• Idea to Completion

    Ben07/18/2019 at 20:52 0 comments

    My 5 year old son loves Minecraft and was also recently introduced to MagiQuest.  One issue with MagiQuest is that to play with the wand you need to be at a MagiQuest location.  I wanted to make something that would activate from the wand that he could take with him -- a small Minecraft chest seemed like the perfect option.

    I started by researching libraries available that could interpret MagiQuest wand signals.  I decided not to take the additional steps to identify specific wands as the signal seems to be inconsistent for some wands.  It does only activate when a MagiQuest signal is found and ignores other IR signals such as tv remotes.

    The common libraries for DFPlayer, IR, and Servo all use the default timers for Arduino and are not compatible without reworking them.  I did not want to go down that path as I'm not as familiar with working with timers and felt it would cause the project to get shelved.  I chose instead to split out each operation into its own ATTINY-driven module.  

    Communication between ATTINY chips is done via a single pull-up running from a master to the two slaves.  The master is also in control of identifying the MagiQuest signal and turning on the LED.

    I decided to use wire-wrap as a way to mitigate risk of mis-wiring as this board is significantly more complicated than any other project I've worked on to date.  I used a simple wire-wrap pen and 30AWG wire.  This too save the project from being shelved a few times.

    When building the project I found that switching to the buck converter caused the MP3 player to stop working.  When powered on it caused feedback into the speaker and the power indicator would blink.  I thought that I had a ground fault but I couldn't find one in testing.  The solution was to add the 1000uF capacitor to the power supply.

    The box is built from a single piece of common wood; approximately 3.5in by 16in and 1/4in thick.  I had to carve a recess into the lid to get the IR sensor closer to the opening and increase the sensor range.  My wife painted the box and I added reflective paper to the inside to increase the effectiveness of the LED.  The gems are acrylic.