Someone asked in the comments of a previous video, what all the outlet tester light meanings were. Tester tools typically have a limited space and only explain the most common ways plugs are miswired. In this video, Harley looks at all the different ways a plugs wiring could be messed up and shows what lights the tester shows.
Here at House of Hacks we do tutorials, project overviews, tool reviews and more related to making things around the home and shop. Generally this involves wood and metal working, electronics, photography and other similar things. If this sounds interesting to you, you may subscribe here.
Music under Creative Commons License By Attribution 4.0 by Kevin MacLeod at http://incompetech.com.
Intro/Exit: "Hot Swing"
Transcript
A number of years ago, I did a video talking about this and how to use it.
It's a 110 outlet tester and it lists 6 different ways that outlets can be miswired and gives you codes for these lights light up.
A couple people commented that they were getting the lights lighting up in ways that weren't documented.
In today's video, I'm going to go through all the different ways, there's 6 listed here but I counted 12 different ways, an outlet could actually be miswired and see what kind of light codes we get for the different ways that they're wired.
If we're just meeting, I'm Harley. Welcome to the House of Hacks.
I make things out of various things here in the workshop.
Sometimes that includes doing 110 wiring, for which these are really handy.
Let's go over to the workbench, see the test setup and then checkout the 12 different combinations and what the lights look like for those.
At the bench here, I have an outlet that's wired correctly and the wires are plugged directly into an outlet.
I do not recommend you do this at home.
There is exposed 110 voltage here.
And there's a high risk of shock, injury and potentially even death.
So, I'm doing this so you don't have to.
Right now, this is plugged in over here in the correct configuration, as we can see from the outlet tester.
I'll go through the 6 different documented ways that the tester will report errors and then I'll go through the 6 undocumented ways and we'll see what the lights look like.
So, hopefully, that will tell us something about what those commenters were asking and give you that information.
OK, here we can see we have correctly wired because our lights are lit up to be correct.
And now we have hot/neutral reversed with the red and orange.
And now we have the open hot with no lights lit whatsoever.
And here we have open neutral with a single orange light.
Here we have a hot/ground reversed configuration.
And here we have the last documented item with an open ground with just a single orange light.
Now let's take a look at what other combinations we have that aren't documented.
Here's a ground/neutral reversed. Interestingly, it doesn't show up any different than a correct.
And here we have an open hot with neutral/ground reversed.
And in this case we don't get any lights because we don't really have any power coming into the tester for it to be able to light anything up with.
OK, this is a very confused situation where we have hot going to neutral and ground and neutral swapped.
OK, here we have a situation where ground and hot are reversed and neutral is open.
Looks like the tester can't detect this situation.
Now this is a really twisted situation here again where nothing is anywhere close to being correct.
Neutral is wired to hot. Hot is wired to ground and ground is wired to neutral.
OK, and here's the last undocumented configuration where ground is open and hot and neutral are reversed.
If you're interested in the video where I talk about how to use one of those outlet testers, it's in this video over here.
Down here is a video that YouTube thinks you'll enjoy.
Want to make an Arduino project a bit more complicated than blink? In today's episode of House of Hacks, Harley starts a project on how to make a binary clock. This project will use an Arduino and be presented in multiple parts. Today, the first part will be the overall requirements and design. In future videos, the software, circuit and finishing it off with an enclosure will be covered.
Resources
All the information to make this project: https://www.house-of-hacks.com/p/arduino-project-binary-clock.html
If you just want to buy one: https://amzn.to/3eGXFVD (Amazon affiliate link)
Get a digital version of the new Arduino poster by signing up for the House of Hacks newsletter: https://list-optin.house-of-hacks.com/arduino
Or a printed copy of the poster can be bought on the House of Hacks store: http://store.house-of-hacks.com
Contents
0:00 Project introduction
0:59 Welcome and about House of Hacks
1:19 Description of BCD
2:14 BCD for binary clocks
3:05 Project requirements
4:02 Controlling the LEDs
5:45 Tracking the time
6:18 Adjusting the time
7:23 Arduino selection
About
Here at House of Hacks we do tutorials, project overviews, tool reviews and more related to making things around the home and shop. Generally this involves wood and metal working, electronics, photography and other similar things. If this sounds interesting to you, you may subscribe here.
Music under Creative Commons License By Attribution 4.0 by Kevin MacLeod at http://incompetech.com.
Intro/Exit: "Hot Swing"
Transcript
A number of years ago, at a software conference, one of the evening activities as an outing to a hands-on science museum.
While there, I noticed and picked up this binary clock.
It uses something called BCD encoding and I thought it'd be kind of cool to make my own version of this as a project.
Technically, it could be done with some simple logic circuits and a timer.
But this would involve more hardware design and wiring than I wanted to be involved with and so I'm going to go the easy route and use an Arduino.
This is going to be done in four parts.
Part one today is the basic requirements and design.
Than as I'm waiting for parts to come in, I'll go over the software design and how to actually do some testing without having a complete circuit finished.
The third video I'll assemble all the circuits and get it running.
And then the fourth video will be creating an enclosure for it.
Welcome to the House of Hacks. If we’re just meeting, I’m Harley and I make stuff out a variety of materials.
For example, in this project, we're doing design discussions, and software and electronics and mixed media for the enclosure.
If making a things out of a variety of materials in the workshop is something that's your thing, consider subscribing and you won’t miss future episodes.
BCD is an acronym for Binary Coded Decimal and this was an encoding system that IBM came up with nearly a 100 years ago in the 1920s for use in their early mechanical devices.
As early computers came on the scene, they took this basic coding that they used and expanded upon it to use in the computers.
It was called EBCDIC at the time and was actually used until relatively recently.
Interestingly, early in my career, I had to write an ASCII to EBCDIC conversion routine for use by our business partners.
Before going to the whiteboard, a couple notes.
First, the code and schematics for this project, is available for free download off of GitHub.
And second, a commercial version of this clock, kind of like the one that I picked up at the conference, as well as all the materials I'm using in the project are available on Amazon. I’ll leave links for everything down in the description below.
In BCD, each column represents a decimal digit, coded in binary. The first column is the tens digit for the hours, the second is the units column for the hours. Next, we have the tens and units digits for the minutes and the tens and units digits for the seconds.
In decimal, we need four bits to cover the all digits 0-9 in binary. So all the units columns on the LEDs have four LEDs. Because on a clock, none of the tens digits go all the way to 9, we don’t need a full 4 bits for each of the tens columns. Hours for example only go to 2, so we only need 2 bits for a 24 hour clock. The minutes and seconds only go to five so we only need three bits for those.
So, to make this, what are our requirements?
For the LEDs, we have 3 groups of 4 and 2 groups of 3 for a total of 18 and another 2 for a total of 20 LEDs that we need to control.
Second, we need a way of keeping track of the time.
Third, we need a way to set the time.
I’ll talk about all these requirements in detail but first I’m excited to announce that I’m working on some Arduino training materials. I have an Arduino reference poster available now and am working on a book for people new to digital electronics and programming the Arduino. A digital version of the poster is available by just signing up to the House of Hacks mailing list where I’ll keep you updated on things happening here. I won’t bombard your email with a bunch of stuff. Just occasional updates when products are released and an occasional news item that I think you might find interesting related to making things. If you’re interested in this, there’s a link below in the description below.
Now, back to the design...
Looking at controlling the LEDs, my first inclination was to think about this as a single string of 20 bits where each digit in each group was put inline with the rest of the bits. The common way of working with large numbers of LEDs is to use a '595 based shift register. This only requires three pins on the Arduino but provides a number of digital outputs. This is so commonly used that there’s a shiftOut command built into the Arduino ecosystem. ‘595 chips typically only work with 8 bits (although there are variants that have more bits) but they can be daisy chained together so you can have an almost arbitrary number of digital outputs, all controlled by only three pins.
Since there’s 20 bits needed and each ‘595 provides 8 bits, I thought about using three shift registers, daisy chained together. This would give 8 times 3, or 24, bits. The first 20 bits would be used and the last 4 bits would be ignored.
I coded up a prototype sketch using this idea but it ended up being more messy than I really liked. All the code was one big blob with a bunch of dependencies spread throughout the whole thing. Some of that mess could be cleaned up with some refactoring, but it was still going to be more messy than I really liked.
Upon reflection, I realized each group of two numbers only needs at most 7 bits and I have three groups. For the purposes of this project, I could still use the three ‘595s but instead of daisy chaining them together, I could connect each one to the Arduino directly. This would help make the code cleaner. Each ‘595 needs three pins, so that’d be a total of 9 pins for the LEDs instead of 3. Let’s look at the rest of the requirements and see if there are enough pins.
To track time, the most reliable would be to use a clock module. A real time clock module, also called an RTC, is designed to interface with micro controllers and has it’s own battery backup. There are a number of different models. I selected to use a DS1307 because they can be had inexpensively and communicate with the Arduino using only three pins over the I2C bus.
It would also be possible to use the Arduino itself to track the time although I’m not to sure how accurate that would be. It would provide a software only solution though.
Finally, we need a way to set the time.
The commercial unit I have uses two buttons. One increases the hour each time it’s pressed. The other increases the minute each time it’s pressed and if they’re both pressed at the same time, the seconds are increased.
This could work, but I don’t have any good buttons that’d be appropriate for mounting in an enclosure and, in my spare parts bin, I have a rotary encoder.
Rotary encoders come in different styles. This particular one allows the user to spin it in either direction without any limits. It can also be pressed to indicate an event. The micro controller can detect which direction it’s turned and take appropriate action.
I think this would be easier to make accessible to the user in the enclosure, so I’m going to use it. It uses two pins to the Arduino to communicate the rotary action and one pin to communicate being pressed.
So, all in all, I’m looking at using 9 pins for the three ‘595s, 2 pins for the clock module and 3 pins for the rotary encoder. A total of 14 pins.
Since I want to keep this pretty compact, I’m going to select the Arduino Micro. It’s only about 2 inches long and about 3/4 inch wide and designed to go in breadboards and pre-made circuit boards with standard hole spacing. And it has 18 digital I/O pins. Four more than then 14 that we need.
I think it should work well.
So, I’ll go order the parts and, while waiting for them, I'll show you the software in this video.
If that video hasn’t been released yet, I’ll see you in this other video where I do an Arduino project simulating wind to make wind chimes sound indoors.
