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Messages - KeithJRome

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TinyLily / Re: Pinout documentation
« on: July 08, 2013, 04:35:06 PM »

General Discussion / Re: Is TinyDuino appropriate for beginners?
« on: July 05, 2013, 06:22:19 PM »
Ken has another post on the forum that explains the pin layout in a pretty straightforward way:

I also have a wide range of programming language background, with most of my time over the last decade entrenched in .NET. Writing Arduino or native AVR code (I prefer the latter since the Arduino IDE is atrocious) is a nice break from that. Plus I've really been enjoying learning Verilog HDL for my fpga board, which is entirely unlike any software programming that I have ever done.

You'll probably find it very easy to ramp up on the Arduino platform - it was designed to be approachable by non-programmers, so those of us with a programming background have a bit of a leg up already.

General Discussion / Re: Is TinyDuino appropriate for beginners?
« on: July 05, 2013, 10:26:48 AM »
It also depends a lot on what kind of programming you have been doing. If you use C/C++ a lot already, then you will find it very easy and might outgrow a standard Arduino in just a day or two. On the other hand, if you're not very familiar with C or have never done bitwise arithmetic, then you might benefit from spending some time with a standard Arduino first while you go through the tutorials on and get a feel for the language and how to interface with the hardware.

Of course standard Arduino UNO are pretty cheap and it doesn't really hurt to have one around anyway.

General Discussion / Re: tiny screen/Display
« on: July 03, 2013, 06:00:51 PM »
I'm impressed. The image quality is a lot better than I presumed it would be. Almost looks like it was made to fit the TinyDuino boards.

General Discussion / Re: tiny screen/Display
« on: July 02, 2013, 03:16:54 PM »
No, I have not. I would caution you though about relying too much on the images shown in those listings. The one with the fish photograph looks very suspicious to me. I think it was photoshopped. The others might be more reasonable, but still... I just wouldn't trust the product pictures.

General Discussion / Re: tiny screen/Display
« on: July 01, 2013, 10:30:39 PM »
This one is 3.3v / 20mA. It is 28mm x 28mm, so slightly larger than what you want:

This one is slightly smaller, but might need a little more effort on the programming side (also wants 3.5v for the backlight instead of just 3.3v like on the logic pins):

If your pockets are deep, then there are also these which all seem to be in the size range you are looking for (although not very thin):,fff80276,ffec322b&stock=1

Lastly, there are a couple of displays from Adafruit which might be suitable. They tend to be slightly larger than 20x20, but maybe that is OK for your needs:

None of those screens will have the Tinyduino connector - you would probably need to make a small board for any of them, or possibly wire it up to a Tinyduino Protoboard.

TinyDuino Processors & TinyShields / FTDI driver causing crash?
« on: June 09, 2013, 10:17:46 PM »
Just wondering if anyone else has seen this or if it was an isolated incident...

I was messing around with my TinyDuino, just toying with a few simple sketches and the led board. Everything worked fine until I unplugged it from the USB cable, which triggered an instant kernel panic / system crash in OS X. The FTDI driver was right at the top of the crash report when I restarted.

I had been playing with my TinyLily too prior to this (which uses same driver and same settings), and didn't have any trouble upon disconnecting that one. I've also been doing a fair amount of tinkering with both my Arduino as well as my Mojo FPGA with no stability problems.

Is this maybe just a rare bug in the FTDI driver? If it is semi-common then I will need to be more careful about when I tinker with these boards so I don't lose any real work when it takes down my other software.

I thought pretty much the same thing and was hoping to find time to design a small self-contained power source using one of those tiny energy harvesting ICs from Linear Tech once I get my boards in.

The tricky thing is that with such a small trickle of power coming in, you probably can't run the project full-time. It would need to spend most of its time in a low-power sleep mode to conserve charge. This isn't a big problem when programming AVR microcontrollers directly, since I think pretty much all of them support light and deep sleep modes, but I'm not sure how it would work when using Arduino libraries (perhaps it's exactly the same).

Piezo/thermal energy sources could also be interesting.

General Discussion / Re: USB & ICP board mosfet question
« on: April 17, 2013, 02:39:48 PM »
Is the power supply shield something that is coming? I don't recall seeing anything like that mentioned before (but it makes sense to have one, especially if it utilizes an external LiPo battery.

And am I correct in interpreting this correctly - that when a coin cell battery is in use (and no "power shield" or USB/ICP shield is present), the only energized rail would be VCC (and BATT I guess), but it could be as low as +2.7v? So if we need to run anything sensitive enough to care about the difference between 3v and 5v then we would need either a secondary regulated power source or add a boost converter?

User Projects / Code Examples / Re: TinyDuino POV
« on: April 15, 2013, 01:15:34 AM »
That's pretty cool!

General Discussion / Re: How secure does this forum have to be?
« on: April 14, 2013, 05:36:10 PM »
Unfortunately, the spammers had found this forum and started spamming it within days of initial launch.

That said, I haven't seen the captchas or security questions while posting. So it hasn't been a nuisance at all for me. I do have it set to always remember me though - perhaps that has something to do with it? Or perhaps the prompts stop once you have posted some minimum number of times without being banned?

For example, with this post I didn't need to jump through any hoops. Just click Reply, type some text, then hit Post or Preview.

General Discussion / Re: USB & ICP board mosfet question
« on: April 11, 2013, 09:35:54 PM »
I think what is happening with that transistor is that when VIN is grounded or left floating (in which case R3 pulls it low), Q1 is closed circuit (FETs are normally closed, the opposite of BJTs). Since USBVCC is connected to the USB connector, then the +5V net will effectively be connected to +5 power supplied by USB (if plugged in to a USB power source). When VIN goes high, the FET is open circuit and the +5V rail is no longer connected to USBVCC source. This would agree with the notation in the ISP Shield spec that says "Will supply +5V to the system if VIN is not present". It looks like nothing is normally connected to VIN (pin 10 on the shield connectors), so unless you go out of your way to apply a voltage to that pin, +5V will always be live (if connected to a USB host or hub).

I think maybe the purpose of the VIN signal is if you wanted to provide your own +5v power source, and keep it isolated from the USB link. Like maybe if you needed to drive more amperage than you want to pull from the USB source (i.e. anything over 500mV). In that case, you could just wire your power source to the +5V net (pin 8 on the shield connector) and pull VIN high (pin 10 on the connector). Or if you needed a non-standard voltage such as 4v.

Then there is a power module on the Processor unit that appears to select either VBATT or +5V as the VCC source to power the microcontroller (also used as analog and I/O reference voltage). What it looks like is happening in that module is that VBATT is used for VCC unless +5V is there. If +5V is present, then the top half of Q1 (not the same as "Q1" in the ICP board!) is suppressed, which closes off VBATT from VCC, leaving +5V attached to VCC.

VBATT is of course 3v since it is a coin cell, so it seems like the system can end up running on either 3v or 5v, depending upon which power source(s) are hooked up. For the MCU that's OK, but it also means that peripherals would also need to be able to handle both +3 and +5 volts I think? That seems wrong - wouldn't the voltage jumps potentially cause unexpected behaviors... such as overdriving LEDs (or worse)?

Another thing that looks odd is that we have a +3v3 pin on the connector (pin 6), but I don't see where this is used or supplied anywhere? Pin 16 of the FT232R chip has 3v3 output via LDO regulator, but that can only drive up to 50mA, and it doesn't show as being connected to that net anyways. So that seems a little bit weird.

New Product Ideas / Re: SRF Shield (Wireless module, RFM12B Compatible)
« on: November 28, 2012, 01:43:54 AM »
Hmm looks interesting. That's some serious range capability. Some questions:

1. Would the price be comparable with the existing product you are offering? (approx

New Product Ideas / Camera shield
« on: October 25, 2012, 03:48:00 AM »
Natural color and/or IR camera shields. There are some really interesting and cheap tiny cameras on sparkfun that appear to be small enough to easily work in TinyDuino projects. Possibly even some TinyLily projects as well.

I can think of many uses for such a shield, such as surveillance applications and vision processing experiments.

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