Robots and Physical Computing

Friday, 2 March 2018

Microbit Neuron - producing a single neuron using a microbit

This post is in response to a question from Carl Simmons (@Activ8Thinking) about has anyone built a microbit simple neuron.

Quick Overview

Inputs are going to be binary
Weighted sum is bias+W1*input1+w2*input2
If weighted sum>=0 then the output is True (T on the LEDs) or '1'
If weighted sum<0 then the output is False (F on the LEDs) or '0'

First attempt - A simple gate using the buttons A and B
So first attempt uses the A and B buttons on the Microbit as the two inputs and it produces T for true and F for false on the LEDs. So the weights produce an AND if the bias is changed from -2 to -1 you get an OR.

More Physical Solution for Single Neuron

So in this case the buttons are removed and P0 and P1 formed the inputs the weights are the same as in the previous example with the bias of -2 being used to produce a AND gate. Programming-wise this is a simpler solution than the previous one, no converting button presses into inputs.

Figures below show the 'neuron' in action.

First, one shows the case when both inputs are '0' ie. not connected to 3v connection. The output is False (F on the LEDs)

This figure shows when only one input is '1', the output is False.

Finally what happens when both inputs are '1', the output goes to True (T on the LEDs).

Where next?
Adapting the code so it produces a digital output and then combining them into a small network to solve a problem that a single neuron can't do the Exclusive OR (XOR).

All opinions in this blog are the Author's and should not in any way be seen as reflecting the views of any organisation the Author has any association with. Twitter @scottturneruon

Tuesday, 27 February 2018

WebVR playtime 2: video, 360 video and objects

This is going to be a short series of articles about some experiments with WebVR Web based Virtual Reality - in this case based on the wonderful A-Frame (https://aframe.io) . In the first post WebVR playtime 1: Basics of setting up, images and rotating blocks. I looked at setting up a scene and then rotating an object.

In this post, I going to recap the basics, then look at adding video, 360 degree video, and models developed elsewhere.

1. The approach and setting up
I chose to use A-Frame (https://aframe.io) inside Thimble (https://thimble.mozilla.org ); Thimble was selected for four reasons it is an online editor, simple to use, it is free and you see the preview immediately. In Thimble though try to keep the image or video file sizes small.

You can pretty much treat it as HTML, after you have added the script file shown in bold.
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<script src="https://aframe.io/releases/0.7.0/aframe.min.js"></script>
</head>
<body>
<a-scene>

</a-scene>
</body>

</html>
The items to be add all go between <a-scene> and </a-scene>:
<a-text value="Hello" color="black" position="0 1.8 0.5" width="10"></a-text>
<a-sky color="orange" ></a-sky>
For example
<a-scene>
<a-text value="Hello" color="black" position="0 1.8 0.5" width="10"></a-text>
<a-sky color="orange" ></a-sky>
</a-scene>

The video below shows setting up and adding a box to the scene.

2. Adding video
Actual in some ways it as easy to add video as adding an image, at it's simplest adding src="" with either the URL or relative filename in the speech marks can be used for both images and video. Alternatively using <a-video src=""></a-video> combination with again the filename or URL between speech marks adds a block and pastes the video on top. The video below shows a worked example of these two approaches

3. 360 degree video.
A-Frame allows 360 degree to be incorporated into the scene using the <a-videosphere> tag. The video below shows a worked example of this. The video below shows another worked example.

4. 3D objects and Assets
We can also add 3D models that others have developed into our scene. In the video below a Penguin, defined externally using .obj for the model and .mtl for the material, is loaded into the scene.

To read more go to https://aframe.io/docs/0.7.0/introduction/

All opinions in this blog are the Author's and should not in any way be seen as reflecting the views of any organisation the Author has any association with. Twitter @scottturneruon

Sunday, 25 February 2018

WebVR playtime 1: Basics of setting up, images and rotating blocks.

This is going to be a short series of articles about some experiments with WebVR Web based Virtual Reality - in this case based on the wonderful A-Frame (https://aframe.io) . Ok, a bit of context, I have been working with some MSc students on this area and we have been exploring this area together - I love learning from and with my students.

Firstly, it is great fun and nowhere near as hard as I thought it was going to be when I first started.

1. The approach
My approach is to use A-Frame (https://aframe.io) inside Thimble (https://thimble.mozilla.org ). Thimble was selected for four reasons it is an online editor, simple to use, it is free and you see the preview immediately. Its main downside is the size of images and videos has to be relatively small and not too many of them.

2. How easy is it?
You can pretty much treat it as HTML, after you have added the script file shown in bold.
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<script src="https://aframe.io/releases/0.7.0/aframe.min.js"></script>
</head>
<body>
<a-scene>

</a-scene>
</body>

</html>
The items to be add all go between <a-scene> and </a-scene> with a parent-child relationship; for example A block of text saying Hello in black and making the sky orange are all 'children' of <a-sceme>:
<a-text value="Hello" color="black" position="0 1.8 0.5" width="10"></a-text>
<a-sky color="orange" ></a-sky>
For example
<a-scene>
<a-text value="Hello" color="black" position="0 1.8 0.5" width="10"></a-text>
<a-sky color="orange" ></a-sky>
</a-scene>

The video below shows setting up and adding a box to the scene.

This next video takes this a little further by adding rotation to an object.

In this video mapping an image to an object and changing camera position is looked at.

In later posts some further ideas will be explored.

To read more go to https://aframe.io/docs/0.7.0/introduction/

All opinions in this blog are the Author's and should not in any way be seen as reflecting the views of any organisation the Author has any association with. Twitter @scottturneruon

Monday, 25 December 2017

Gesture controlled python robot unicorn (or is it a rhino)

In the previous two post I built and played with a robot unicorn from Do it Kitshttps://doitkits.com/product/robot-unicorn/. In the first post, python was used to get it to move forward, backwards, left, right and stop. The second post discussed using a second microbit to send the movement instructions via the microbit's radio module.

This post looks at extending the idea to using the accelerometer to pick up directions and send them to the robot unicorn (that still seems weird to write). Microbit's accelerometers, using the x and y directions, provide the inputs and then send the direction commands. The robot unicorn code is the same in the second post, the new code for the gestures is shown below.

This a work in progress it detects x and y changes together so it does have a tendency to do one direction and then the other. This needs further work.

All my code for the robot unicorn projects can be found at: https://github.com/scottturneruon/Robo_unicorn_python or if you want to cite it : Turner, S., 2017. Robo_unicorn_python. Available at: <Robo_unicorn_python> https://doi.org/10.6084/m9.figshare.5729583.v7

All opinions in this blog are the Author's and should not in any way be seen as reflecting the views of any organisation the Author has any association with. Twitter @scottturneruon

Saturday, 23 December 2017

Radio controlled microbit Robot Unicorn

In a previous post a robot unicorn was built from a kit (Do it Kits https://doitkits.com/product/robot-unicorn/) and controlled to do a fixed sequence of actions. In this post a similar thing will be done, but this time the actions are not fixed within the robot itself, but in response to messages sent from another microbit via the radio module.

Sending

Sends out messages via the microbit's radio module, e.g. fwd for forward or tr for turn right; as well the name of the actions scrolls across the microbit.

On the Unicorn

Revieves messages via the microbits radio module, e.g. bwd for backward or tl for turn left; then carries out the action for 500ms. The time was selected to give the system enough time to finish the action before the next message is expected.

All the code available at Turner, S., 2017. Robo_unicorn_python. Available at: <Robo_unicorn_python> https://doi.org/10.6084/m9.figshare.5729583.v7

All opinions in this blog are the Author's and should not in any way be seen as reflecting the views of any organisation the Author has any association with. Twitter @scottturneruon

Friday, 22 December 2017

Robot Unicorn, python and a microbit

Yesterday (21/12/2017) I took delivery of a Robot Unicorn kit - now those were three words I don't think I would ever write let alone say from Do it Kits https://doitkits.com/product/robot-unicorn/ based around the microbit.

There is a fantastic video produced by Do It Kits on how to put the kit together and another on programming using Blocks:

Using the second video as a starting point I have produced my version of it in Python (see below). Essentially go forward, backwards, turn left and turn right, as well as pause.

I have probably wired it up back to front, so my settings in the code are the other way around to the ones used in the video - you may need to swap backwards and forwards around; as well as left and right.

This is a cute kit. How can anyone resist a Robot Unicorn?

All of the code available at Turner, S., 2017. Robo_unicorn_python. Available at: <Robo_unicorn_python> https://doi.org/10.6084/m9.figshare.5729583.v7

All opinions in this blog are the Author's and should not in any way be seen as reflecting the views of any organisation the Author has any association with. Twitter @scottturneruon

Sunday, 19 November 2017

Micro:bit Robot Arm

In this post, I am discussing using a recently bought CBIS BBC micro:bit RobotArm, but play with it using Python (or rather micropython).

Set Up
Not a lot to set up really. The base and the arm are separate and are attached with four screws (so you will need a screwdriver).

The most difficult bit is the wiring the arm to the circuit/breakout board on the base, but instructions are available through CBiS Resource portal http://portal.cbis.education/teacher/hardware. You will need a log-in for this. Also on that site, there is an example Microsoft Blocks code which includes some instructions on inserting the microbit as well - the micro:bit goes in buttons side facing upwards.

Code
Taking the values from the instruction sheet for setting it - the micro:bit key bit - the following pins were selected.
Base Pins 0 and 1
Shoulder Pins 8 and 12
Elbow Pins 2 and 13
Wrist Pins 14 and 15
Gripper Pins 16 and 11 - this is the only one I haven't got working yet.

So to test it out, a simple bit of code to drive each motor in both directions was produced and is shown below.

This is good fun to play with. The use of the micro:bit is a good idea because it's ease of use to plug-in and play with.

All opinions in this blog are the Author's and should not in any way be seen as reflecting the views of any organisation the Author has any association with. Twitter @scottturneruon