Category Archives: Microcontrollers

Hexbright Hacking

The Hexbright is an Arduino-compatible open source flashlight that was the subject of a very successful kickstarter campaign in 2011.

Today I spent a short time working on some custom firmware for it.

My firmware adds two new features:

  • Button presses cycle between modes (low, med, high brightness) as usual, but if you wait longer than CYCLE_DELAY (default 5 seconds) between presses, the next press turns the hexbright off.
  • If the hexbright is left on for longer than AUTO_OFF_MINUTES (defaults to an hour), the hexbright turns off.  Handy for when you prop the light somewhere and forget about it.

You can download my custom Hexbright Arduino sketch here.  If you’re new to the Hexbright, read these well-written instructions first.  You’ll need to install the required USB driver and Arduino board configuration file.

Amazon link: HexBright FLEX, 500 Lumen Programmable LED Flashlight

Alternative software for the HV Rescue Shield

Dennis writes…

I thought I’d share with other users of the HV Rescue shield an enhanced Arduino script I have written, based on Jeff’s original software v212.

The new software retains the look and feel of the original, it can still be run in interactive and non interactive mode and starts by requesting the AVR family as before. The existing fuse settings are then printed along with the device signature and lock bits. After this the user is presented with a menu of functions.

The E command allows the user to erase the AVR.

The F command allows the fuses to be set as before. OK or fail will be printed depending on the success of the operation.

The R command allows a block of the flash memory to be dumped to screen. The user has to input the required start address in hex.

The P command is similar to the R command but operates on the EEPROM

The W command performs a simple test of the flash by writing a small block of data to it and checking it programs correctly. The user has to input the required start address in hex, which must be the first byte of a page (see device datasheet for details about page size). The user can view the test pattern written by using the R command to read it back.

The T command performs a similar test on the EEPROM but with a different shorter 4 byte pattern as EEPROM page sizes are smaller.

Dennis posted a link to his alternative software in the HV Rescue Shield support forum.

Thanks, Dennis!

Geiger Counter Kits are (finally) in stock!

Geiger Counter Kit

Geiger Counter kits are now in stock!  You can order one below or go visit the Geiger Counter kit page to learn more.

There are currently three ordering options:

  • You can buy the complete Geiger Counter kit with a tested, known good SBM-20 Geiger-Muller tube included (recommended).
  • You can buy the same kit with all parts except the Geiger tube (in case you already have one).
  • Or, you can purchase a bare PCB only (for experimenters).

You can select one of these options below:


Geiger Kit Options




Shipping is via USPS Priority Mail.  Allow 1-2 weeks for order processing and delivery.