Introduction: Clickety-Clackety Sunlight Wave Machine
When connected to two 12-volt photovoltaic panels wired in series, this wonderful, indispensable device, which Elap believes every home should have, counts the number of units of sunshine as the waves are created. The brighter the sun, the faster the waves move and the faster it counts. It is automatic because, when the sunshine subsides, it automatically resumes working when the light comes back.
This wonderfully useful machine comprises 15 old GPO-type relays. Fourteen of these are wired into a ring. When a relay is momentarily turned on, it locks itself on. Each of these fourteen ring relays turns on the next one (which locks on), and breaks the circuit to the previous-but-one relay so that it is turned off. When the machine is first turned on, nothing will happen because all the relays are off and there is no power to any of them. The way round this is to introduce a control relay: when this relay is off, as it will be when the machine starts, it completes the circuit to one of the ring relays, a later ring relay turning on the control relay (which locks itself on) so that it is no longer interfering with the starting ring relay. Clear as mud, huh?
As each relay is turned off, it gives an impulse to a finely-balanced rod, thus creating the wave effect. At the flick of a switch, a double wave effect can be initiated; if the sunlight reduces, the machine automatically switches to a single wave until (and if) the light is restored.
In bright sunlight in double-wave mode, there are about 75 waves per minute.
Believe it or not, it is very relaxing listening to the clickety-clacks as the sun beams down.
HOW TO MAKE THE CLICKETY-CLACKETY SUNLIGHT WAVE MACHINE
It is assumed that the reader is familiar with an electrically operated switch called a relay, and that the soldering of a wires onto terminals is something which they can do.
At least half a dozen relays will be needed, a dozen or more being ideal. They will be wired together electrically as a ring, but the physical appearance could be circular or a straight line or even random. One of the relays will be used as a control relay. To work from a single 12-volt solar panel, the relays should have a resistance of not more than 1000 ohms; relays of around 2000 ohms will need two 12-volt solar panels wired in series - some experimentation will be required to see what works in practice. Relays with different resistances can be mixed.
Each 'ring' relay will need to have at least the following types of contacts:
- A normally-open (NO) pair of contacts which will be used to hold the relay on once it has been switched on
- A NO pair of contacts which will be used to turn on the next relay in the ring
- A NO pair of contacts which will be used to make sure that the control relay is never the only one switched on
- A normally-closed (NC) pair of contacts which will be used to turn off the previous-but-one relay in the ring.
In addition, one of the ring relays will need a pair of NO contacts to provide a pulse for the counter, and another (or the same) ring relay will need a pair of NO contacts to turn on the control relay.
In the pictured Sunlight Wave Machine, the ring relays (see the 2nd photo) have 6 sets of changeover (CO) contacts.
Bracket for the Relays
The relays will need to be fixed a wooden support. In the Sunlight Wave Machine, the relays have been attached to a wooden strip, and this has been screwed to a wooden frame. There is plenty of scope for some original thinking here.
Terminals and Switches
Three pairs of terminals will be required, and two switches. The terminals are for the panel input, the counter power and the counter itself. One switch is connected to the power from the panel, and the other is for the single-wave / double-wave feature.
Up to 20 metres of thin single-core wire will be needed for a 14-relay circuit.
If lower-resistance relays (not more than 1000 ohms) are used, one 12-volt panel is all that's required. As a rough guide, one relay requires around 30 milliamps to operate, and since up to seven relays could be on simultaneously, around a fifth of an amp is needed. A 5-watt solar panel will more than suffice, but of course a larger panel will work in weaker sunlight.
If higher-resistance relays (up to 2000 ohms) are used, two panels will be required (in series - it's the extra voltage which is required, not extra current).
An Electrically-operated Counter
An electrically-operated counter will be required. The machine allows for a dedicated input (which may or may not be from the solar panel) to be connected for the counter, and so an AC or DC one could be used. It is recommended that the voltage is 24 or less, for safety reasons. Of course, the pulse could operate a solenoid which worked a mechanical counter... the possibilities are endless.
The tools required are some wire cutters/strippers, a soldering iron and a screwdriver or spanner (depending on how the relays are to be fixed), and whatever woodworking tools are required for the frame.
Also required are some screws and/or nuts, bolts and washers. Various pieces of wood will have to be acquired. The precise design of the machine can depend on the resources available! And don't forget the solder.
How to Do the Wiring
Notation (see the 3rd photo)
A1 and A2 are a pair of normally-open contacts which will be used to hold the relay on once it has been switched on
B1 and B2 are a pair of normally-open contacts which will be used to turn on the next relay in the ring
C1 and C2 are a pair of normally-closed contacts which will be used to turn off the previous-but-one relay in the ring
D1 and D2 are a pair of normally-open contacts which will be used to make sure that the control relay is never the only one switched on
T1 and T2 are the coil terminals of the relay
In these instructions, the first relay is deemed to follow the last. The italicised instructions denote the checking of connections which should already have been completed.
For the ring relays, proceed as follows:
1) Connect T1 of each relay to T1 of the next relay in the ring, and one of these to the +ve input from the panel
2) Connect T2 of each relay to B1 of the previous relay and A1 on the same relay
3) Make sure that A1 of each relay has been connected to T2 of the same relay
4) Connect A2 of each relay to B2 of the previous relay and C1 of the next-but-one relay
5) Make sure that B1 of each relay has been connected to T2 of the next relay
6) Make sure that B2 of each relay has been connected to A2 of the next relay
7) Make sure that C1 of each relay has been connected to A2 of the previous-but-one relay
8) Connect C2 of each relay to C2 of the next relay, and one of these to the -ve input from the panel
That complete the ring relays - but as it stands, no relay will switch on because all the circuits are open. This is where the control relay comes in: it will, when off, turn on relay #2 (say), and when it is turned on (by relay #5, say), and is locked on by a pair of its own contacts, it will cease to hold on relay #2 now that the relays are in action.
At this stage, prodding one of the relay's armatures should set the relays in motion - if nothing happens, check the connections.
For the control circuit (see the 4th photo), proceed as follows:
1) Connect an unused normally-open contact on ring relay # 5 to T2 of the control relay
2) Connect the other normally-open contact on ring relay #5 to A2 of the control relay
3) Connect T1 of the control relay to D1 of ring relay #6 (say)
4) Connect A1 of the control relay to T2 of the same relay
5) Connect A2 of the control relay to the -ve input from the panel
6) Connect C1 of the control relay to T2 of ring relay #2
7) Connect C2 of the control relay to the -ve input from the panel
We have to make sure that the control relay is never the only one switched on - if it was, no circuit would be complete and nothing would happen until the sunlight was so weak that the control relay finally turned off, and then the sun came out again.
1) Connect D1 of each ring relay to D1 of the next ring relay
2) Connect D2 of each ring relay to D2 of the next ring relay
3) Connect D2 of one of the ring relays to the +ve input from the panel
We now have to connect the single-wave / double-wave switch. This is easy: simply connect A1 and A2 of a ring relay with A1 and A2 of another ring relay, preferably one that is equidistant from it forwards or backwards, making sure that the single-wave / double-wave switch is in series with the connection.
We have to connect a counter. Connect a spare pair of ring relay normally-open contacts to the counter terminals, making sure that the power-source terminals are in series with the circuit.
The input from the panel(s) should be connected to the terminals via the Power On/Off switch.
How to Achieve the Wave Effect
In the first photo, it can be seen that some rods have been balanced on the relays' armatures. Some screws with washers on them have been used to make them finely balanced, only just in contact with the armatures. When a relay is switched off, the impulse from the magnetically-released armature is imparted to the rod, thus causing it to spring upwards.
A bar underneath the rods can be raised to turn of the (noisy) wave effect to that the user can relax to the clickety-clacking of the relays.
Now admit it - you really couldn't do without this machine, could you? Be honest, now.