Displaying a graph
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Displaying a graph

by jalsina on Tue May 07, 2013 2:47 pm

Greetings! I have an application that requires displaying a series of several hundred data points as a graph. The data will be acquired from sensors controlled by an Arduino. I'm thinking of using a graphic LCD display with touchscreen, and simply turning on one pixel in each column to represent each data point. The display should be at least 2.8" (7" would be better), and I need it to be reasonably straightforward to get my simple interface running (no animation, photos, video), with clear documentation & hopefully some code samples. Any advice on a good choice of hardware/software will be much appreciated. JCA
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Re: Displaying a graph

by adafruit_support_mike on Tue May 07, 2013 4:04 pm

If you want the whole graph to be visible at the same time, you probably want one of our 2.8" TFT breakouts or shields:

We have software libraries that make using the display more or less a plug and play affair, plus a graphics library that has primitives for drawing lines.

We have 7" displays (and larger) but to make them work you'd need more hardware. The displays we sell use NTSC/PAL signals, and generating one of those from an Arduino is a pretty CPU and timing intensive business. The Raspberri Pi has composite NTSC/PAL/HDMI video built in, runs Linux so you'd have a wide array of Open Source graphing and graphics software at your disposal, and has a range of GPIO pins that can probably be programmed to do anything an Arduino can do.

It's also possible to establish a serial connection between a RasPi and an Arduino so the Arduino does low-level hardware management and the RasPi does high-level data processing and display.
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