Hi Guys, I have bee using a DIY pin pointer and cant fault it, total cost: R600.00.
For those of you in the industrial electronics field you should know about this. I will however try to explain it as best as I can.
The idea is to make up a sensor with a 9 volt battery and a piezo buzzer and a press button switch, so it is only on when you use it. I have used a BANNER inductive sensor with a polar diagram best suited, the range is 20 mm to the front and 10 mm to the side.
These sensors can be obtained at ant industrial supplier, or go to "cym systems" on the Webb. I use the local agent here in Ndbeni in CPT.
I have used a unit with a plug on, the plug allows me to change sensors to alter the range to detect with in sand or water the control box it kept dry at all times the sensors come with 2 meters of cable on them.
The smaller the overall diameter of the sensor the less the range is. Larger sensors can give you up to 30 mm range, it does sense on the side as well.
These inductive sensors can detect any metal being brass, silver, stainless steel, iron etc. They are used for detection in high speed application in industry. Generally they are cheap, it all depend what one calls cheap, but remember there are over two hundred to choose from in size and range.
The best way is to start off with the supply voltage, they range from 12-30 volts DC, but work well from 8,75 volts up to 30 vdc.
Then select the range sensing distance, this can be from 0.5mm to 30mm. once you have this done then select the side sensing range as well.
There are two types flush and none flush as I have shown in the picture.
The sensor is 100% water proof with a plug, there are o-rings in the plug.
Connecting it up is not difficult, one gets a PNP or NPN output. This mean the output is positive or the output is negative, you can use either one just connect up accordingly.
If you have questions please feel free to ask for help. The circuit to connect invokes a battery and a piezo buzzer and a press button switch. Feel free to ask me any questions to assist you, mine has been use for months and never let me down.