Difference between revisions of "Think Logically"
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== Don't Over-engineer! ==
== Don't Over-engineer! ==
Revision as of 07:22, 12 September 2016
When something doesn't work right, the temptation is often to "try this," and then "try that," or "maybe I'll connect this the other way and see if that works...." This is the trial-and-error, shotgun approach and rarely is it very successful or quick. At a minimum it will raise your level of frustration. Worse yet, it may cause further physical damage to the equipment and make the issue even harder to solve. Troubleshooting blinky-flashy electronics is much easier if you follow a logical set of questions -- steps if you will -- before you jump in and start dismantling your hairline at the same time you're dismantling your equipment. If you're getting started in this hobby, here are some ideas to get you going...
Ask the right questions; provide information
- "Why don't my lights work?" is often the first complaint from beginners but it's a pretty open-ended, vague question that only beckons more questions. What do you mean by "don't work?" Do they come on at all? Do they come on but they don't dim like you want them to? Do they come on but not with the right channel control command? Do they come on and stay on and don't turn off? Do they not come on at all, ever? Do they come on but then gradually just go out on their own? Do they come on and 'kind of' work but then they don't turn all the way off? Are you using incandescent lights or LED lights? Are you using strings of A/C lights or strings of DC LEDs, or are you using 'dumb RGB' lights or 'smart RGB' pixels? So let's begin by reframing the question into one that helps bring the issue into a different focus. Instead of "why don't my lights work?" ask something like this: "What would cause all the strings of lights to come on immediately when I power up my Renard SS24 controller?" Or instead of saying "What's wrong with my controller?" ask something like, "I have a Renard-Plus TR16 and why would one of the channels stay lit all the time while all the other channels work perfectly?"
- "When I do this, that happens" is a good start to diagnosing a problem. For example, "When I plug the controller into power, I hear a little 'pop' and the fuse blows immediately and nothing works after that." If you're like me, you'll replace the fuse and try it again, probably blowing another fuse. But trying it a third time to see if the problem goes away by itself is just dumb. So think to yourself, "What is the fuse for and what part of the circuit is it in?" Then unplug the controller from power for safety, turn it over and follow the circuit traces from the power connector to the fuse, then from the fuse to the next place, and so forth. Also follow the OTHER set of circuit traces from the other side of the power connector to the next place, to the next, and so on. What you're looking for in this example is something that's causing a short circuit, which then trips the fuse to prevent more damage. Chances are you'll find there's a wire that's come loose somewhere or you might even see a darkened/sooty area on the board where the short circuit occurred. But the concept to learn here is that electricity flows on a pathway on the circuit board. It goes from point A to point B, to point C, etc. With electricity, there is always a "source" and a "return" because without one or the other, electricity can't flow from place to place. This concept applies not only to A/C power from your wall outlet but to all the DC circuitry that's on the controller's circuit board, too. And by the way, the concept applies ANYWHERE electricity is used. So in electronics, the adage isn't "follow the money," it's "follow the electricity -- the electrical path."
Understand the flow of data/electricity
- Remember the old song, "The head bone's connected to the neck bone, and the neck bone's connected to the shoulder bone, and the shoulder bone's connected to the..." etc.? With this hobby, that's a pretty good way to think of how things work when you're trying to diagnose a connectivity problem. And that's all they are, electrical connectivity problems. The data flow starts at the computer, and data is essentially a series of electrical pulses that are in a specifically organized order. So here's what happens to turn on a light:
- The sequencing software reads the com port settings and sets the computer to them
- The sequence runs, sending data out the port to the "dongle"
- The "dongle" (if it's a USB dongle) gets the data and transfers it to the wire through a connector as an electrical pulse
- The pulse goes through the wire to another connector at the other end then to the controller's circuitry
- The controller's circuitry decodes the pulse and sends the pulse to the controller's PIC
- The PIC analyzes the pulse and creates its own electrical pulse(s) to send to the PIC's proper output pin
- The pulses go from the PIC's output pin to the circuit board trace
- The pulses go through the trace and arrive at the optocoupler's input pin (such as the MOC3023 optocoupler)
- The optocoupler's internal LED lights up which then lets a small electrical current flow between its mains A/C power pins
- The A/C electricity flows through a protective resistor to the triac's "gate" pin
- The triac's gate turns on which then allows current to flow between its two outside power pins to an output terminal block.
- The terminal block allows the electricity to flow to the wires that lead to the power plug on the light string
- The electricity flows through the plug to the plug's internal fuse
- The fuse lets the electricity flow to the light string
- The lights turn on
- The point of all the above is to demonstrate that there are quite a few places along the way where things can go wrong and prevent the lights from turning on. When a light doesn't come on, following the electricity from one place to another as it flows through the various connection points allows you to isolate where the electricity stops flowing. When you find that place, usually by using some sort of testing tool like a meter, you know what to fix. Sometimes you'll find that a simple connector is the problem -- perhaps one of the wires in an RJ45 plug isn't connected to the plug's pin; other times you may find that there's a break somewhere in the wire between the two ends, or you might find that a fuse in the string's plug has blown, etc. Following the path of the electricity in a logical order is the secret to finding the problem.
- Things get a little murky, however, when you find the data is arriving at the PIC but the PIC isn't sending pulses out its pin to the MOC3023 optocoupler. You can't see inside that PIC chip to know what's going on. But in that case, at least you know that the PIC isn't working which usually means that the PIC either doesn't have any firmware stored on it or the firmware settings are wrong, but at least you've isolated the problem to that specific part. Fixing that part isn't guaranteed to fix the entire problem because sometimes there's more than one thing that's wrong. But at least it will let the electricity flow to the next logical place, and you keep checking each next place until the problem is solved.
- This diagnostic method works every time, which is a lot more predictable and efficient than the trial-and-error "try this, try that..." method.
Obvious Questions to Ask
It probably sounds a little crazy, but here's a brief list of really obvious things to ask yourself when the lights won't work. It's amazing how often the problem is solved by one of these 'reminders.'
- Is the unit/lights/etc. plugged into power?
- Is the power turned on?
- If it has a fuse, is it blown?
- Has a circuit breaker or GFCI tripped?
- Is the communication line plugged into the unit and into the source?
- Is the cable good, i.e. has it been tested?
- Is the sequence software running a sequence in a loop so you can test it? If not, the computer may be idle and not sending data.
- Does the controller's firmware have the proper channel address?
- Does the sequence have channel commands for those channels or is that channel blank?
- Are the channels enabled in the sequence for that device?
- Is the communication speeds the same for both the receiving devices and the sequence software?
- Do the lights work -- have they actually been tested?
- Did the lights ever work? If yes, what has changed since then?
- Is the computer's firewall actively blocking any programs? Or it could be anti-virus software, etc.
- Are there any messages on the computer screen that indicate a problem?
- Has the computer recently been updated? If so, perhaps the update changed the way the computer works.
- There is a very large tendency for people in this hobby to over-think or over-engineer a project, especially when it comes to "wanting it to be perfect." People fall into this over-engineering trap during sequencing when they want a certain light to come on at exactly a certain time, not 50 milliseconds early and not 50 milliseconds late... and they spend hours on the sequence to get it "exactly" right.
- The truth of the matter is that your viewers won't notice whether it's exactly right or not -- the moments are transitory and five seconds later they won't remember that one of the lights or strings was 1/20th of a second off of perfect. Does really accurate, perfect timing in the sequence make a difference? It can. But what does really accurate or perfect mean? You have to balance these against the concept of good enough or you'll find that sequencing a song might take 10 times longer than it should.
- Likewise, whether you use a white zip tie or a black zip tie to affix a light to a prop -- it doesn't matter! At night when your show is running, the lights will be so much brighter than any background they won't even see it. Whether you use sheetrock screws or wood screws to assemble wooden displays won't matter; whether you use white PVC or gray PVC won't matter; whether you use simple box corners or mitred corners won't matter because none of that will be visible.
- Certainly, you'll take pride in your craftsmanship and such issues may matter to you, but you'll find that many times, this extra effort just takes more time, often will put you behind schedule and won't make any difference to your viewers -- the show will look the same. We're not saying you should be careless or un-safe in your construction or sequencing - NO! We are saying that you need to keep your head screwed on and be aware of the tendency to "make it perfect" or this hobby will absolutely eat-up all of your available time.
- Okay, you've been warned...