Tutorials

WiFi Training Transmitter

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 […]

Adafruit Feather Training Transmitters Update

Adafruit Feather Training Transmitters Update

  In a previous article (which you really should read before going any further), I detailed how one could use a particular transmitter, the Adafruit Feather LoRa 433MHz transmitter, to produce all manner of signaling types. To round out the experience, I’ve bought the other 3 […]

Using the Adafruit Feather for Fun and Training

Using the Adafruit Feather for Fun and Training

“Make us a transmitter for training.” This has been one of the single most requested items since I’ve been in business. Unfortunately, there has been no easy answers. I’ve tried a number of different approaches but nothing seemed robust enough or cost effective enough for […]

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

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 […]

Wireshark VoIP Challenge: Protect the Flow

Wireshark VoIP Challenge: Protect the Flow

The objective of my career has been pretty simple up until recently. Bad guys want information X. Keep bad guys from taking information X. Simple enough. There’s also an Appendix to that objective. Bad guys always want to take information X. Build a program to stop […]

Wireshark VoIP Challenge

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 […]

How to Use a 555 Timer in Monostable Mode

How to Use a 555 Timer in Monostable Mode

It’s been about a year since my last tutorial. Over the last year I learned that teaching in the real world will take away time from teaching in the virtual world. Many people have contacted me asking about a tutorial for the 555 timer in Monostable […]

Math of the 555 Timer

Math of the 555 Timer

If you’ve been following along with the 555 timer series, this video describes how to derive the formula that describes the timing of the circuit. Starting with just 2 components, we’ll work our way to an answer.

How to Control the Duty Cycle of a 555 Timer

How to Control the Duty Cycle of a 555 Timer

Continuing with a focus on the 555 timer, this video tutorial looks at how to vary the pulse width of a 555 timer’s output. It’s all possible with just a a hand full components. By varying the duty cycle one may vary the blink rate on an […]

Cascading 555 Timers for Custom Blinking LEDs

Cascading 555 Timers for Custom Blinking LEDs

For the past several weeks we’ve looked at blinky LEDs, 555 timers, and resistors. This week it’s time to put it all together into an application. A YouTube subscriber suggested the project as follows: How would you go about having an led blink twice, then […]