How fast should your buggy be?
3
Developing a control unit
It is possible to move the battery and any switches off the buggy and into a hand-held control unit that is connected to the buggy by a set of control wires. This has the advantage of making the buggy lighter (the heavy battery is now in the hand-held control unit) so it will go faster. 
It can be played with in a different way: walking or running along behind it, pressing switches to make the lights flash, the buzzer buzz, the buggy start, stop and change from moving forwards to backwards. The hand-held unit gives a feeling of remote control.
Developing a control unit is an activity for the more able children. To begin with the unit itself need be nothing more than a piece of stiff card. The battery can be attached with adhesive tape and two long wires run from the battery terminals to the motor. T hen a break can be made in the wire over the card and a simple on-off switch fitted into one of the wires. The switch can be held in place by making a tight fit hole in the card.
Some switches have a ring that can be unscrewed. You can use this to lock the switch in place. Extra wires and switches can be fitted to each of the electrical components on the buggy. The whole unit can be given a more professional look by making a card net to house the battery and support the switches in appropriate places. In a hand-held unit it might be better to have switches on the sides rather than the top of the unit.