In this article I describe how to wire a 20x4 character display to an Arduino. I'm assuming you are using a regular 5V 8bit Arduino, if this is not the case this article will not work for you as you'll need voltage level converters. Most character based LCD displays use the same wiring, but I can't guarantee that all will be the...
Here we discuss a game library that provides an easy way to write games with 20x4 parallel display and a few micro-switches. There is quite a lot of stuff going on in this library, so I'd like to start slow and build up. First, let's start by taking a look at the parts needed to use this library: 20x4 display (other...
In this article we'll discuss building a low power Arduino menu using tcMenu library. We will use a TFT screen and a rotary encoder connected to a PCF8574 device. The device will be SAMD MKR board. I've picked this choice purposely, because it's non-trivial, and requires a lot of digging to make sure power usage is a low as possible. Running...
When we press a button that's connected to an Arduino input, it is likely that the button will momentarily "flicker" between the on and off state. This gives false readings for a short period of time after the button is pressed. Problems caused by this can range from the mild annoyance of a slight flicker, to doing something more than once...
If you're anything like me, you'll probably want to develop any large Java application using a fully fledged IDE such as IntelliJ or Eclipse. However, these are probably better run on another computer if available, transferring the code onto the PI. This article shows how to use maven to do fast turn around development onto a PI from a laptop....
If you've got a 7 segment display but are not sure if it is common anode or common cathode, then you need to check the polarity of the display. This is easily done with a low voltage supply (9V or less) from a battery, bench PSU or Arduino board. Firstly and before anything else, connect a 1K resistor between the common...
On the previous page covering single digit displays , we dealt with driving one 7-segment digit. On this page we'll use a multi-digit display and assume 4 digits. Just like single devices, multi-digit 7-segment displays have connections for A-G, DP and common, but they have a common pin for each digit, with one set of A-G and DP pins that are shared....
Measuring voltage from an analog input. Following on from the previous example ( example for driving 7 segment LED displays ). we now build on the same circuit to make a simple voltage meter. Additional requirements: Potentiometer of at least 10Kohms . In order to measure voltage, we need to use an Arduino board analog input. Usually these are marked...
There are some occasions when the amount you safely draw (assume 20mA) from an Arduino board pin is just not enough (and some Arduino boards have even lower current capability). In these cases the output needs to be buffered in order to provide more power. At this point there are several possibilities, including ready made buffer chips such as the ULN2003A....
I've got a side project of building a digitally Arduino controlled PSU that also includes an accurate component tester. In order to do this I'll have to be able to monitor the current flowing through a circuit, so I'd need some way of monitoring this. Before continuing, I'd like to say that is not an exemplar of how to build a...