Information on ECG machines and their operation is sought for creating a simple wireless ECG device using Bluetooth or RF technology. Resources like HowStuffWorks do not provide direct explanations but offer links to related sites, such as TheMDsite, which focuses on EKG interpretation rather than machine mechanics. A search for "EKG machine electrode circuit" yields valuable results, including a paper titled "A Portable, Low-Power, Wireless Two-Lead EKG System" from Harvard. These resources can assist in understanding the circuitry and functionality of ECG machines. Additional research may be necessary to gather comprehensive information on the subject.