Custom Microcontrollers

Discussion in 'The Projects Forum' started by Pawel19, Sep 1, 2012.

  1. Pawel19

    Thread Starter New Member

    Sep 1, 2012
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    I have seen people use microcontrollers with they're specific project name printed on the microcontroller. Are these fully customized boards or a generic board that was found and simply imprinted on? Where do you go about getting this done and is it expensive? Thanks!
     
  2. BMorse

    Senior Member

    Sep 26, 2009
    2,675
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    Can you elaborate a little more on the question? Do you mean they have the project name printed right onto the microcontroller used in the project or on the PCB that is used?
     
  3. donpetru

    Active Member

    Nov 14, 2008
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    If you want to learn microcontrollers, I recommend you start with Atmel AVR microcontrollers. For example, you can start to buy a motherboard application development EasyAVR6 from here:
    http://www.mikroe.com/easyavr/v6/
    Then study sites microcontroller datasheet. Depending on what you want to do, choose your microcontroller. After that it's important to choose your software, for example, you can choose something in C or BASIC.
     
  4. BMorse

    Senior Member

    Sep 26, 2009
    2,675
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    That is not what the OP is asking, he is asking about custom printed Microcontroller circuit boards.....;)
     
  5. Markd77

    Senior Member

    Sep 7, 2009
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    I'm just guessing, but I imagine the cost per part is pretty similar, but there will be a large minimum order quantity (I'm assuming you mean the microcontroller chip itself).
     
  6. Pawel19

    Thread Starter New Member

    Sep 1, 2012
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    Yeah, maybe just printing on the PCB would be a simpler solution, but I could look at minimum order numbers. Thanks!
     
  7. absf

    Senior Member

    Dec 29, 2010
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    You mean something like the attached picture?

    I ordered a few pieces of the chips from that shop and it seems like it was done in the factory (not silkscreened by the seller). I guess if you order in large quantity, the manufacturer would put anything that you requested on the chips.

    Allen
     
  8. WBahn

    Moderator

    Mar 31, 2012
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    If you are having a PCB made, then having your logo and whatever else you want printed on there is free, assuming you are going to have a silkscreen in the first place, which you probably will. Even if you don't, you can still put your information in the top/bottom copper planes. It will show through the soldermask just fine. If you want to make it really stand out, then block the soldermask and let it be tinned. The only thing you would need to worry about is if your design is operating in an RF realm where the stray metal would cause problems.

    As for the microcontroller, there are a lot of parts (not just microcontrollers) that are available as 'bare die' and which you have to then have packaged. As part of doing so, you then have basically the same options to have the parts marked as the manufacturer did. There used to be a good sized set-up charge because they had to physically produce a mask, but I don't know that this is a big factor these days since laser marking is so common. Some packaged parts may also be available in unmarked packaged, in which case you can take them anywhere you want and have them marked.

    But unless you really want to hide what parts you are using, I would recommend just having your information on the PCB.
     
    absf likes this.
  9. Pawel19

    Thread Starter New Member

    Sep 1, 2012
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    Thanks, lots of helpful info!

    A very noobish question, what are the major advantages of designing your own PCB? I'm assuming cost and unique solutions would be the answer, but it seems that with the high cost of PCB designing software (Eagle at least), that this wouldn't really pay off, at least for simple projects. So I'm guessing the main advantage is for complex unique solutions. Anyone care to learn me some?
     
  10. WBahn

    Moderator

    Mar 31, 2012
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    The best answer for this depends very, very much one what you are doing. First, there are a number of free PCB CAD software tools out there (doesn't Eagle have a free version? I don't remember). I use a 25-year old copy of a Win3.1 version of Protel that cost me $70.

    It all comes down to alternatives and the difference between NRE (non-recurring engineering) costs and production costs (the actual cost to produce each widget after the first one). If you are making one-off projects, then everything is NRE and it might well be reasonable for you to purchase a suitable evaluation board and use that as the heart of your design. But be aware that you are almost always paying a LOT for the handful of components that are on that board. But if you design your own board, you not only get to populate it with just the components that you really need, you also get to include any additional circuits or features that you want. You do have NRE, of course, and you have to weigh that against the number of units you are making.

    Let's take a hypothetical (and highly simplified) project.

    You have been asked to design something that your customer wants 10 of but, if they like them, they will want 100 more of. So you design the thing around a $200 development board that requires an additional $100 in parts. You have put 100 hours into the design and testing and another 50 into building the units and want to get paid $40/hr. So your costs for the 10 units total $9000 and you have to charge $900 per unit.

    Your customer is okay with this because they understand that prototypes cost a lot, but after evaluating the units they tell you that they love how they work, but can only justify buying the other 100 units if their cost is under $250/unit. You can't even buy your development board and other components for that. So what do you do?

    Consider this option: Let's say that you decide that you would have to buy a $2000 CAD package to layout your own board. You then spend 100 hours actually laying out the board (including learning the software well enough to do so). You then spend $500 for tooling to have a PCB manufacturer make and populate your boards. Your component costs are $70 per board (including the custom PCB) and the assembly of 100 boards costs you $1000. You now spend only two hours per board finishing things off and running some acceptance tests. So how much does each unit cost you? Well, you've got $2000 + $4000 + 500 + $7000 + $1000 + $8000 for a total of $22,500, or $225/unit. So, assuming I haven't messed up the math (and if I did I would just change some numbers to make them work out they way I want, of course) you can sell the 100 units to the customer for $250 and make an additional $2500 profit.

    What's more, notice that you paid for the entire CAD package with this one project, yet you'll be able to use it one many more projects in the future at no additional cost, not to mention that you won't spend as many hours to do the layout because now you know how to use it. So a more realistic way to consider the software cost is to estimate how many projects you will use the software on in the next three to five years. If you only do five projects a year that would benefit from having the software and you use a four year window, then you will have 20 projects to spread the cost over, or only $100 per project over many projects and not $2000 on a single project. If your average project needs ten boards, then your cost per board for the software is only $10.

    Another thing to consider is that many customers are favorably impressed when the prototype you show them is on a custom PCB that has their name on it. There are lots of reasons, sound and silly, for this. Some of it is just ego stroking, but it also creates an impression of competence and capability that leaves them with a feeling that you can deliver on the final product in a way that a kludged-together demo, no matter how well it works, just doesn't convey. If nothing else, it creates the impression that the hard part is over and you are just a couple steps away from the final product.

    I guess my final point is to not be too stingy with NRE costs that enhance your long-term capabilities (i.e., are going to be useful for many, many years on many, many projects).
     
    Pawel19 and absf like this.
  11. Pawel19

    Thread Starter New Member

    Sep 1, 2012
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    Wow, thank you WBahn, a great answer! The economics of design are something I'm very interested in and that was a great summation of a lot of assumptions I had made.

    To boot, my university has PCB design software so I won't be having to buy any anytime soon!
     
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