Wednesday 25 July 2012

User testing

I spent the day with Adam today. I showed him the first three Little Boards (DIY littleBits) I'd made after breakfast and he spent most of the morning playing with them. During that time I built up another motor board - this one with the motor facing forward, like an aeroplane. After lunch we did some other stuff then he went back to the Little Boards and Duplo for another hour. And after dinner he played with them some more.


Here's the new motor board (below). This one has three LED's from an old AT keyboard. Adam loves LED's. I've also cut off the top lugs off the Duplo block so the end result has a lower profile.

New Little Board with forward facing motor and propeller, plus 3 LEDs. The propeller is a bit too stiff so I've added some tape to make the tips less dangerous.

One lesson learned from watching Adam is the USB tail cable has to be long enough to allow two boards to be mounted side by side. My first motor Board had a very short cable which I've now replaced. About 95mm of flexible cable is ideal.
By the end of the day we'd run our 9V battery flat so we switched to the more cumbersome 12V gel battery.
Here's the last thing he built before heading off to bed:
Twin motor  construction.

Adam loves LEDs so much I'm thinking of adding them to every board, even the simple switch Board. LEDs are great for trouble shooting connection problems.

All in all - a good first play.

Here's another creation from later in the day - this time with "super wings"!


Cheers, Paul

PS. The next day Adam had a friend 'round who also played with the Boards. His mother was quite worried about the potential for injury from the spinning propeller blades, so I stuck on some self-adhesive spongy foam left over from draft stopping around the doors and windows. It worked perfectly.

Monday 23 July 2012

Little Boards - my DIY littleBits

I've started building some of my own DIY littleBits.

The first three Little Boards glued on to Duplo blocks.
For those who haven't seen them littleBits are small, very simple electronic boards that you can connect together to make simple stuff. They feature:
  • small size about 2.5cm square (1 inch square)
  • each one has a single very simple function (switch, wire, power, LED, etc)
  • very easy connectors that snap together by magnets
  • low voltage (so not dangerous)
  • the electronics are exposed (cool)
  • well designed and made
  • attractive colour scheme
  • US$10-15 each or US$89 for a starter pack of 10 "Bits"

Adam's "flux capacitor" made from an old battey drill,
cpu fan and large  LEDs.
My son Adam is almost 5 years old. Over the last few months we've been playing with fans and motors and LED's. This play usually involves us spreading out a box of bits and pieces on the table and having a discussion about what we could do with them. Once we have an idea, I connect it up for him.

With littleBits he would be able to connect things up himself. That would be much cooler.

Given that we both enjoy making things, and I've got lots of junk to play with - I thought I'd make my own littleBits, which I'm calling Little Boards.

Note: this is probably not going to be cheaper than buying littleBits. And I'm a complete amateur electronics nerd so some of the stuff I talk about here is going to be just wrong. But you might find some interesting ideas to steal.


Progress so far


I've built a power board, a switch board and a motor board. And I've settled on USB connectors.


Power Board v0.1


Permalink
Little Power Board version 0.1. Outputs 5v DC. Stuck on a Duplo block.


The power board is a rough copy of the littleBits power Bit. I've built mine on VERO board - so it looks a bit ugly - but seems to work fine.


I've chosen to use USB Type A connectors as my interconnection "system". That's because I've got lots of spare USB cables I can use and they are pretty good connectors. The littleBits magnetic connectors are much better, but I can't get those, or anything like them - and can't think of an easy way to make my own.


The littleBits system is based on 5V DC with 3 wires; 0V, 5V and signal. Note - it's an analog system. The signal line is not a serial data stream, it's just a wire with anything from 0 to 5V DC. I'm copying that setup. I think that simplicity is a good thing for this project.


The first time I tried this with my son he wasn't able to un-plug the USB connector - it was held in too tightly. I managed to solve that by bending the clamping prongs at the top and bottom of the USB Type A socket out. Now they're not too tight and not too loose.


I'm using:
  • Pin 1 (red wire) = 5V
  • Pin 2 (white wire) = signal
  • Pin 3 (green wire) = not used
  • Pin 4 (black wire) = 0V

I don't plan on using the Green wire at this stage.


I'm using a USB Type 1 socket as the output for each Little Board. All but the power boards will have a USB plug cable "tail" as their input end.


The power Board is a simple 5V regulator which can take an input of 6-12volts and outputs 5V. I've got a 2.5mm DC socket feeding the power into the board so I can switch from a 9V battery, a small 12V GEL battery, a 6xAA battery holder, or a 12V solar panel.


I could also power the Little Boards via USB charger or a 4xAA battery holder without a voltage regulator.


My boards are about 30mm wide and of various lengths; 45mm to 65mm. (This width provides 10 lines of conducting track on the VERO board.)


By a happy piece of unplanned design the 30mm x 45mm Boards I've built so far have a slightly smaller footprint than a 2x8 block of Duplo. So I've glued them on to Duplo blocks to give them a larger contruction/play ecosystem/context.


I plan to always stick power Boards onto red Duplo block (although it would be better to use half hight blocks and cut/grind off the top "cups"). I'll use green Duplo blocks for "input" Boards and blue Duplo blocks for "output" Boards. Other connector Boards can go on yellow Duplo blocks.

littleBits use a different colour scheme but I prefer my R G B system.



Rocker Switch Board v0.1

Little Switch Board.

This a simple on/off rocker switch that I pulled out of a hair drier.

All it does is connect the signal line to the 5V line.


Motor Board v0.1

Little Motor Board.

This is a small motor that I pulled out of a CD/DVD player. The CD tray had three motors in it - cool!

Plus there's an LEDs on it.

They are just connected between 0V and signal lines. So for the motor to go there needs to be a switch Board before it in the string.


Play so far

We cut out circles of paper and glued them on to the end of the motor (which has a small pulley guide on the end of the shaft). Then we started the motor and used felt pens to create patterns on the spinning disk. We observed how the different colours combined when the motor was spinning. Adam drew on the disk when it was stopped then turned it on to see what would happen. (Mixing colours and changing shapes.)

One of the other CD player motors had a pulley wheel that had a larger diameter than the motor so Adam was using that as a "grinder".


Little Board ideas to build

Power sources: USB direct?, 4xAA batteries direct. 12V Gel battery connector. 12V PV panel connector. Cellphone batteries?

Input Boards: slide switch, lever switch, slide potentiometer ("dimmer"), rotary potentiometer ("dimmer"), light sensor switch (based on garden PV light), timer delay (using 555 timer with pot), momentary ON or OFF switch, magnetic reed switch, pull cord switch (source?!), On/Off/On slide switch to two outputs (from hair drier).

Output Boards: motor, motor with gears and CD/DVD tray, buzzer from old cellphone, LED (red, green, blue, orange, white). RGB LED with three inputs. 5 par bar graph, flashing LED's,

Wire/Connector Boards: USB extension cords (1m and shorter), branch boards with 2 or three outputs, logic Boards (AND, OR, NAND, NOR, NOT)

I'm going to try building one Little Board every spare night I have. I'll keep you posted on progress.

I'll add photos, circuit diagrams and parts lists tonight.

Cheers, Paul