micro:pegs

What do micro:pegs do?

In schools, two of the most commonly used small board computers are the Crumble and the micro:bit. In common with many other makes of expansion board, they incorporate 4 mm holes which serve as terminals for connecting external components. 

To simplify the connection of wires to the terminals I have invented a simple little device named the micro:peg. 

The LED in the picture on the right is connected to Pin 0 and GND using micro:pegs.

How do micro:pegs work?

About a centimetre of insulation is stripped from the end of the wire to be connected. The bare end of the wire is pushed down though the 4 mm terminal hole and folded back on itself. A micro:peg is then pushed into the hole to hold the wire firmly in place. Multi-strand wire works best, but single strand wire and the 'legs' of bare components can also be connected using micro:pegs (see below).

Removing the micro:peg releases the wire. The micro:peg is simply popped out by pushing on them from the back of the circuit board.

Because the connections made with micro:pegs are generally more secure than crocodile clips, the teacher can make up the circuits before the lesson and hand them out for the learners to use.

If the learners start to make a circuit but do not finish in time, their circuits can be collected in and handed back to be completed during a later lesson.

What problems are micro:pegs designed to eliminate?

A standard method of connecting components is to use croc to croc leads. These work well but when using them in my lessons I have experienced the following issues:

1. If not connected at right angles to the board clips slide along the edge strip causing short circuits or they slip off the edge strip completely.

2. Learners can find it difficult to open the clips far enough to connect them at right angles to the board as recommended. 

3. Additional connections between the component and croc clip can result in short circuits and connection failure.

4. The extra connections add to the lengths of wiring which make the circuit more difficult to understand and follow. 

5. On occasions several components need to share a common GND terminal This can be difficult to do using crocodile clips and all of the additional wiring can become quite confusing.

6. The tiny amount of plastic required to print large numbers of micro:pegs is negligible where as properly insulated crocodile to crocodile clips are relatively expensive by comparison.

The picture above shows a number of components connected to a micro:bit. It is quite common for more than one component to have to share a pin on the edge strip. This can easily be achieved using micro:bits. In the picture above you will see three components sharing the same GND terminal.

How easy are they to use?

I have used micro:pegs extensively with learners from National Curriculum Years 4 to 6 (8 to 11 years old). With a little bit of practice they found it much easier to attach and detach wires from the 4 mm terminals using the pegs than they did using crocodile clips.

Some of the advantages to be gained from using the pegs are as follows:

1. The connections are secure and do not come undone accidentally or slide along the edge strip.

2. The peg connections do not cause short circuits.

3. The simplified wiring is easier to follow and understand.

4. It is possible to match the colour of the peg to the colour of the wire from the component so learners can build their circuits by following a simple picture.

5. 'Bare' components such as an LED and wired components can be connected directly to the micro:bit's terminals.

6. Once made, the circuit is much neater.

7. Up to three wires can be connected to the same terminal.

Compare the two burglar alarm circuits below. They are built from exactly the same components and yet the one on the left using micro:pegs is much easier to build and to follow because no additional wires have been added. The four additional croc to croc clip leads makes the circuit on the right confusing and much more difficult to follow.

Manufacture and distribution

I have not sought to patent my simple invention. I am offering the micro:peg idea to commercial companies to make use of as they wish. My interest is to see the gadget used in schools to make the teaching of physical computing easier, particularly for learners in primary schools.

Should a company wish to mass produce micro:pegs for large scale distribution then all I ask in return is that the invention is attributed to myself, Graham Hastings.