The classroom projector: a complete value study

Film two: naming and classifying functions. Step two point one is to name every function. The purpose: the whole team agrees what every part is for, in words that don't depend on today's design.

There are four rules. Use an active verb and a measurable noun: generate light, in lumens; remove heat, in watts. Say what it does, not how it does it. Avoid weak verbs, such as provide, allow and ensure. And name the job, not the part: trap dust, not filter.

Here are some weak names, and better ones. Provide light tells you nothing you can measure; generate light can be measured in lumens. Protect user is a wish. Interrupt power is a job a switch really does, and you can test it.

Your turn. The fold mirror bends the light through ninety degrees. What is its function? Pause the film and try.

Redirect light. Not reflect light: reflecting is only how a mirror does it. A prism could redirect light too. A good function stays true even if the part is replaced by something completely different.

Now every part, group by group. The light source. The burner generates light, the reflector collects it, and the cage positions the lamp. The safety glass contains fragments if the lamp bursts. The door exposes the lamp, and the baffle deflects heat.

The optics. The fly's-eye arrays divide and distribute the light. The converter polarises it. Dichroic mirrors separate wavelengths into red, green and blue. The LCD panels modulate light, the X-cube combines the three images, and the lens magnifies the image.

Cooling and power. Three fans move air, the filter traps dust, and thermistors sense temperature. The power supply converts voltage. The ballast ignites the arc, then regulates power to the lamp.

Electronics and housing. The main board processes the signal, and the rear connectors receive it. The buttons accept commands. The case encloses components, the shutter interrupts the image, and thirty-eight screws fasten components.

Part functions are detailed. When we draw the product's diagram, related ones roll up. The two fly's-eye arrays and the superposition lens divide, distribute and superimpose light. Together they homogenise light: an even patch of light on every panel.

Step two point two is to classify them. The purpose: to separate the job the customer pays for from everything else. The basic function is the reason the product exists: project image. Secondary functions are needed for the way it's designed. Unwanted functions are side effects nobody asked for. And esteem functions make people want it, rather than making it work.

Unwanted functions need special attention. Nobody asked for heat, ultraviolet, interference, fan noise or a four hundred pound electricity bill. They're worth nothing to the school, yet each one costs money to deal with, as we'll see.

So: name every function as an active verb and a measurable noun, and say what it does, not how. Then classify it. In film three, we arrange them into a FAST diagram.

Film three: step two point three, the FAST diagram. Its purpose is to turn a list of functions into logic, and to test whether the team really understands the product.

Start with the basic function, the one the customer pays for. For the projector, that's project image.

Ask why we project an image. To communicate information. That's the higher-order function: why the customer wants the product at all. It sits on the left, outside the scope line, because this study won't change it.

Now ask how. How do we project an image? By magnifying it. How do we magnify it? First we need one full-colour image, so we combine images. And how do we get those images? By modulating light, pixel by pixel, in three LCD panels.

How do we modulate light? An LCD panel only works with polarised light, so we polarise it. And before that, we generate light.

How do we generate light? We regulate power to the lamp. How? By converting voltage. And for that, we receive power. The building's supply is outside the study, so it sits past the right-hand scope line. Everything between the scope lines is the critical path.

Now test it backwards, asking why. Why receive power? To convert voltage. Why regulate power? To generate light. Why combine images? To magnify one image. Why magnify it? To project it. If every step makes sense both ways, the logic holds. If not, a card is in the wrong place.

Some functions need more than one answer to how. To modulate light, the panels also need the light split into red, green and blue, and spread evenly. So we separate wavelengths, and homogenise light. Stacked like this, they read as AND: all three are needed. Focus image is a second answer to how we project it.

Below the path go functions that happen at the same time. When we modulate light, we process the signal, and for that we must receive it. When we generate light, the ballast first ignites the arc, with a pulse of about three and a half thousand volts.

Now the unwanted functions, in red. Generating light also generates heat and ultraviolet. Processing the signal generates interference. And receiving power means consuming energy: about four hundred pounds of electricity over five years.

Each unwanted function drags in more. Heat must be removed, so we add fans. The fans pull in dust, so we trap dust, and they generate noise. The ultraviolet must be blocked, and the interference suppressed. None of this is what the school pays for. It exists only because of something unwanted.

Above the path go functions needed all the time, whatever the projector is doing: enclose and locate components, support weight, fasten components, and contain fragments if the lamp ever bursts. Enhance appearance is an esteem function.

Next, user functions, such as accept commands and interrupt image. Then one-time functions, which happen once or only now and then: adjust angle, convey instructions, absorb shock in transit, and expose lamp when it's changed, with interrupt power at the same moment, for safety.

Last, the design criteria. Brightness, resolution, lamp life, noise, safety and price aren't functions. They're requirements that every idea must still meet. Beside them sits the objective: at least ten per cent off the landed cost.

So: start with the basic function and ask how, to build the critical path. Test it with why. Add the scope lines, the AND functions, and the when functions. And mark the unwanted ones, because they drag in cost. In film four, we put a price on every box.

Film four: steps two point four and two point five. Costing the functions, and finding where the cost sits.

Why cost functions, when we already know what the parts cost? Because a part can do several jobs, and a job can need several parts. A parts list can never show what a job really costs.

So each part's cost is shared out among its functions, based on what's inside it. The main board's video chip, drivers and memory process the signal: thirteen pounds. Its network chip receives the signal, and its amplifier drives the speaker. The ballast ignites the arc and regulates power. The power supply's filter suppresses interference. The shares always add back to the part's cost.

Do that for every part and you get the function cost matrix: fifty parts against thirty-two functions. Each row adds up to its part. Each column gives a function's cost. And the grand total must still be a hundred and five pounds twenty, or something's been lost.

Now put those costs on the FAST diagram. The colours show value, which we'll come to in film five. For now, just look at where the money sits.

Group the costs by where they sit. Fifty-seven per cent of the parts cost is on the critical path, doing the job the school pays for. The other forty-three per cent supports it, protects it, or cleans up after something unwanted.

Follow the red boxes. Removing heat, trapping dust, blocking ultraviolet and suppressing interference cost five pounds eighty-nine a projector. That's money spent only because of unwanted functions. Make less heat, or stop the interference at its source, and some of it disappears.

So, of a hundred and five pounds twenty: fifty-nine pounds fifty-four does the job itself. Thirty-nine seventy-seven supports it. And five eighty-nine exists only because of unwanted functions. That last pile is often the easiest money in the whole study.

Step two point five: rank the functions by cost, largest first, and add a running total. This is a Pareto chart. Its purpose is to show where effort will pay back. Thirty per cent of the functions, ten out of thirty-two, carry seventy-eight per cent of the cost.

These ten are where to look first: modulate light, process signal, generate light, magnify image, combine images, convert voltage, receive signal, remove heat, regulate power and enclose components. The other twenty-two share just twenty-three pounds between them.

So: share each part's cost among its functions, check it adds up, put the costs on the FAST diagram, and rank them. Cost tells us where the money goes. It doesn't tell us whether it's good value. That's worth, in film five.

Film five: steps two point six and two point seven. Setting the worth, and picking the targets.

Worth is the lowest cost shown to perform the function reliably. Cost is what you pay. Worth is what you should pay. The difference is the prize. And every worth needs evidence: it's never a guess.

There are five common ways to set it. A cheaper way that does the same job to the same standard. A supplier quote, or a should-cost. A benchmark, but only one that meets every must-be need. What the customer actually needs: one VGA input, not three. And the theoretical minimum. An unwanted function is worth nothing at all.

Be careful with benchmarks. A single-chip DLP projector is cheaper, but it gives about fourteen hundred colour lumens, not thirty-six hundred. It fails a must-be need, so it can't set the worth of modulating light.

Cost and worth give two numbers. The value gap, cost minus worth, is the money at stake. The value index, cost divided by worth, shows how far off fair value it is. One point two five or more is worth a look; two or more is a strong target. Use both: a high index on a few pence matters less than a modest one on many pounds.

Here's why it matters. Modulating light is the biggest cost in the projector, but it's good value: an index of one point oh four. Receiving the signal costs five pounds, for a job worth one pound thirty. Its index is three point eight five: ports and a cable that few schools ever use.

Sort by value gap and two functions stand out. Process signal has the biggest gap, four pounds twenty-five. Receive signal is next, at three pounds seventy, with the worst index. Locate components has an index of two: a steel cage doing a job the case could do.

Worth asks: what's the cheapest way to do this? The team also asks: how much does the school care? In a paired comparison, they take the ten functions a school would notice and compare every pair. Which matters more to a teacher: generating light, or receiving the signal? The winner scores one, two or three points. It's the team's judgement, from the school interviews, and it isn't perfectly consistent. That's normal.

Then set each function's share of the importance against its share of the cost. Process signal takes seventeen per cent of the cost for five per cent of the importance. Combine images and enclose components are flagged too. But combine images has no cheaper way to do it, so it stays. Use the graph to find questions. Use worth to answer them.

Step two point seven: pick the targets. Read the costed FAST diagram for clues, and turn each one into a question. Does the school need all of receive signal? Can fewer parts process the signal? Can we make less heat? Can we stop the interference at its source? Can two functions share one board?

These are the targets: functions with a big gap, a high index, or a cost driven by something unwanted. Not simply the most expensive ones. Modulate light, the biggest cost of all, is left alone, apart from a cheaper material in one corner.

For every target, the creative session asks one question. How else could we perform this function, at the lowest total cost, with no loss of performance, quality, reliability or safety?

That's function analysis: name, classify, build the FAST diagram, cost it, rank it, set the worth, and pick the targets. In this study, those targets led to twenty-four ideas, and seventeen per cent off the landed cost. Next, the creative phase.