AC Voltage and current continually alternate, as the name suggests, if we draw a picture of the voltage and current waveform over time, it will look something like the image below (depending on what’s using power – the current waveform – blue in the diagram below – is what you get if you look at a typical laptop power supply. There’s an incandescent light bulb in there as well).
The image was made by sampling the mains voltage and current at high frequency, which is exactly what we do on the emontx or Arduino. We make between 50 and a 100 measurements every 20 milliseconds. (100 if sampling only current, and 50, if sampling voltage and current – we’re limited by the Arduino analog read command and calculation speed).
AC Power Theory – Arduino maths – [Link]
Steve made this 6 volt 5 watt solar charge controller project, that is available at Github:
Here is a 6 volt 5 watt solar charge controller project using a dedicated printed circuit board from dirtypcbs.com and an Arduino pro-mini.
The board uses sot-23 low RDSon P channel mosfets (Si2369). It has voltage and current sensing, and 3 configurable switched or unswitched outputs.
Additionally, using a Bus Pirate you can grab charge controller voltages, currents, and other variables at 5 times a second using a Python3/tkinter program I wrote to go with this project. This program uses uses I2C to connect to the Arduino.
6 Volt 5 Watt solar charge controller – [Link]
by RFduino @ instructables.com
The RFduino compass is a fully functional stand-alone compass which also transmits the current heading via Bluetooth low energy technology to phones, tablets, personal computers or any other equipped device. The RFduino compass is known as a Bluetooth Smart device.
RFduino Compass – [Link]
by João Vilaça @ vilaca.eu:
If you love classic games like Tetris (source code) and Breakout you can now build an Arduino console to play games on the go and in color. Youtube gameplay demo.
As most inexpensive LCDs work at 3.3v the Arduino for this project works at 3.3v too.
At only 8MHz the Arduino Pro Mini 3.3v is slow by today’s standards but fast enough for most classic games.
Other Arduinos or compatibles can be used in its place. If an 5v Arduino like the Uno is used you must use a Level shifter from 5v to 3.3v or you’ll risk frying the TFT.
Build an inexpensive handheld Arduino color console – [Link]
by Dimitris Platis @ instructables.com:
During presentations, I avoid being stationary and generally like to walk around in order to increase the interaction between me and the audience. However, I am constantly being faced with the burden of having to go back to the laptop, in order to change a slide or tell a person sitting by the laptop to do that. Not cool!
This problem is usually solved by devices, called remote clickers or wireless presenters, which consist of a handheld controller with buttons that sends signals to a USB dongle plugged in the computer. After looking around to buy one, I could not find any decent option costing less than 10$. So why not make one?
Simple, easy and cheap wireless presenter – [Link]
An Arduino camera pan device project from Bajdi Electronics:
I own one of these small action cameras (SJcam SJ4000). I bought it because it’s small, and easy to take with you wherever you go. To make nice stable videos I mount it on a mini tripod. This got me thinking that it would be fun to have a little motor between the tripod and the camera to slowly pan the camera. That way I can make nice time lapse videos.
I happened to have a couple of 24byj48 stepper motors laying around, these little steppers motors have a gearbox and are 4096 steps for one rotation. They are pretty slow, so it’s ideal for this application. These motors are sold with a driver board that is basically an ULN2003 break out board.
Arduino time lapse – camera pan device – [Link]
by indigod0g @ instructables.com:
In this project, we will be making a mini weather station that measures temperature and humidity and transmits them wirelessly to a ground station, which displays the readings on an LCD display!
It’s a fairly easy project and can be used either on its own or part of something bigger.
Mini weather station – [Link]
Anyone awake in the early 2000’s knows the familiar shape of those candy bar style mobile phones. In the Shenzhen phone markets we see tons of them. Literally, there are tons of these phone passing through the markets every day. Some are resold while others are disassembled for parts and recycled. This is where all those cheap Nokia 3310/5110 LCD shields come from. It’s great to see so much reuse and recycling.
Having all these cheap LCDs is nice, but most of the interesting and useful parts are wasted. We saw a fantastic opportunity to save a heap of phones from the recycling bin and save people a pocket full of money. We can make a positive impact on the environment if we reuse some of these phones that we are literally tripping over in the streets. Let’s make an Arduino to GSM network bridge for just a few dollars.
Nokia phone Arduino shield – [Link]
by samuel123abc @ instructables.com:
Okay, here’s the deal. There are some tutorials on youtube showing how to get graphics to show on the nokia 5110 and that’s great. If you just want a simple way to do that, go and watch them instead but there are a few problems I see,
1. There are none for mac. I am using a mac and everyone in the videos are using a windows.
2. Sometimes I just wanna go to the computer and search up how to make some graphics. When searching “Nokia 5110 graphics” on google, I found nothing but some libraries and some text.
In this tutorial I will show you how to connect the display, use the code and use some web-based and downloaded tools to create some awesome graphics YOU can customize however you want. Now, enough of me speaking, let’s just begin.
Nokia 5110 graphics tutorial – [Link]
Initial testing. Ignore the humidity sensor, that was for something else.
The vacuum gauge outputs 0-10VDC. This had to be changed to a 0-5VDC range using a potential divider so it was compatible with the Arduino. Initial build used a 10k pot in place of a vacuum gauge to make it simpler.
Arduino Vacuum Gauge Display – [Link]