Let's Make Robots!

TB-007 Metal Detector

Gareth's picture

TB-007 (ThunderBird 7) Big Brother of TB-6. (Blogged)

TB-007 is able to Detect Metal  (Coins, Rings, Gold, Electric Underground/Floor Cables and annoying Bottle Tops)

Improved Traction Design - aimed to cross over Stones and Sand.

I totally redesigned the Chassis of TB6 to make it more robust.

1st Video Shows it in Action. (-: towards the end are some Outakes :-)

2nd Video :- PolyMorph SkidSteer Helper ©

  TB007New_011small2.jpg

 

Here TB-007 has been fitted with a Wireless Camera -

so i can sit in my deck chair and watch its progress should it wander off.

The Camera is mounted to a servo which also has a Laser pointer attached (see main picture)  -

During "Fine Detect" phase of software loop, the servo positions itsself to look

and pinpoint with laser and Video the exact location of Metal Found.

TB_007VideoCamsmall.jpg

 

The underside shows the layout of the Motors and a new PolyMorph SkidTurn Helper ©

TB007Undersidesmall.jpg

 

Here is the  PolyMorph SkidTurn Helper © in more detail - In the Down Position.

TB007SusDownsmall.jpg

 

 In the Up Position.

It is a hollow Poly-Morph "Thingy" which is connected to a servo - when activated it lifts the whole back end up into the air.

Then the front wheels can turn in opposite directions and the "Thingy" slides -

allowing TB-007 to turn effortlessly on the Spot - over the ground (polymorph is very smooth).

  TB007SusUPsmall.jpg

 

The BirdsNest (Thunder) ---- not so pretty but hey it works -

i have to install a second Voice Arduino so i have not finalised the layout

(-: velco straps are magic for rapid proto-typing :-)

TB-007 is Arduino Based with a Motor Shield (that controls the 2 main motors - 1 stepper motor and 3 Servos)

TB007Birdsnestsmall.jpg

 

Here are TB-007s Test Coins -

The 5 Cent Silver American Indian coin known as the "Buffalo" is my Favorite.

The 500Lira (in video) and 10F (silver/bronze ringed) coins have the best detect signal.

TB007Coinssmall.jpg



The Metal Detect Electronics have be Hacked out of a Hand Held Metal Detector.

MentalDetective1__4_.jpg

The Metal Detector consists of 2 separate detetor coils wound around a ferrite rod.

 The Circuit is a Beat Frequency Oscillator - able to detect metal and also live electrical cable.

  The Beat-frequency oscillator (BFO) is the simplest type of metal detector.

The basic beat-frequency metal detector employs two radio frequency oscillators which are tuned near the same frequency. The first is called the search oscillator and the other is called the reference oscillator.

The outputs of the two oscillators are fed into a mixer which produces a signal that contains the sum and difference frequency components. This signal is feed to a low-pass filter removing the harmonics. As long as the two oscillators are tuned to the same frequency, the output will have no signal.

When a metallic object disturbs the magnetic field of the search coil, the frequency of the search oscillator shifts slightly and the detector will produce a signal in the audio frequency range.

MentalDetective1__6_.jpg

 

 

TotoroYamada's picture

Insane...

...that's just insane! As always, great bot Gareth!

And i can't believe you have a 10F coin, those ones haven't been in use for about 8-9 years!

 

Gareth's picture

I am an Avid Coin Collector

I have always collected coins  since "i was knee-high-to-a-grass-hopper" and now my son has caught the bug.

Each Coin has its own Metal Signature which i hope to program into the software.

By the way the double ring metal coins like the 10F (french) have a very strong wide signal. (so it may wander in your direction)

TotoroYamada's picture

And now all euro coins have

And now all euro coins have those double metal ring so indeed your robot might leave your country...
Gareth's picture

Metal Coins have different characteristics

 I hope to check and graph my "test coins" shortly - here is an example of an English 50p coin.

Its pretty non-linear, so far - each coin (under test conditions) gives a different response.

MentalDetectivegraph.jpg

Gareth's picture

TB-007 (ThunderBird 7) Big Brother of TB-6.

After totally upgrading "ThunderBird 6"s chassis i decided that enough things had been altered to give TB-007 his own robot spot.

Web Cam has been Fitted along with a targeting Laser.

PolyMorph SkidTurn © device also installed -

If you have a robot that cannot turn on a carpet then this is a cool idea (see Video of it in action).

CaptainTuna's picture

the PolyMorph SkidTurn

the PolyMorph SkidTurn © is great stuff A very nice idea, good job on that one!

 

Ian_K's picture

Gareth your inginuity and

Gareth your inginuity and ideas never cease to amaze me! Nice bot and professional looking too! I hope that some point I am able to build robots this nice and to this degree. Great job and please do keep up the great work!!
-Gary's picture

Just an Awesome Idea Come to Life

Gareth, Really dig your latest bot! TB6 was cool but you just blew it away with TB7. Do you still use the Stepper motor? I can't say I saw it in operation in the vids. Also, I see that Buffalo nickel in the multiple coin photo. Does it still have a readable date? I have a collection of that coin myself. Did you really find it in Switzerland?

Again, a great looking bot and unique project. Hmmm... With a couple of mods, my next bot could dig up the coins that you find.

Gareth's picture

Buffalo - worth face value only........ ;-(

Yes the stepper motor is still in use though i may have to upgrade to get more travel.

The "Buffalo" is missing the date sadly - i heard it was one of the first USA coins not to have an american president  - and it had design flaw that meant that the soft metal wore quickly .........i have had it for manymany years now.

CaptainObvious's picture

Awesome! I love it! More

Awesome! I love it! More uber leet-hacking-the-world-to-work-for-me!

 

I'm surprised the Military isn't using something of the sort, of course upgraded to their standards.. but would take alot of our troops out of harms way!

 

Are you going to go search for landmines in your backyard, and set their Metal Signature?:D

 

But f'realio! Great job, it's stuff like this that got me interested in electronics! Ultimate DIY!

5 out of 5!

Ha ha ha, thats why the

Ha ha ha, thats why the germans (i think) made their land mines out of glass :s
Gareth's picture

Glass mines

I believe that military detectors will also detect glass too - but with ultrasound........

through sand? i wonder how

through sand? i wonder how youd do that.....
ezekiel181's picture

Wow, awesome! Now you can go

Wow, awesome! Now you can go down the beach and monitor what TB7 is doing from your camp chair. Do you think you have room on the back of the new chassis to put a servo actuated wire scoop?
Gareth's picture

Pondering - scoopy thing !!!!

 Well one idea is using a Hairclip - clueless at the moment how to motivate the dash thing .............

..... Answer on a "Post card"welcome ......

I know that there is enough weight to allow TB007 to activate this under the "sand" a

few centermeters with the help of the  PolyMorphthingy 

TB007hair1.jpg

TB007hair2.jpg

Rudolph's picture

Post card?Maybe a cable

Post card?

Maybe a cable setup would work with that, think bicycle brake cable. Drill a small hole through the middle of each handle for the cable to pass through. The sheath would be stopped by the handle, so when the cable is pulled it'll pull the other handle towards the sheath.

Gareth's picture

Like So - Brake Calipers

 Bicycles are just "Up My Street"  thanks for the "postcard" idea.

TB007feather-profile-comp_0.jpg

 

Rudolph's picture

Cool ;) My feeble attempt to

Cool ;) My feeble attempt to describe a cable's operation was completely unnecessary. Haha.

Wonder if a standard hobby servo has enough gumption to pull the spring in a hair clip?

This could be a new standard in DIY robot grippers! Good idea Gareth. I'm gonna use it someday.

Gareth's picture

I could use this mechanism though----how did i forget....

 This mech-upsidedown with the hairclip instead of paper.

Upgrade to stronger Servo and i would not need the spring return even.

VenusFlyTrap__7_.jpg

Im sure you know how to

Im sure you know how to program it...but have it pull ahead...push down the scoop, open of course...close it..back up...and check to see if it got it.....

All your designs are cool.

All your designs are cool. Except for the Rats Nest :P
Gareth's picture

Rats leaving the Sinking Ship - or rapid prototyping

I prefer to call it "Rapid Prototyping" , well thats my excuse and i am sticking with it...........

.....thanks for the support....

OMG!!! I thought of

OMG!!! I thought of something EXACTILY like this JUST TODAY!! btw we went metal detecting and got like $4.25 in change....
Gareth's picture

There is hope for TB007 then...

I am really new to this Metal Detection bug - since building TB007 i am even more inquisitive - and will be shortly buying a bigger handheld sweepy one so that i can join in the fun ......

Sorry for 2 comments...you

Sorry for 2 comments...you should put flags or some other system on it where, it can mark whatever it finds so you can get off of your computer later and dig up "the booty"!
guibot's picture

Gareth this turns out 5

Gareth this turns out 5 stars!! I would give more stars if I could  :)

Now let the TB-007 go hunt some teasures!!!  ;)

fritsl's picture

PolyMorph SkidSteer Helper

PolyMorph SkidSteer Helper ©

ROFL, freaking brilliant, G!!

Gareth's picture

Yes Ladies and Gentlemens You saw it first on LMR

Yes as soon as my Eureka idea came i dashed direct out of the "bath" to the Copyright office and filed a claim  - much to the excitment of the lady clerk.
TinHead's picture

Ok that is cheating Gareth...

Come on man you already got my 5 stars on 006 ! Leave some for the rest of LMR ;)

Ok, ok, here you go, another 5, keep it up man :D

Where  do you get your ideas? Very cool job with the skid steering polymorph thingie.

 

Gareth's picture

Eureka Bath is the Best Place

I have got into the habit of writing all my ideas down (even on a notepad on my natel) sometimes the most obsure ideas end out practical, so never loose them.

Some ideas just need a little more time in the "cortex" before they are ready to jump out......

Thanks for your Stars - much appreciated

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