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December 17, 2010
by Steeldeal
Steeldeal's Avatar

After reading through the Nerdkit guide and finishing the first two projects I'm kind of left with quite a few questions. Many things don't seem to really be explained well.

At first a lot of the programming was left unexplained. If I didn't have, albeit limited, programming experience I'm not sure I would have picked it up. Although later I notice some things being explained, that kind of needed to know earlier on I thought.

One question I have is about Amps. I want to add a DC wall transformer as power. But none of the information or the datasheets seem to talk about Amps. From what I can tell I can hook up my 12V transformer and it should work. But the voltage regulator doesn't say how many Amps is too little or what would be too much. It says it can handle 8V to 30V I think, but nothing on the Amps. It says it can output 1 Amp, but nothing on the input. On the Atmel MC datasheet it talks about how many amps it will consume, but not what it needs or how much would be too much.

Is Amps just a moot point? If I hook up the 12V 200 mA transformer is that too little? To Much? Doesn't matter?

Another question is that the Nerdkit just seems to leave a lot of things hanging. What about the MicroControllers? I'm fine buying MC's from NerdKit to support them while I'm tinkering but what about the others out there. Like you can find the Atmel168 and 328 all over the place. Some have no bootloaders, not sure how to get a bootloader on it it's only briefly mentioned and not explained. Some have Arduino bootloaders. What does that mean? I assume Nerdkits come with a custom bootloader. So is none of this really applicable outside these projects? Will I have to learn a different system or something? Or what effect does the bootloader have? Kind of confused there.

Also, just on MC's in general. I see Arduino boards out there. I see PIC, Atmel, all kinds of different things. Is the general basis the same? Or completely different especially since they would have different boot loaders?

I guess I just expected a little more learning? Only 3 projects really. I looked at the deal with the servo and squirter. The video doesn't explain anything at all it seems. They even appear to be controlling the device with their computer. Hold up, I don't think I learned anything about sending commands through the computer, I only learned about compiling the code. Again confusing.

There is a SparkFun Arduino Kit that is only $95, which covers 12 projects. Including servo, motor, generally a lot more stuff to work with and learn about. At least a lot more than just the 3 projects I have here, and only vague videos to continue with anything else. Am I missing something? Where do I need to look next?

I guess just feeling a little lost, like this was just barely a tease, only learning some very rudimentary basics, with several gaps it seems. Like Amps, if that's not important or whatever is that just supposed to be understood? Or did I miss something in the guide?

December 17, 2010
by hevans
(NerdKits Staff)

hevans's Avatar

Hi Steeldeal,

Welcome to our forums. I'm glad you have a lot of questions, you are well on your way to gaining a deep understanding of all these fun components you can work with.

You have a great question about current. Current needs to be thought about a little differently than voltage because you don't really put a current across a device like you would a voltage. Instead you think of current as going through a device, or a device drawing a certain amount of current. When your AC adapter says 200mA it means it can source 200mA at 12V. If you try to draw more current than that its supply voltage will drop, and eventually it will just turn off all together and stop supplying power. When the 7805 says it it can only handle 1Amp of current it is saying that only 1Amp can safely pass through it before it overheats. With the 9V battery that is not really a problem since the battery can not source that much current, with the AC adapter however, it is much more likely you might be able to draw that much current (since it is connected to the wall socket which can definitely supply that much current). On the device's side it matters how much current you plan to draw. You can look at the current draw that the MCU can do from the datasheet. This basically means given it has enough voltage to operate, it will be drawing this much current. Now the amount of current being drawn will vary depending on how many pins you have sourcing current to other things like LEDs (that can draw upwards of 30mA each). Of course things like accidentally shorting a lead or wiring something wrong can result in your device drawing a lot more current that you intended. Does that make sense? I'd be glad to attempt to explain a different way if you are still confused.

There is a custom bootloader on the chips we send. The reason for the bootloder is so that our customers have the ability to program the chip over the serial/usb cable without any additional hardware. The bootloader basically turns on the serial module on the chip and communicates with avr-dude over the serial port to bring the new program across. There are other bootloaders out there that work just as well, but they all ultimately do the same thing. We include the bootlader we provide as part of the source code, and I can give you instructions on how to program the bootloader onto fresh chips if you have a parallel port. There is also special hardware you can buy (and several threads on the forums on how to use them) to program the chips directly without a bootloader, and you can also use that hardware to flash the bootloader on.

There are tons of different microcontrollers out there. Some are good for some things and some better for other things. We believe the Atmega168 is a good all around microcontroller, and the concepts you learn while working with it will apply to any other embedded system you decide to use in the future. Yes some of the mechanics will be different, but the core ideas will always be the same.

The guide itself does not go into how to communicate over the serial port with the PC. However like you mentioned, the Servo Squirter tutorial does. If you have any questions about it, feel free to ask there are plenty of folks on the forums willing to help.

We tried to structure on curriculum to give you the basics you need to move up from. In the three projects detailed in the guide you learned about digital inputs and outputs, how to read sensors using the ADC, and how to set and read registers on the chip which in turn run everything on board your chip. Plus all the basic electrical knowledge that makes it all work. From here we hope you take what you have learned and apply it to your own ideas, projects, or modifications of our tutorials that interests you.

It is not until you actually have to use the things you have learned in a project that it will all start to firmly click in place, so I encourage you keep going, and keep asking the questions that pop into your head. There is no possible way we could have fit all the things you can do with the kit into a book, or cover all the questions that you guys will have. The fact that you have all these great questions is a clue of how much you have learned so far.

Of course if you are truly dissatisfied with your purchase I don't want you to feel like you have been cheated out of your money, feel free send us an email at support at nerdkits dot com and we can arrange to have you send your kit back.

Humberto

December 19, 2010
by Steeldeal
Steeldeal's Avatar

I'm not dissatisfied with the purchase. I think the system as a whole is really awesome. It has some great pieces to the kit and a lot of doors are opened. I think that just after reading the guide I kind of felt like, huh? That's it? That's all I'm taught. And it's basically before actually looking at the supporting forums and additional tutorials that it feels shorted. But with the supporting materials such as the forums and the growing tutorials on the site, I guess the Nerdkit is just that . . . the basic building blocks, the supporting materials provide the growing wealth of education. From there using the supporting online materials you can go where ever you want, you can learn in which ever direction is most interesting. Unlike other kits that might have 12-14 set devices that you can build whether you like it or not, the Nerdkit is much more customizable so to speak beyond the first 3-4 lessons.

I think I'm getting it with the Amps. It's not about what you are sending at it. It's more just what the device that you build is going to need. Then you have to know: A) does the power supply offer that much and even more importantly B) are the elements of your device (aka voltage regulator) have the ability to allow that much to pass through it. If your device breaks down at A then it won't work because there isn't that much available, and if your device breaks down at B it can be much worse with an overheating voltage regulator.

The questions keep growing and growing, the course, and more importantly the support available is worth more than the price of the Nerdkit.

I'm going to try and pick projects that I can use to learn the answers to my questions and use the forums only when I get stuck.

Thanks for your response Humberto.

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