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Project Notes

#591 Tydirium Strobe Module

Packaging the ATtiny85 Lambda-class shuttle “Tydirium” navigation strobe circuit as a small board that can be added to an existing lighting setup.



In LEAP#589 I figured out the navigation strobe pattern for the Tydirium shuttle and demonstrated it with a freeform circuit.

This project describes a variation of the circuit on a small module/board that could be used to add the LED flashing pattern to existing LED wiring.


The ATtiny85 microprocessor does all the hard work, with some support circuitry:

  • zener diode provides some basic over-voltage protection.
  • a 2N7000 n-channel MOSFET for low-side LED control, instead of driving directly from the ATtiny85. This allows it to switch pulses of up to 500mA current through the LEDs.

Although the circuit is best powered with 3-5V, it can handle up to 9V without complaint. A 9V battery will incur 150mW dropped across the 100Ω resistor.



Breadboard Build

Module Design

The module is designed to be easily fitted to existing circuits.

There are three connections required:

  • positive power supply for the microcontroller. Ideally 3-5V, but can handle up to 9V.
  • negative power supply for the microcontroller.
  • the negative end of the LED(s) to be switched.

These connections can be made to either:

  • the screw terminals on the board
  • or soldered to the corresponding solder pads


For LED Power Supplies 3-9V

If the existing LED circuit is powered with between 3V and 9V, the module does not need a separate power supply. Connections

  • LED power supply positive connected to module positive (POWER+)
  • LED power supply negative connected to module negative (POWER-)
  • the negative end of the LED(s) to be switched connected to the module LED negative (LED-).


For LED Power Supplies over 9V

If the existing LED circuit is powered with over 9V, the module will need a seperate power, ideally 3-5V.

The easiest way of doing this is to add a separate battery pack for the module. This will work fine, as long as the negative connections of the two power supplies and the module all share a common connection.

For example:

  • a 12V power pack powering a LED array
  • 2 x AAA/AA (3V) batteries to power the microcontroller


Using Existing LED Wiring

For power supply voltages over 3V, LEDs will generally require current limiting resistors to prevent them from being overloaded and burning out.

Existing (non-blinking) LED wiring would have already taken this into account, and current limiting resistors only need to be considered if adding new LEDs to the circuit.


Here’s a quick test with a 3V (2xAAA) battery pack. At this voltage, an LED doesn’t really need a curret limiting resistor, so in this example, an LED is just directly connected between POWER+ and the LED- control terminal.



The ATtiny85 is programmed with the TydiriumStrobe.ino sketch.

Credits and References

Project Source on GitHub Project Gallery Return to the LEAP Catalog

This page is a web-friendly rendering of my project notes shared in the LEAP GitHub repository.

LEAP is just my personal collection of projects. Two main themes have emerged in recent years, sometimes combined:

  • electronics - usually involving an Arduino or other microprocessor in one way or another. Some are full-blown projects, while many are trivial breadboard experiments, intended to learn and explore something interesting
  • scale modelling - I caught the bug after deciding to build a Harrier during covid to demonstrate an electronic jet engine simulation. Let the fun begin..
To be honest, I haven't quite figured out if these two interests belong in the same GitHub repo or not. But for now - they are all here!

Projects are often inspired by things found wild on the net, or ideas from the many great electronics and scale modelling podcasts and YouTube channels. Feel free to borrow liberally, and if you spot any issues do let me know (or send a PR!). See the individual projects for credits where due.