Need Little help - Mark Stuart Pulse induction Metal Detector 1

[adiputra]

Hi guys,


Sorry for wrong section but i need an immediate help from you all guys. I need some help in making this metal detector.


IC2 - 40408 binary counter? what kind of this IC used in this project? i try to look out the net for its datasheet, i just found 4040B IC. Can i substitute this ic?
BFY407A diode - can i substitute this diode?
TLC 555 - also can i substitue this IC with NE555?
clock crystals 40 kilohertz - can i use 38 or 32 kilohertz?


if anyone in this forum can help me, i really appreciate it.


Thanks.

[goldfinder]

I suspect the 40408 is a type as there are 4040 chips.

[adiputra]

thanks for your reply,

also i need some clarification these three components, i would like some advice from you if you don't mine.

BFY407A diode - can i substitute this diode with other acceptable diode?
TLC 555 - can i substitute this IC with NE555?
clock crystals 40 kilohertz - can i use 38 or 32 kilohertz?

[goldfinder]

thanks for your reply,

also i need some clarification these three components, i would like some advice from you if you don't mine.

BFY407A diode - can i substitute this diode with other acceptable diode? Yes as long as specs are close.
TLC 555 - can i substitute this IC with NE555? a 555 is the same.
clock crystals 40 kilohertz - can i use 38 or 32 kilohertz?

The PIC is usually driven by a max of 20 KHZ although I have seen a few new ones that go to 40 Khz. I don't know the PIC chip you are using. Check with the manufacturer (Microchip). They have all that data on their website. The only thing you will lose in going down in frequency is response time of the circuit. The crystal drives the PIC clock (instruction time) and reducing the clock time slows down the programing.

[adiputra]

The PIC is usually driven by a max of 20 KHZ although I have seen a few new ones that go to 40 Khz. I don't know the PIC chip you are using. Check with the manufacturer (Microchip). They have all that data on their website. The only thing you will lose in going down in frequency is response time of the circuit. The crystal drives the PIC clock (instruction time) and reducing the clock time slows down the programing.

Thanks for your reply,

I believe the PIC is for the EE Treasure Hunter Pi2 (micro controller metal detector). I was trying to built the EE Tresure Hunter Pi1 - non micro controller. So, could you suggest me which crystal value should i use for this metal detector? Also, it is said that there is a bug in the schematic which i think it happens to the IC1(the connections between pin 12 & 13 should be shorted), the transistors TR2 & TR3 must be swapped -it need to be changed or just change its pins connection? and also the capacitors next to the IC1i2 22pf and in (correct me if i'm wrong). If anyone do have the corrected schematic and PCB diagram for this metal detector it will be great,so i can use it as reference.