bullet according to which bullet we want. It is easy handling and easy to change the bullet, otherwise it come up with the small size of drill and together with the socket and charger in one small red box. 

Before start drilling, we need to measure and marking the hole that we want to drill. This is because it can help us to ensure which part that we want to drill. If we did not marked it, then it could be a possible that the hole we do might be not as we expected. The mark of the casing can be only use pencil or marking pen. We just need to measure the size that we want then mark it before start drilling. Make sure the way of handling the drill is correct. Hold the drill tightly as the safety for us and people around us during drilling.

Here the figure on how we do drilling and the figure how do the casing look like after the drilling process in done. The another one hole that left is actually for the null button of potentiometer but then we change the position to the left, so that the hole is not needed anymore. We decide to leave it like that to decorate and put something at the top. 

Solder the PCB Board

Solder is the next step after done constructing the circuit. In this step, it is necessary to do it carefully because here we will dealing with the dangerous tools such solder that have been heating up for a few time. So that, make sure that we will do the soldering very properly. Beside, the reason why we need to do the soldering properly is because we want to make sure the connection of the circuit would not have any error after soldering the PCB board. 

Some people say soldering is very easy and simple but for me, it is not easier as what we though. This is because other than ensure that every components in right position, we need to ensure that we will soldering the components nicely. It means we need to carefully using the solder ion while soldering. It is nice if we can ensure all the solder ion that we solder on the components is in same shape. We cannot put too much solder ion and we also cannot put too little solder ion. The solder ion will be melting on the components once it touch with the heat up solder. Figure below show the solder and solder ion look like. 

If during soldering we make an error connection or we accidentally put too much solder ion on the components until it get touch with the other component, then we can suck the solder ion by using sucker. The step to do it just by put the solder ion to the ion that already been soldering, then press the sucker to suck the melting solder ion. Ensure that the solder ion that we suck is properly suck to avoid it by double soldering. If it been double soldering, then it will look not so nice at back of the PCB board. Down here is the figure of the sucker.

Construct Body Detector Circuit

After done etching the PCB board, the next step is to construct the circuit on the PCB board. It is very important to check properly the circuit diagram to prevent no error connection after done the construction. To ensure that the connection is correct, we must check and keep refer to the schematic diagram and PCB layout. Besides that, we also must check the components properly by using Multimeter. For an example if we want to construct resistors, it is important to ensure the value is correct to the schematic and PCB layout. 

Also, we need to make sure that there is no touching between the components with each another. This is because if there is touching between the components, then it will make the circuit may be did not functioning very well as what we expected. Since the circuit that we dealing with was high sensitivity frequency circuit, so that it could be high possible for the circuit get many error if the connection did not constructing properly. 

During doing the construction, we also need to consider about the looping or jumper connection. For sure that most of the circuit that we dealing with have a looping or jumper connection, so that we need to cut the jumper properly to ensure the connection. Even though maybe there is many hole on the PCB and it make the construction a bit hard, but we must do the construction very carefully. Using long nose to hold the components that hard to be put on the PCB board such IC's. For the components such transistors, diode, L.E.D, capacitors, variable resistors, relay and buzzer, we must check the negative positive first before simply put it on the PCB board. For the transistors, the connection of emitter, base and collector should be in correct position. 

Here the figure of the circuit after done the construction 

PCB of Body Detector

In process to construct the full circuit, the first thing that need to do is construct the schematic diagram and PCB layout. To construct the schematic diagram, we need to use Multisim software. It used to see and ensure the connection is right. After done the schematic diagram, then we may convert the circuit into PCB by using the Diptrace software. The reason why we need to construct first the circuit by using multisim and diptrace software is because it can easier our work to see the circuit connection and troubleshoot it when it have an error connection. Here the figure of our PCB for Body Detector circuit. 

            

The PCB layout from the bottom side view 

   

  

The PCB layout from the top side view 

Both of this figure showed the circuit connection from top and bottom side view. By looking at the bottom layout, we may see the cooper connection and the components hole to solder. And by looking at the top layout, we may see the components symbols and position. So that, it may easy for us to solder the PCB. After done the PCB, then we may start etching the PCB board. The etching step is same as the previous step that i wrote at my previous post. We may use the same step to do the PCB.

The PCB board after done etching 

Equivalent components (Relay)

RLA is stand for relay. This body detector consist of component such relay with value 5v p.c.b mounting miniature relay 200mW operating power (2-pole changeover). A variety of miniature relays would be suitable as long it provide that the nominal operating power does not exceed 500mW. The output of monostable IC2b at pin 9 provides current for switching transistor TR2, which in turn controls relay RLA. The actual relay that suppose be use in this circuit is the large one that it is almost same like potentiometer. But since the size was too large for the circuit, then we decide to change it with the another type of relay. We replace it with the same power and value, it just the shape that different which is the second one that we replace is rectangular shape blue colour. This relay will be trigger with "crackle" or "click" sound when it functional in the circuit. Since that, it show that the relay is functional work. 

Equivalent component (Variable Resistor)

There is four variable resistor that is needed in this Body Detector circuit, which is one variable resistor with value 200ohm-500ohm multi turn wire wound potentiometer, one variable resistor 470k type of vertical sub-miniature carbon preset, linear cermet preset 100ppm degree temperature coefficient and the last variable resistor is two type of multi turn horizontal cermet preset with value of 50k. Among this four potentiometer, there is two of it we change with the another equivalent components which is VR2 and VR3 50k. We change this components because it is not enough spacing to put it in the PCB board. Since we combining the two part of the board circuit to become one board, it make the size of the PCB board smaller than the actual size. So that, we find another variable resistor 50k that equivalent and same function with the actual components to replace it. The biggest different between this two type of variable resistor is by the colour and size. The actual variable resistor is in red colour and it is big size. However for the replacing component of variable resistor is more smaller and it is yellow colour. This variable resistor can be turn into the maximum turning of 50k. Here the figure of the component. 

Equivelent component (DIP switch)

In the Body Detector circuit, there are some of the components that we had changed. It is such DIP switch that suppose is 3-pole 4-way rotary switch. The reason why we change this component is because we want to make the circuit more easy to dealing with. Beside it also easier us to construct on the PCB board. The actual switch is actually the rotary switch which is it can be rotate or turn over it due to the function mode of "sleep", "activate" and "adjust". However, since the switch size was too big to be put in the circuit, so that me and my partner decide to change it with the another switch that equivalent to. The DIP switch that we changed also have the 4-way button but it only need to be press up and down to On and Off it.