laxman3018
New Member
but i ma not from elctronic background so i cant understand that datasheet....pls tell how to connect....???
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so what shud i doNo Ron.
The 555 uses a HUGE 100uF timing capacitor so it turns on and off at a few Hz. The buzzer makes the tone.
But the metal detector transistor continuously oscillates and holds the 555 always turned off.
A metal detector is supposed to detect the frequency change when metal gets near the coil. This circuit does not detect a frequency change.
yes it work i have tested it when any metal comes it start beeping sound...Does the metal detector work or not work? Please say, "Yes it works" or "No it does not work".
The datasheet for the RF Tx and Rx shows exactly how to connect them.
the circuit works fine iwant to conect it with rf module. that i can get signal wireless like led glows on reciever side thats it but how shud i connect it with given circuitWhether or not the posted circuit oscillates is critically dependent on the coil inductance, according to LTspice. So it can act as a metal detector if the trimmer is set such that the circuit is on the threshold of oscillation.
iF i connect that pin 4 to my TE pin of encoder will it work????
i dont know all about that becoz..i am not from electronic background....so i cant understand all that things...I think the metal simply shorts the terminals on the coil.
Don't you think the coil has more inductance and a higher Q when it has a core made from nearby ferrous material? Then it is MORE likely to oscillate?
Oh, the circuit is a brass detector that reduces its inductance and Q? Then the oscillation stops?
yes i want only one led to glow when metal detects(wireless)I told you, pin 4 of the 555 is the RST. While pin 4 is held low the 555 will not oscillate. Look at the circuit and understand how it works. So you have a signal in the circuit to pin 4 of the 555 correct? When that signal is high metal is detected and when it is low there is no metal detected. So th signal to pin 4 of the 555 needs to be inverted, use a transistor like a 2N2222 or 2N3904 to drive the HT 12E pin 14.
Now on the HT12E pin 14 is the transmit enable pin. When pin 14 is low the /TE is enabled. Read the data sheet for the HT 12E and understand how it works.
You don't really need the HT 12E for this. You only want to light a single LED as I read it but your choice.
Ron
yes i want only one led to glow when metal detects(wireless)
i have both RF modules and HT12e,d encoder decoder...
MY friend told me about BC547 register and told to connect like this...
Take pin 3 from
metal detector, give to base of transistor with 10k resistor. emitter
is grounded. connect RF trasmitter pin to collector. then collector
is connected to 5v with a 10k resistor.
circuit image is down..
will this work????
how much resistor should i use at base???Yes, that will work.When the base is low the out collector) is high. That is what you want to enable the encoder. You may need to reduce the base resistor but that is what you want.
Ron
both resister shud be 2.3 or 3.3k...?????I would start with 10K as shown and work down. Actually around 2.2 K or 3.3 K should work fine.
Ron
No Ron.
The 555 uses a HUGE 100uF timing capacitor so it turns on and off at a few Hz. The buzzer makes the tone.
But the metal detector transistor continuously oscillates and holds the 555 always turned off.
A metal detector is supposed to detect the frequency change when metal gets near the coil. This circuit does not detect a frequency change.
The 555 uses a HUGE 100uF timing capacitor so it turns on and off at a few Hz.
when metal present than it start beeping and when not then beeping sound goes offf....
Due on the 24th that does not give you much time.its my college project already name is submitted and demo is on 24th and its not working