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| This is the MK I. On the Left is the cable tester with the red LED. On the right is the polarity and power indicator with a diffused green/red LED. Notice the wrong "Tester" spelling on the picture on the left. Its to mark as my own personal tester. | As you can see, the MK I is a very simple device, powered by a 9volt battery. Later on, I realised I could have used 3 volt batteries instead and this could make the whole device slimmer but I never did. |
When I started out in the CCTV business, I encountered a lot of problems when it comes to troubleshooting the cabling. The problems (at that time) were mainly isolated to faulty power supplies and badly crimped RG59 connectors. Because the CCTV camera is (always) never near the DVR unit, its very time consuming to walk up and down checking the two ends. And so, I created the simple CCTV tester. The CCTV tester mainly does two things, which is to test the polarity of the supplied DC voltage and also, the status of the cable. But most important of all, it saves me a lot of time in the field.
This test is to detemine if there is power coming from the Power supply unit for the camera. It also indicates if the D.C. voltage present is of the correct polarity. If its green, the polarity is correct and if its red, the polarity is wrong. In order to test both problems, all I need to do is to just plug it the adaptor's jack into the tester and observe the dual-colour LED.
This section of the tester is to test the status of the cable, whether it is shorting, disconnected or if there was a mistake during termination of the cables. And to test the cable, I just plug it in at one end of the cable and go to the other end and short it. If the LED does not light up while I was shorting the cable, then there is a problem.
As the customer base grew, installing and servicing the CCTV system must always be completed in the shortest time possible. And as we service more and more customers, it was discovered that the MK I Tester is very limited. Feedback from the field confirmed this and they are:-
- Unable to verify the voltage of the camera's power supply unit
- Unable to verify the degree of damage to the camera (or verify if the cable is at fault)
- Unable to assist the installer (alone or even show to the customer) on site in adjusting and aligning the camera during installation
- Unable to demonstrate to the customer possible CCTV points prior to installation.
- Also to reduce the voltage in cable tester to less than 2 volts to minimise equipment damage should it be used improperly.
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| One of the main problem of the MK I was the stress induced at the solder joint as shown in the picture above. I should have left the cable longer from the hot melt glue so that it can absorb more shocks during transport or when it falls to the ground. |