Skip to main content

Little things that go wrong...

Who has shorted the 5Vdc supply to GND on the Nano? 

And now it does not even show the power LED, or it is on very dim?
You simply destroyed the MBR0520 diode, labeled D1 in the "+5V Auto Selector" circuit on the board.

How to fix?

Either order another replacement MBR0520LT1G, 0.5A, 20V, Schottky  Diode, or promise yourself to never, ever short Vcc to GND again and solder a jumper in!

Diode labeled B2

Getting less expensive Arduinos from Ebay?

Well, a lot of times the USB connector is not soldered properly and you get intermittent power or data to the ATMEGA chip.

How to fix?

Touch all the pins up with a solder iron and flux.

Popular posts from this blog

Pi Pico, we smell competition in the land of the RRRduino! 

Pi Pico on an N-scale gondola Pi Pico, we smell competition in the land of the ‘duino!  Our very favorite low cost microcontroller system is seeing some fresh competition.  Everyone by now has heard about the Raspberry Pi, some fruity company in the United Kingdom, making single board computers!  They run Raspbian (or other flavors of Linux and are capable of some Windows versions) for as little money as $10 for the Pi Zero W.  The more popular Model 4, with 2 GB of RAM, retails for about $29.  Add a $5  micro SD card and you have a real computer with which you can surf the internet, write code and even program Arduinos.  It also runs our other favorite, JMRI.  Of course, plug it into a small or big screen television with an HDMI cable and you can even stream Netflix.  If you want a really cool computer built into a keyboard, also check out the brand new, Raspberry Pi 400 , you might just think you own a ZX Spectrum again. These are all “comp...
Read more

Roll-up Doors with a State Machine

Roll-up a door please!  (with a State Machine in code, part 1) MHO Junction’s Molson Brewery in a 3D Layout View ( all photos and drawings by Lloyd Henchey, Ontario, Canada) We all know we can open and close close something with an Arduino and a Servo, but what if we want to a little bit more operating fun with some lights and sounds, all after a manager gives approval to open or close the door to the beer brewery before your engine is allowed to pick up or deliver a car? Control Panel at the brewery   Six doors under construction at the Molson brewery on the MHO Junction  Engine pulls up to the red light, shift manager (operator) grants permission, door raises up with alarms and a flashing red light, door goes all the way up, light turns green , engine or car can proceed! Same flashing red light going down and maybe different door squeaking noises. All good articles start with a YouTube video: youtube.com/watch?v=-8EnpUgTqR4 ! This article will introduce you to a “Fi...
Read more

Layout sound on demand!

Here we go...all the sounds that you have collected over the years can now be heard from your railroad. In this article you will wire a sound playing module to a speaker and a Nano with 6 wires.   Imagine a button to announce the next train ready to leave, a light sensor noticing a stock car at the loading chute making some cattle noises, wheels squealing around a curve, or on my layout, elephants and lions in the wild! DFPlayer Mini pinout   So, save some sounds, (or “songs” called from here on), in MP3 format, onto a micro (u) SD card using your personal computer. Reading the documentation makes it a bit confusing, from: the order matters in which you drag the files to the uSD card, to: having 100 folders with each 255 sounds and commands calling which file in a folder?!? What I did was save my sound files as 001.mp3, 002.mp3 and so forth in the root folder of the drive, and had no trouble getting them to play. Remember to properly “Eject” the card using your operati...
Read more