The post details the main specifications and pinout functions of the IC CSA along with other technical aspecst of the chip. The device CSA is a bipolar monolithic IC specifically designed for metal detecting circuit applications. An external LC tank circuit becomes imperative while applying the IC in a metal detector configuration. The externally connected LC circuit in association with the in built oscillator circuit initiates the required oscillations in the circuit in a controlled manner.
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The principle of operation of the proposed metal detector circuit is quite basic yet very interesting. The detecting function is triggered by sensing the decrease in the Q level of the LC network associated with the circuit in the presence of a metal at a specified proximity level. Basically the built-in oscillator of the IC CS is made functional with the inclusion of a parallel resonant LC tuned network in conjunction with a feedback resistor wired up with the OSC and RF pin outs.
The impedance of the tuned resonant network may be expected at the maximum level as long as the driving source frequency is equal to the resonant frequency of the LC circuit network. On detecting the presence of a metallic object at a close proximity to the inductor sensor, the voltage amplitude of the LC network gradually begins to fall corresponding to the closeness of the metal to the inductor. Due to the above factor when the oscillation frame of the chip drops and reaches a certain threshold level, triggers the position of the complementary outputs such that they change states.
Referring to the figure, as soon as a metal object is detected at the inductor input, the capacitor connected to the DEMOD gets charged through an in built current source of 30 uA. However during the detection process the above current gets deviated away from the capacitor proportionately with the generated negative bias on the LC network. When the procedure forces the internal comparator to trip, it switches the transistor which introduces a This resulting reference level then equals near about 1.
The feedback pot connected across the OSC and the RF is used for setting the detection range of the circuit. Increasing the resistance of the pot, in course increases the range of detection and subsequently the tripping point of the outputs. However the detection and the trip points may also be dependant on the LC configuration and the Q of the LC network. The proposed metal detector circuit may be set up initially by following the below described steps:.
Position a metal object at relatively larger distance away from the inductor, assuming the Q of the LC to be at the maximum sensitivity and the distance to be within the allowable range provided by the Q factor of the inductor. With this set up adjust the pot such that the outputs just shift states indicating the detection of the metal object.
Repeat the adjustment procedure by gradually increasing the distance until a suitable maximum sensitivity of the circuit is optimized. Removing or displacing the metal manually should make the output of the circuit to revert states, confirming the perfect working of the circuit. Though the circuit is able to detect metals within a range of 0. The Q factor is directly proportional with the sensitivity of the circuit and the degree of detections.
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How to Make a Simple Metal Detector Using IC CS209A
A uH coil is used to sense the presence of metal. The inductance of the coil change in the presence of metals and the resultant change in oscillation is demodulated to create an alarm. The LED gives a visual indication too. This circuit can sense metals up to a distance of few inches.
Proximity Detector IC CS209A Pinouts – Datasheet Explained
Proximity Detector. The CSA is a bipolar monolithic. The IC see block diagram contains two. The oscillator, along with an external. LC network, provides controlled oscilla-.