26 December 2013

Customer Question: How many lights can be hooked up to the TinyPix?

HolidayCoro sales/support often sees common, open-ended questions from our customers and here on our blog we post detailed responses publicly so that other people will be able to learn from the decision making process we use to answer these questions.

Today's question is:  "I see that the smart pixels 8mm come in a max of 100 per string, however a TinyPix can control up to 170 pix. So if I wanted to control 150 8mm smart pixels, can I do that with one TinyPix? If so, how would the 2 strings (100 & 50) be hooked up to the TinyPix, and what kind of power supply would be required? (I assume the 45w one would be too small for 150 8mm Smart Pxels)."

I can see that the customer understands that the TinyPix controller can handle 170 pixels (510 DMX channels (170 * 3) or almost a full DMX universe that is 512 DMX channels) as that is covered in our documentation on the product page.  I can also see that the customer is aware from the product page for the 8mm smart pixel nodes that the pixels come shipped in 100 count maximum per string.  So, we have several issues here, some of which we have information on and some we don't.

Design - There isn't any design information provided, so we don't know if these are being used in a concentrated matrix or string over a long distance, such as a pixel tree or a soffit on a house.  Why this matters is because if the pixel nodes are all close together, it can be fairly easy to inject power (more on that in a minute) as where if they are in a long single string over a distance, it can be harder/more complex to inject power.  Additionally, we don't know if this is for a single element or many elements and the distances of those elements.  We would be generally suspicious if the TinyPix is even the correct item for this design because we suspect that it would be one of several units where a centralized pixel controller would be a better match.

Signal - A TinyPix controller is a RS-485 based controller and thus needs a DMX source, such as our Actidongle.  A single Actidongle could output 512 channels, so it could handle the 150 pixels (450 DMX channels) without issue - IF - the customer only has one of these items with such a high channel count.  If the customer has several other 150 pixel elements, they would need more DMX dongles and at some point it is likely cheaper to invest into a centralized pixel controller with a E1.31 inface.  Again, since we don't know anything about the overall design the customer has in mind, we can't recommend a specific solution here or if the TinyPix is even the right item for this customer.

Power - An important part of any RGB design is power management - we've covered this in many articles and knowledge base articles.  So, given that we know we are going to have problems if we try hooking more than 150 pixels together end-to-end from a power loss standpoint, we recommend the customer review our blog post about how to manage power injection and power supply selection (because the customer had also asked if the 45w power supply was sufficient to power them.)

So, to recap - yes, the pixels can be connected end-to-end in an amount UP TO 170 but just because that can technically be done by soldering the wires together to make a single length, doesn't mean they will work without managing the power issues.  The issue at hand is that there will be just too much power drop over the pixel wiring and thus power injection would need to take place, likely at the start (through the controller power outputs) and again at the end of the string.  This is what we recommend with our 163 and 150 pixel scrolling RGB matrix signs since it is easy to put power in at both ends of the wire, thus resolving the power drop issues since everything is close together.  If the pixels were used on, say, the front of a house or to outline windows, you'd need to still carry the power to the end or middle of the string for power injection.

The second part of the customer's question if our 45 watt power supply will be able to power all 150 nodes.  So, first we need to look at the overall power consumption of the nodes, which is:  White (all three colors) 100 Nodes: 3.6 amps / ~44 Watts  We can see right away that at 44 Watts for 100, that a 45 Watt power supply isn't going to cut it since 44 (100 nodes) + 22 (50 nodes) would be 66 Watts total, plus add in another few Watts for line losses and a safety factor and we are up towards about 75-80 Watts to be safe.  This excludes looking at any other factors such as additional controllers, etc - hence, why it is good to know the overall design involved.  So, normally I would just recommend hooking up a 250 to 350 Watt power supply.  They are not that expensive and likely the customer also has other controllers that could also piggy-back off this same power supply.

So, in conclusion - the customer would best benefit by providing as much detail as possible about the overall scope of the project and where this specific element fits into that project.  We understand that often customer just want a simple answer to their question and do not yet understand the underlying complexities that comprise an important part of the decision making process.  In this case, it would be helpful if the customer were to review and then understand the power and DMX addressing issues under-lying the technology in the TinyPix (and all DMX controllers.)  While this process can be long and tedious - taking weeks or months for some customers, this knowledge is a fundamental requirement for customers selecting a completely DIY solution, as we talked about in our DIY vs Commercial solutions blog post.

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