[0:00] i recently got sent one of these wii o
[0:02] terminals from seed studio it’s a nice
[0:04] little device it’s got a 2.4 inch lcd
[0:07] screen along with a five-way button on
[0:09] the top
[0:10] along the base we’ve got two grove
[0:12] connectors and there’s an sd card slot
[0:14] along with three more buttons on the top
[0:17] on the bottom there’s a 40 pin gpio
[0:19] connector that is compatible with the
[0:21] raspberry pi
[0:22] looking under the hood we’ve got a cpu
[0:25] that is different from the boards we
[0:26] normally play with the wiio terminal
[0:28] uses an atsamd51p19
[0:31] with an arm cortex m4f core this runs at
[0:34] 120 megahertz but you can boost this
[0:36] clock speed up to 200 megahertz if you
[0:38] need to
[0:40] connectivity is provided by a realtek
[0:42] rtl870
[0:44] which gives this dual band 2.4 and 5
[0:47] gigahertz wifi along with bluetooth
[0:49] there’s an inertial measurement unit so
[0:51] you’ve got a gyroscope and an
[0:52] accelerometer and it has a light sensor
[0:55] and infrared emitter
[0:57] more interesting for our projects it’s
[0:59] got a built-in microphone and a buzzer
[1:01] now the buzzer is not that useful at the
[1:02] moment and is only suitable for playing
[1:04] tones but the built-in microphone seems
[1:06] to be usable
[1:08] we’ve got a screen and a microphone so i
[1:10] thought it would be fun to port over my
[1:12] audio monitor code to it
[1:14] there’s a couple of things that need to
[1:15] be modified the first thing is there’s
[1:17] no i squared s peripheral for getting
[1:19] samples from the microphone the
[1:21] microphone is connected to an analog pin
[1:23] and we need to use analog read to get
[1:25] the current value
[1:26] i did find some examples of using dma to
[1:28] read this value but to keep the code
[1:30] simple i’m using a timer to read the
[1:32] samples i’m only going to sample the
[1:34] audio at 8khz which is good enough for a
[1:37] nice audio display and won’t tax the cpu
[1:40] too much
[1:41] so my first attempt at getting it
[1:42] working was a bit lackluster and after
[1:45] instrumenting the code with some timings
[1:46] i found this was due to the siege studio
[1:48] fork of the tft library it’s taking
[1:50] around 150 milliseconds to render the
[1:53] frequency bar chart
[1:54] weirdly when showing the spectrogram
[1:57] which is rendered at full screen is
[1:59] pretty good taking just 30 milliseconds
[2:01] to render the whole screen so this leads
[2:03] me to suspect it’s a fairly simple fix
[2:05] on their side so i imagine there will be
[2:07] an update at some point to fix this
[2:09] performance problem
[2:11] fortunately in the meantime there’s an
[2:13] alternative library that supports the
[2:14] display and can render all the screens
[2:16] in around 30 milliseconds which is more
[2:19] than fast enough for us
[2:20] the two display libraries are pretty
[2:22] much compatible in terms of method calls
[2:24] so it’s a pretty straightforward swap
[2:26] out
[2:27] what i’ve done is make a very simple
[2:29] base class for the display that defines
[2:31] the methods i need to call i’ve made all
[2:33] my code depend on this class
[2:35] and then to swap out the two different
[2:36] displays i’ve got a wrapper class that
[2:38] derives from this base class and
[2:40] delegates on to the real library
[2:43] to reduce writing lots of boilerplate
[2:45] code i’ve used a template class this
[2:47] takes advantage of the fact that both
[2:49] libraries implement pretty much the same
[2:51] methods so i just need to write the code
[2:53] once and the c plus compiler works out
[2:55] what i’m trying to do
[2:56] if you like this kind of coding then
[2:58] you’d probably enjoy the previous video
[3:00] on improving your arduino code using c
[3:02] plus
[3:03] it works pretty nicely i really like
[3:05] these devices with displays and
[3:07] microphones there’s lots of potential as
[3:09] a shame the speaker is not a bit more
[3:11] useful but there is a bolt-on module
[3:13] that will give you a proper speaker i’ve
[3:15] put the code up on github so you can
[3:16] give it a go if you want and if you’ve
[3:18] got a wii terminal let me know how it
[3:20] works i think we’ll be exploring this
[3:21] device in the future