Gary’s Pulse Inductive Metal Detector | DIY Homemade Project



Did you know that some “homemade metal detectors” can perform amazing results as compared to some manufactured MD (metal detector) products? One good example is Gary’s very own Pulse Inductive Metal Detector.


Since I am able to build one for myself and used it in our various treasure hunting projects with some good results, I am confident enough to say that Gary’s PI (Pulse Inductive) MD is one of the best MD circuit designs available online. When built correctly, this tool can penetrate deep buried metal objects even exceeding most commercial MD products in the market.

Many MD enthusiasts are actually requesting Gary for his ready-made PI MD. Unfortunately, he does not sell any of his home-built MDs but he does sell electronic kits of his design. This kit consists of all the necessary electronic parts of his PI MD design except for the search coil and casing. The search coil is another separate order while you have to use your own creativity in building its case.

Gary PI MD

If you have some basic knowledge in electronics, the kit comes with a manual complete with easy-to-follow instructions on how to build the circuit yourself. Those with zero knowledge in building electronic projects are advised to seek help from an electronic technician or you can just pay him to build the circuit for you.

Assuming that you bought Gary’s PI MD kit then after your first attempt of building the circuit, it failed to work. If this happens, you can actually contact Gary and send your failed project back to him. He will then troubleshoot and fix everything for you “free of charge”.

On the other hand, if you have good knowledge and skills in building electronic projects then you may just choose to download a copy of Gary’s PI MD schematic circuit diagram on his website. Although, some individuals are complaining about the availability of his circuit’s components. Some components are “obsolete” or no longer available in most Electronic Hobby Shops. But if you know what you are doing, you may find the perfect “replacement” or “substitute” to these missing components. If none then your best option is to contact Gary and order the components that you need.

Basic Tips in Building Gary’s PI MD



Most failures of none-working projects are common basic errors such as incorrect connections, improper soldering and interchanged components. Thus, the best tip is to “always ensure” and “double check” every course of action that you are about to perform on your project.

Here are more basic tips to avoid errors when constructing your own Gary’s PI MD:

1. Working PCB Board Design

If you bought a kit from Gary then the included PCB board is already etched. All you have to do is to connect its electronic components. However, if you are building everything on your own then make sure that the layout of your circuit connections are all correct before etching it on your PCB board. If you want to re-design Gary’s original PCB Board layout then it is strongly suggested to use software programs to avoid any unlikely mistakes on your connections.

Note: PCB board that is included on the kit must be washed and cleaned to make sure that every “flux residue” are removed as this could cause “shorted connections”. After cleaning the PCB board, make sure to dry it before starting to work on it.

2. Double Check your Components

Again, if you purchased Gary’s PI MD kit then you have nothing to worry regarding about its components. But if you are building everything on your own, it is important that you have to double check every components that you buy before checking out from the store. This is due to the reason that some sellers might accidentally give you some wrong values of your purchased components.

When soldering each components on the PCB board, you also need to double check each component to make sure that you are installing them into their correct spots.

3. Solder your Components Safely

Majority of electronic components are vulnerable to extreme heat temperature which could cause damage. Thus, good soldering skill is required. If you do not have the skill then it is best to hire an electronic technician to do it for you.

Recommended soldering tool to be used on this project must have 25 power-wattage rating.

4. Protect the IC by Using IC Sockets

The IC (Integrated Circuit) components are the once that can easily sustain serious damage especially when directly soldered onto the PCB board. Due to this reason, it is highly recommended to use “IC Sockets” for their protection.

Aside from the ICs are the “REG1117A” or “MC33269” which are also sensitive components that can easily get damaged due to extreme heat temperature.

5. Use Non-Metallic Materials for the Casing

You should use non-metallic materials for the construction of your MD’s casing. Some suggested materials includes woods, plastics and fiber glasses.

6. Trial-and-Error with the Search Coil

Gary suggests that you should perform your own experiment with the search coil because it is the main key in achieving deeper penetration of your equipment. This experiment involves trial-and-error with the gauge-size of the coil, number of turns and dimensions.

7. Use Low Current Regulated Power Supply for Testing

It is basically important to use low “current regulated power supply” when testing your nearly completed project. This is to protect its electronic components from any possible errors particularly on their connections. Gary suggests to use a regulated power supply with current ratings of less than 200 mA.

8. Use 10 NiMh Batteries or 12 Volt Lead Sealed Acid Battery

Gary recommends the use of either “10 NiMh batteries” or “12 volt lead sealed acid battery” on his PI MD design. However, he discourages the use of Lithium Ion batteries due to their low voltage ratings which is between 10.8 to 12.6 volts.

Actual Field Test of Gary’s PI Metal Detector



After completing Gary’s PI MD, I performed several actual field tests experiments to check if it could penetrate deep buried objects.

The first field test I performed was on a pop-can buried at a depth of around 1.5 meters. My TM808 commercial metal detector could not detect the object at this depth. But when I used Gary’s PI MD, I was able to detect the buried pop-can with ease by using a 15 inches diameter search coil consisting of 70 to 80 turns.

My succeeding actual field tests were more on smaller size objects such as coins. This is to prove if sizes of search coils could really enhance better detection on certain particular objects.

Using a 1 inch size silver coin, my 15 inches diameter search coil can detect it at a depth of only 3 inches which is pretty bad. I used another smaller object which was a 0.5 inch size copper coin and by using the same search coil again, it was able to detect it for only about 2 inches depth.

I made another search coil with exact same diameter (15 inches) but with 10 turns of windings. Performing the test on the coins yields poor results which is not even worth mentioning on this post but on the pop-can, it can detect this object at a depth of 1.8 meters.

On my third experiment, I made another search coil with smaller size. It consists of only 8 inches diameter with 30 windings. When tested on the same objects above, it has an impressive results in detecting the coins but not on the pop-can. The silver coin was detected at a maximum depth of 12 inches while the copper coin was at 6 inches.

Gary’s Update About his PI MD



None Kit Buyers are no Longer Entertained

Gary will no longer help individuals who did “not bought” his basic PI MD kit from him. This was due to the reason that these people were asking for some certain component as possible substitutes which often the cause of errors or inefficient performance of their projects.

Parts List and PCB Layout were Taken Down

Unfortunately, Gary had taken down the parts list and PCB board layout of his PI MD design. Sorry for the new guys. However, if you are going to buy Gary’s basic kit then included on the package are the printed copies of the schematic, PCB board layout and the parts list of his PI MD design.