أبسط جهاز لحساب التردد بالهيرتز

أبسط جهاز لحساب التردد بالهيرتز

ربما يكون هذا أبسط مقياس تردد مبني على متحكم دقيق ATtiny2313. يسمح لك بقياس الترددات حتى 10 ميجاهرتز في أربعة نطاقات مبدلة تلقائيًا. النطاق الأصغر لديه دقة 1 هرتز.

مواصفات عداد التردد

• النطاق 1: 9.999 كيلوهرتز ، الدقة 1 هرتز.

• النطاق 2: 99.99 كيلو هرتز ، دقة تصل إلى 10 هرتز.

• النطاق 3: 999.9 كيلوهرتز ، دقة تصل إلى 100 هرتز.

• النطاق 4: 9999 كيلو هرتز ، دقة تصل إلى 1 كيلو هرتز.

وصف عداد التردد على متحكم

يعمل متحكم Attiny2313 من كريستالة خارجية بتردد يصل إلى 20 ميجاهرتز (هذا هو أقصى تردد مسموح به). يتم تحديد دقة مقياس التردد من خلال دقة الكوارتز. يجب أن يكون الحد الأدنى لنصف طول الإشارة المراد قياسها أطول من فترة المذبذب الكرستالي (وهذا بسبب بنية المتحكمة ATtiny2313). لذلك ، فإن 50 بالمائة من التردد المولد هو 10 ميجاهرتز (هذه هي القيمة القصوى للتردد المراد قياسه).

يتم تغذية إشارة الإدخال من خلال المقاومة R9 إلى دبوس 9 من وحدة التحكم الدقيقة. يتم العد باستخدام عداد 16 بت. يزيد التدفق الزائد من تسجيل 8 بت عن طريق الكتابة إلى متغير 24 بت. علاوة على ذلك ، يتم تحويل هذه القيمة إلى قيمة عشرية ويتم عرضها على قطاعات LED.

يتم دائمًا عرض جميع قيم الترددات المقيسة بوحدة kHz. يؤدي اختيار النطاق التلقائي إلى تغيير موضع العلامة العشرية. معدل تحديث البيانات هو 1 هرتز.
يتم استخدام مؤشر LED مكون من أربعة أرقام لعرض التردد المقاس. ترتبط كاثودات مؤشر LED بالمنفذ B ، والأنودات إلى المنفذ D. نظرًا لوضع تعدد الإرسال لعرض المعلومات ومؤشر Super Bright ، ليست هناك حاجة لاستخدام الترانزستورات الرئيسية لتقليل الحمل على منافذ متحكم. 

تردد تعدد الإرسال هو 156.25 هرتز. يمكنك تطبيق مؤشر CA56-12SRWA. المقاومات R1… R8 تحد من التيار المتدفق (يجب ألا تزيد عن 40 مللي أمبير).
يعمل مقياس التردد هذا بمصدر 5V مستقر ، مبني على منظم متكامل 78L05.

تثبيت الفيوزات على المتحكم (في PonyProg):

فحص تشغيل عداد التردد فيبرنامج  Proteus:

Download firmware and model in Proteus

راوابط مفيدة جدا

3-Admiral Wave metal detector.

https://simplemetaldetector.com/induction-balance-metal-detectors/admiral-wave-metal-detector/

4-Android Bluetooth RGB controller LED strip

https://simplemetaldetector.com/simple-diy-projects/android-bluetooth-rgb-controller-led-strip/

5-Arduino Digital Multimeter

https://simplemetaldetector.com/simple-diy-projects/arduino-digital-multimeter/

6-Arduino HDD Motor Driving

https://simplemetaldetector.com/simple-diy-projects/arduino-hdd-motor-driving/

7-Arduino Nano Metal Detector

https://simplemetaldetector.com/pulse-induction-metal-detectors/arduino-metal-detector/

8-AVR Parallel Programming 1

https://simplemetaldetector.com/programmers/avr-parallel-programming-1/

9-AVR Parallel Programming 2

https://simplemetaldetector.com/programmers/avr-parallel-programming-2/

10-AVR serial programmer

https://simplemetaldetector.com/programmers/avr-serial-programmer/

11-AVR Serial programmer 2

https://simplemetaldetector.com/programmers/serial-programmer-2/

12-AVR-910 programmer

https://simplemetaldetector.com/programmers/avr-910-programmer/

13-Basket Coil for Pulse Induction

https://simplemetaldetector.com/search-coils/spider-coil-for-pulse-induction/

14-Batteries , Download

https://simplemetaldetector.com/batteries-and-chargers/batteries-download/

15-Batteries and Chargers

https://simplemetaldetector.com/batteries-and-chargers/batteries-and-chargers/

16-Capacitor ESR measurement circuit (NE555)

https://simplemetaldetector.com/simple-diy-projects/capacitor-esr-measurement-circuit-ne555/

17-Chance PI assembling

https://simplemetaldetector.com/pulse-induction-metal-detectors/chance-pi-metal-detector/chance-pi-assembling/

18-Chance PI download files

https://simplemetaldetector.com/pulse-induction-metal-detectors/chance-pi-metal-detector/chance-pi-download-files/

19-Chance PI metal detector

https://simplemetaldetector.com/pulse-induction-metal-detectors/chance-pi-metal-detector/chance-pi-metal-detector/

20-Chance PI Partlist

https://simplemetaldetector.com/pulse-induction-metal-detectors/chance-pi-metal-detector/chance-pi-partlist/

21-Chance PI PCBs

https://simplemetaldetector.com/pulse-induction-metal-detectors/chance-pi-metal-detector/chance-pi-pcbs/

22-Chance PI programming

https://simplemetaldetector.com/pulse-induction-metal-detectors/chance-pi-metal-detector/chance-pi-programming/

23-Chance PI schematic

https://simplemetaldetector.com/pulse-induction-metal-detectors/chance-pi-metal-detector/chance-pi-schematic-and-pcbs/

24-Charging Li-ion batteries

https://simplemetaldetector.com/batteries-and-chargers/charging-li-ion-batteries/

25-Clone PI-AVR assembling

https://simplemetaldetector.com/pulse-induction-metal-detectors/clone-pi-avr-metal-detector/clone-pi-avr-assembling/

26-Clone PI-AVR Menu

https://simplemetaldetector.com/pulse-induction-metal-detectors/clone-pi-avr-metal-detector/clone-pi-avr-menu/

27-Clone PI-AVR Metal Detector

https://simplemetaldetector.com/pulse-induction-metal-detectors/clone-pi-avr-metal-detector/clone-pi-avr-metal-detector/

28-Clone PI-AVR Parts List

https://simplemetaldetector.com/pulse-induction-metal-detectors/clone-pi-avr-metal-detector/clone-pi-avr-parts-list/

29-Clone PI-AVR PCBs

https://simplemetaldetector.com/pulse-induction-metal-detectors/clone-pi-avr-metal-detector/clone-pi-avr-pcbs/

30-Clone PI-AVR Programming

https://simplemetaldetector.com/pulse-induction-metal-detectors/clone-pi-avr-metal-detector/clone-pi-avr-programming/

31-Clone PI-AVR Schematic

https://simplemetaldetector.com/pulse-induction-metal-detectors/clone-pi-avr-metal-detector/clone-pi-avr-schematic/

32-Clone PI-W Assembling

https://simplemetaldetector.com/pulse-induction-metal-detectors/clone-pi-w-metal-detector/clone-pi-w-assembling/

33-Clone PI-W Buttons function

https://simplemetaldetector.com/pulse-induction-metal-detectors/clone-pi-w-metal-detector/clone-pi-w-buttons-function/

34-Clone PI-W files

https://simplemetaldetector.com/pulse-induction-metal-detectors/clone-pi-w-metal-detector/clone-pi-w-files/

35-Clone PI-W Metal Detector

https://simplemetaldetector.com/pulse-induction-metal-detectors/clone-pi-w-metal-detector/clone-pi-w-metal-detector/

36-Coil calculation

https://simplemetaldetector.com/search-coils/coil-calculation/

37-Coil DD for induction balance metal detectors

https://simplemetaldetector.com/search-coils/coil-dd-for-induction-balance-metal-detectors/

38-Concentric coil for IDX Pro/TGSL

https://simplemetaldetector.com/search-coils/concentric-coil-for-idx-pro/

39-Confirm Subscription

https://simplemetaldetector.com/confirm-subscription/

41-DIY Metal Detector based Arduino

https://simplemetaldetector.com/pulse-induction-metal-detectors/diy-metal-detector-based-arduino/

42-DIY simple obstacle avoiding car (diagram and source code)

https://simplemetaldetector.com/simple-diy-projects/obstacle-avoiding-car/

43-FelezJoo Discrimination Fix

https://simplemetaldetector.com/pulse-induction-metal-detectors/felezjoo-pi-metal-detector/felezjoo-discrimination-fix/

44-FelezJoo Partlist

https://simplemetaldetector.com/pulse-induction-metal-detectors/felezjoo-pi-metal-detector/felezjoo-partlist/

45-FelezJoo PCB

https://simplemetaldetector.com/pulse-induction-metal-detectors/felezjoo-pi-metal-detector/felezjoo-pcb/

46-FelezJoo PI Air Test

https://simplemetaldetector.com/pulse-induction-metal-detectors/felezjoo-pi-metal-detector/felezjoo-pi-air-test/

47-FelezJoo PI assembly

https://simplemetaldetector.com/pulse-induction-metal-detectors/felezjoo-pi-metal-detector/felezjoo-pi-assembly/

48-FelezJoo PI Download files

https://simplemetaldetector.com/pulse-induction-metal-detectors/felezjoo-pi-metal-detector/felezjoo-pi-download-files/

-FelezJoo PI Ground Test

https://simplemetaldetector.com/pulse-induction-metal-detectors/felezjoo-pi-metal-detector/felezjoo-pi-ground-test/

50-FelezJoo PI Metal Detector

https://simplemetaldetector.com/pulse-induction-metal-detectors/felezjoo-pi-metal-detector/felezjoo-pi-metal-detector/

51-FelezJoo PI Programming

https://simplemetaldetector.com/pulse-induction-metal-detectors/felezjoo-pi-metal-detector/felezjoo-pi-programming/

52-FelezJoo PI System settings

https://simplemetaldetector.com/pulse-induction-metal-detectors/felezjoo-pi-metal-detector/felezjoo-pi-system-settings/

53-FelezJoo Schematic

https://simplemetaldetector.com/pulse-induction-metal-detectors/felezjoo-pi-metal-detector/felezjoo-schematic/

54-Generalities about DIY metal detector

https://simplemetaldetector.com/pulse-induction-metal-detectors/generalities-about-diy-metal-detector/

55-GOLDEN MASK 4 pro

https://simplemetaldetector.com/pulse-induction-metal-detectors/golden-mask-4-pro/

56-Hammerhead PI metal detector

https://simplemetaldetector.com/pulse-induction-metal-detectors/hammerhead-pi-metal-detector/

57-Home page

https://simplemetaldetector.com/uncategorized/home-page/

58-IDX Pro Download files

https://simplemetaldetector.com/pulse-induction-metal-detectors/idx-pi-metal-detector/idx-pro-download-files/

59-IDX Pro PCBs

https://simplemetaldetector.com/pulse-induction-metal-detectors/idx-pi-metal-detector/idx-pro-pcbs/

60-IDX Pro PI Metal Detector

https://simplemetaldetector.com/pulse-induction-metal-detectors/idx-pi-metal-detector/idx-pro-pi-metal-detector/

61-IDX Pro schematic

https://simplemetaldetector.com/pulse-induction-metal-detectors/idx-pi-metal-detector/idx-pro-schematic/

62-JTAG Basics

https://simplemetaldetector.com/programmers/jtag-basics/

63-KROT Download files

https://simplemetaldetector.com/pulse-induction-metal-detectors/krot2-metal-detector/krot-download-files/

64-KROT2 Download files

https://simplemetaldetector.com/pulse-induction-metal-detectors/krot2-metal-detector/krot2-download-files/

65-KROT2 Menu Settings

https://simplemetaldetector.com/pulse-induction-metal-detectors/krot2-metal-detector/krot2-menu-settings/

66-KROT2 Partlist Z79

https://simplemetaldetector.com/pulse-induction-metal-detectors/krot2-metal-detector/krot2-partlist/

67-KROT2 Partlist Z80

https://simplemetaldetector.com/pulse-induction-metal-detectors/krot2-metal-detector/krot2-partlist-z80/

68-KROT2 PI Metal Detector

https://simplemetaldetector.com/pulse-induction-metal-detectors/krot2-metal-detector/krot2-pi-metal-detector/

69-KROT2 PI PCB

https://simplemetaldetector.com/pulse-induction-metal-detectors/krot2-metal-detector/krot2-pi-pcb/

70-KROT2 PI Schematic

https://simplemetaldetector.com/pulse-induction-metal-detectors/krot2-metal-detector/krot2-pi-schematic/

71-LC METER

https://simplemetaldetector.com/simple-diy-projects/lc-meter/

72-List of Posts

https://simplemetaldetector.com/list-of-posts/

73-List of posts

https://simplemetaldetector.com/list/list-of-posts/

74-LM2596 regulated power supply

https://simplemetaldetector.com/programmers/lm2596-regulated-power-supply/

75-LM317 Charger(3,7V)

https://simplemetaldetector.com/batteries-and-chargers/lm317-charger-schem-137v/

ps://simplemetaldetector.com/uncategorized/login/

79-LP2951 Charger

https://simplemetaldetector.com/batteries-and-chargers/lp2951-charger/

80-LTC1734 Charger

https://simplemetaldetector.com/batteries-and-chargers/ltc1734-charger/

81-LTC4054 Charger

https://simplemetaldetector.com/batteries-and-chargers/ltc4054-charger/

82-MAX1551 Charger

https://simplemetaldetector.com/batteries-and-chargers/max1551-charger/

83-MCP73831 Charger

https://simplemetaldetector.com/batteries-and-chargers/mcp73831-charger/

85-Metal Detector BT1e

https://simplemetaldetector.com/induction-balance-metal-detectors/metal-detector-bt1e/

86-Metal Detector Circuit

https://simplemetaldetector.com/induction-balance-metal-detectors/metal-detector-circuit/

87-Metal Detector Discrimination

https://simplemetaldetector.com/pulse-induction-metal-detectors/metal-detector-discrimination/

88-Metal detector on Arduino Pro Mini

https://simplemetaldetector.com/pulse-induction-metal-detectors/metal-detector-on-arduino-pro-mini/

89-Metal detector PI Polonese

https://simplemetaldetector.com/pulse-induction-metal-detectors/metal-detector-pi-polonaise/

90-Metal detector Qasar AVR microcontroller

https://simplemetaldetector.com/induction-balance-metal-detectors/metal-detector-qasar-avr-microcontroller/

91-NCP1835 Charger

https://simplemetaldetector.com/batteries-and-chargers/ncp1835-charger/

92-Oscilloscope from a smartphone

https://simplemetaldetector.com/related-techniques/oscilloscope-from-a-smartphone/

94-PI polonese AFRICA V4

https://simplemetaldetector.com/pulse-induction-metal-detectors/pi-polonese_africa_v4/

95-PI-W PCB

https://simplemetaldetector.com/pulse-induction-metal-detectors/clone-pi-w-metal-detector/pi-w-bcb/

96-PI-W Partlist

https://simplemetaldetector.com/pulse-induction-metal-detectors/clone-pi-w-metal-detector/pi-w-partlist/

97-PI-W Schematic

https://simplemetaldetector.com/pulse-induction-metal-detectors/clone-pi-w-metal-detector/pi-w-schematic/

98-PIM-2 Pulse assembly

https://simplemetaldetector.com/pulse-induction-metal-detectors/pim-2-pi-metal-detector/pim-2-pulse-assembly/

99-PIM-2 Pulse download files

https://simplemetaldetector.com/pulse-induction-metal-detectors/pim-2-pi-metal-detector/pim-2-pulse-download-files/

100-PIM-2 Pulse Metal Detector

https://simplemetaldetector.com/pulse-induction-metal-detectors/pim-2-pi-metal-detector/pim-2-pulse-metal-detector/

101-PIM-2 Pulse Partlist

https://simplemetaldetector.com/pulse-induction-metal-detectors/pim-2-pi-metal-detector/pim-2-pulse-partlist/

102-PIM-2 Pulse PCBs

https://simplemetaldetector.com/pulse-induction-metal-detectors/pim-2-pi-metal-detector/pim-2-pulse-pcbs/

103-PIM-2 Pulse schematic

https://simplemetaldetector.com/pulse-induction-metal-detectors/pim-2-pi-metal-detector/pim-2-pulse-schematic/

104-Pinpointer FM-2 v2

https://simplemetaldetector.com/pinpointers/pinpointer-fm-2-v2/

105-Pinpointer G-NOME

https://simplemetaldetector.com/pinpointers/pinpointer-g-nome/

106-Pinpointer KB_V3_VCO

https://simplemetaldetector.com/pinpointers/pinpointer-kb_v3_vco/

107-Pinpointer MINIMAX-PP-II

https://simplemetaldetector.com/pinpointers/pinpointer-minimax-pp-ii/

108-Pinpointer Velleman k7102

https://simplemetaldetector.com/pinpointers/pinpointer-velleman-k7102/

109-Pirate PI assembly

https://simplemetaldetector.com/pulse-induction-metal-detectors/pirate-pi-metal-detector/pirate-pi-assembly/

110-Pirate PI download page

https://simplemetaldetector.com/pulse-induction-metal-detectors/pirate-pi-metal-detector/pirate-pi-download-page/

111-Pirate PI metal detector

https://simplemetaldetector.com/pulse-induction-metal-detectors/pirate-pi-metal-detector/pirate-pi-metal-detector/

112-Pirate PI Partlist

https://simplemetaldetector.com/pulse-induction-metal-detectors/pirate-pi-metal-detector/pirate-pi-partlist/

113-Pirate PI PCBs

https://simplemetaldetector.com/pulse-induction-metal-detectors/pirate-pi-metal-detector/pirate-pi-pcbs/

114-Pirate PI Pulse metal detector

https://simplemetaldetector.com/pulse-induction-metal-detectors/pirate-pi-pulse-metal-detector/

115-Pirate PI Schematic

https://simplemetaldetector.com/pulse-induction-metal-detectors/pirate-pi-metal-detector/pirate-pi-schematic/

117-Programing a new ATmega328p with Arduino

https://simplemetaldetector.com/programmers/programing-a-new-atmega328p-with-arduino/

118-Programmer for PIC

https://simplemetaldetector.com/programmers/programmer-for-pic/

119-Programmers

https://simplemetaldetector.com/programmers/programmers-for-microcontroller/

120-Programmers utilities

https://simplemetaldetector.com/programmers/programmers-utilities/

121-Pulse detector Minipuls-3

https://simplemetaldetector.com/pulse-induction-metal-detectors/pulse-detector-minipuls-3/

122-Pulse Induction coil 1

https://simplemetaldetector.com/search-coils/pulse-induction-coil-1/

123-Pulse Induction coil 2

https://simplemetaldetector.com/search-coils/pulse-induction-coil-2/

124-Pulse Induction Metal Detectors

https://simplemetaldetector.com/pulse-induction-metal-detectors/pulse-induction-metal-detectors/

125-Pulse metal detector “Pirate”

https://simplemetaldetector.com/pulse-induction-metal-detectors/pulse-metal-detector-pirate/

126-Pulse Metal Detector on Arduino

https://simplemetaldetector.com/pulse-induction-metal-detectors/pulse-metal-detector-on-arduino/

127-Pulse metal detector Tiny

https://simplemetaldetector.com/pulse-induction-metal-detectors/pulsdetektor-tiny/

128-Pulse PI-AR metal detector based on STM32f1

https://simplemetaldetector.com/pulse-induction-metal-detectors/pulse-pi-ar-metal-detector-based-on-stm32f1/

129-Radar prototype using ultrasonic sensors and Arduino

https://simplemetaldetector.com/arduino-projects/radar-prototype-using-ultrasonic-sensors-and-arduino/

132-Sample Pinpointer

https://simplemetaldetector.com/pinpointers/sample-pinpointer/

133-Schatzsuche mit Metalldetektoren

https://simplemetaldetector.com/pulse-induction-metal-detectors/schatzsuche-mit-metalldetektoren/

134-Search coils

https://simplemetaldetector.com/search-coils/searchcoils/

135-SIGNAL LEVEL INDICATOR LED FOR METAL DETECTOR

https://simplemetaldetector.com/pulse-induction-metal-detectors/signal-level-indicator-led-for-metal-detector/

136-Simple Metal Detector

https://simplemetaldetector.com/

137-Simple metal detector

https://simplemetaldetector.com/pulse-induction-metal-detectors/simple-and-reliable-do-it-yourself-metal-detector/

138-Simple metal detector for beginners needs only TL074

https://simplemetaldetector.com/induction-balance-metal-detectors/simple-metal-detector-for-beginners-need-only-tl074/

139-simple metal detector with 2 NE555

https://simplemetaldetector.com/induction-balance-metal-detectors/simple-metal-detector-with-2-ne555/

140-SIMPLE METAL DETECTOR WITH DISCRIMINATION

https://simplemetaldetector.com/pulse-induction-metal-detectors/simple-metal-detector-with-discrimination/

141-Simple PI coil for pulsed metal detector

https://simplemetaldetector.com/search-coils/simple-pi-coil-for-pulsed-metal-detector/

142-Smart Hunter Metal Detector on a Smartphone

https://simplemetaldetector.com/pulse-induction-metal-detectors/smart-hunter-metal-detector-on-a-smartphone/

143-Spider coil

https://simplemetaldetector.com/search-coils/spider-coil/

144-Spirit PI wireless metal detector based Arduino

https://simplemetaldetector.com/pulse-induction-metal-detectors/spirit-pi-wireless-metal-detector-based-arduino/

145-SurfPI Pro metal detector

https://simplemetaldetector.com/pulse-induction-metal-detectors/surfpi-pro-metal-detector/

146-Terminator 3 metal detector

https://simplemetaldetector.com/pulse-induction-metal-detectors/terminator-3-metal-detector/terminator-3-metal-detector/

147-Tesoro Eldorado Metal detector

https://simplemetaldetector.com/vlf-metal-detectors/tesoro-eldorado-metal-detector/

148-Tesoro Golden Sabre Light “TGSL”

https://simplemetaldetector.com/induction-balance-metal-detectors/tesoro-golden-sabre-light-tlsl/

149-Tesoro Lobo metal detector

https://simplemetaldetector.com/induction-balance-metal-detectors/tesoro-lobo-metal-detector/

150-The simplest frequency meter

https://simplemetaldetector.com/simple-diy-projects/the-simplest-frequency-meter/

151-TL12000 metal detector

https://simplemetaldetector.com/pulse-induction-metal-detectors/tl12000-metal-detector/

152-Toner Transfer PCB method

https://simplemetaldetector.com/related-techniques/toner-transfer-pcb-method/

153-TP4056 Charger

https://simplemetaldetector.com/batteries-and-chargers/tp4056-charger/

154-Tracker PI-2 metal detector

https://simplemetaldetector.com/pulse-induction-metal-detectors/tracker-pi-2-metal-detector/

155-Turn your iPhone into a metal detector

https://simplemetaldetector.com/pulse-induction-metal-detectors/turn-your-iphone-into-a-metal-detector/

156-Universal Charger PIC16F877A

https://simplemetaldetector.com/batteries-and-chargers/universal-charger-pic16f877a/

157-USBasp Atmel Programmer

https://simplemetaldetector.com/programmers/usbasp-atmel-programmer/

158-USBasp TQFP32 Version

https://simplemetaldetector.com/programmers/usbasp-programmer-tqfp32-version/

159-USBTiny-MkII Slim AVR

https://simplemetaldetector.com/programmers/usbtiny-mkii-slim-avr/

161-VINTIK-PI V1 metal detector

https://simplemetaldetector.com/pulse-induction-metal-detectors/vintik-pi-v1-metal-detector/

162-VINTIK-PI V2 assembly

https://simplemetaldetector.com/pulse-induction-metal-detectors/vintik-2-pi-metal-detector/vintik-pi-assembly/

163-VINTIK-PI V2 download page

https://simplemetaldetector.com/pulse-induction-metal-detectors/vintik-2-pi-metal-detector/vintik-pi-download-page/

164-VINTIK-PI V2 metal detector

https://simplemetaldetector.com/pulse-induction-metal-detectors/vintik-2-pi-metal-detector/vintik-pi-metal-detector/

165-VINTIK-PI V2 partlist

https://simplemetaldetector.com/pulse-induction-metal-detectors/vintik-2-pi-metal-detector/vintik-pi-partlist/

166-VINTIK-PI V2 PCBs

https://simplemetaldetector.com/pulse-induction-metal-detectors/vintik-2-pi-metal-detector/vintik-pi-pcbs/

167-VINTIK-PI V2 schematic

https://simplemetaldetector.com/pulse-induction-metal-detectors/vintik-2-pi-metal-detector/vintik-pi-schematic/

168-VLF Madera metal detector

https://simplemetaldetector.com/induction-balance-metal-detectors/vlf-madera-metal-detector