Adafruit Feather Transmitters

WiFi Training Transmitter

One of the toughest transmitters to direction find is that of an unauthenticated, WiFi client. Without being attached to an access point, a WiFi client may only send out a transmission, or probe request, once every 5 minutes. It is not uncommon to see requests sent every 20 minutes. There are ways to expedite the …

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Duty Cycle Oscope

Adjust the Duty Cycle of the 555 Timer without Changing the Frequency

This tutorial explains how to control the duty cycle of the 555 timer’s output. Not only does this design control the duty cycle but the frequency remains relatively stable during the adjustment. This is helpful for a number of applications such as working with pulse width modulation. Schematic: Formulas in the Video:

Bugging DeviceBugging Device

Hiring a Proficient Bugsweep Team

Before we get started, you should know I am not pushing my own bug sweeping services. I do not sell my services commercially. I have 15 years of experience in technical surveillance countermeasures (TSCM) and am often called upon to give advice regarding many aspects of this profession. I gain nothing from this article other …

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Wireshark VoIP Challenge

Knock off those network analysis cobwebs by downloading the file below and taking part in the Wireshark VoIP challenge. This a a short capture but a tricky one. Wireshark PCAP File MD5 Hash: 139b7dfea64ee097a4a415ba320cc5b6 The Challenge I’m currently putting together a new VoIP class and came across a nasty little Linux program that can manipulate VoIP …

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