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136  Development / Other Hardware Development / Re: Entry-level Oscilloscope on: February 22, 2011, 09:40:17 pm
At USD349, the Rigol 50 MHz DS1052E is awesome!
137  Development / Suggestions for the Arduino Project / Re: Timestamp option for serial monitor on: February 18, 2011, 08:01:39 am
You can just use Docklight for this purpose which came with time stamp interval configuration.
I guess adding too many feature to Arduino IDE will add more issues later.
138  Forum 2005-2010 (read only) / Troubleshooting / Re: Timer 2 Asynchronous and Sleep Mode on: September 13, 2010, 08:20:45 pm
Please read the contraints for deeper sleep levels.

I understand that asynchronous timer can be used to wake the MCU in power save mode which I have tested to work properly in plain avr-gcc.

Has anyone tried using a 32.768kHz crystal to wake the MCU in power save sleep mode?
139  Forum 2005-2010 (read only) / Troubleshooting / Timer 2 Asynchronous and Sleep Mode on: September 13, 2010, 09:36:31 am
I managed to get MsTimer2 library to run on an external 32.768kHz. It will generate a 1 Hz interrupt. From here, I can get to execute a task at a "x" seconds rate by using a seconds counter/multiplier.

Now, I want to add sleeping capability while Timer 2 still runs asynchronously from the 32.768kHz. I use the Sleep library together with the modified MsTimer2 library.  

But, when I put the MCU to sleep in SLEEP_PWR_SAFE mode, the MCU always fails to count the desired seconds (1 Hz Timer 2 interrupt x desired seconds) I wanted, other than the 1 second. It works fine if the sleep mode is set to SLEEP_IDLE.

I tested in plain avr-gcc, and it works fine for both idle and power safe mode. Has anyone tested the Arduino Sleep library under SLEEP_PWR_SAFE mode?
140  Forum 2005-2010 (read only) / Troubleshooting / Re: can arduino be powered by coin batteries? on: December 20, 2010, 01:22:06 am
You would have to go with simpler and basic Arduino boards like Pro Mini to do this. This is because most of the time, quite an amount of current is being used by the regulators itself (high quiescent current) and hence not suitable for small coin cell batteries. Even Pro Mini on board regulator might not be ultra low power (there's no manufacturer part number on schematic to verify this).
141  Forum 2005-2010 (read only) / Troubleshooting / Re: Wireless guidance ideas needed on: November 16, 2010, 04:18:36 am
The new revision of the 2.4 GHz XBee Pro is rated 3.2 km for LOS. I have tested them in a dense jungle and it works up to 500 m without any LOS. For other ISM band, I guess it would be easier to find those with long range depending on your location around the globe. smiley
142  Forum 2005-2010 (read only) / Troubleshooting / Re: Batterylife on: November 15, 2010, 07:33:59 am
just to be sure I understand: the regulator is not affected by the sleep as it's not a part of the mcu?

The regulator is not affected in this case. So even at light loads (MCU sleeps), the regulator still consume some mA to provide the necessary output voltage. But, this is not true for all regulator. Some more advance regulator has very low quiescent current; something in the uA range. In this case, it doesn't contribute much to the overall current consumption of the board. So, when the MCU enters deep sleep, the board really goes down to uA range.  smiley
143  Forum 2005-2010 (read only) / Troubleshooting / Re: Batterylife on: November 15, 2010, 05:56:09 am
You can get the MCU to go deep sleep to achieve uA current range for the MCU alone. But the regulator used in most of the Arduino boards design itself has quiescent current in the mA range.
144  Forum 2005-2010 (read only) / Troubleshooting / Re: Xbee multipoint on: September 07, 2010, 10:43:30 am
There's some control protocol between the 2 points on top of the application data that you send from the master to the other nodes.
145  Forum 2005-2010 (read only) / Development / Re: AtMega 328 availability? on: January 08, 2011, 10:22:33 pm

I have about 30 piece so ATMega328P-AU, if you want to buy a piece for me it's okay. But shipping from my place to yours using normal registered air mail cost about ~USD10.  smiley-sad
146  Forum 2005-2010 (read only) / Development / Re: AtMega328 with Internal 8MHz Oscillator Questions on: January 04, 2011, 10:05:29 pm
BTW, I did try the the new "ATmega328 on a breadboard (8 MHz internal clock)" (but only once), and I got errors while loading that bootloader. However, I should try it again to be sure.

I manage to do this using the same bootloader but I found that the fuse settings is not correct. It can only upload the sketch once. I changed the fuse setting but I have to dig back to remember which bit. But I used a custom made board.
147  Forum 2005-2010 (read only) / Development / Re: Femtoduino: ultrasmall arduino 20.7x15.2 mm on: December 30, 2010, 05:13:02 am
I designed one with a 0.5mm board-to-board connector before. Slightly larger than Femtoduino but have everything on board (FTDI, crystal). I guess the main idea was not to be prototyping friendly and but maybe for prototype stage, you can make a base board that breaks out to the standard 0.1" (something that stacks from the bottom).
148  Forum 2005-2010 (read only) / Development / Re: Voltage Regulators on: December 25, 2010, 03:35:14 am
Quiescent current is the operation current even when there's no load. Shutdown current the current consumed when the switch off control is applied. Some regulator can have uA range of quiescent current (usually switch mode based) and some have nA range for shutdown current.
149  Forum 2005-2010 (read only) / Development / Re: Free open source schematics drawing software... on: December 20, 2010, 01:02:21 am
I think no matter what package you use, it's best to stick with one and master it. Once you use it often, I don't think it would be a problem.
150  Forum 2005-2010 (read only) / Development / Re: Cheap PCB shop is the US?  suggestions on: December 13, 2010, 05:49:35 am
While I find  EEVBLOG generally annoying, his entry covering "design for manufacturing" covers the reasons for this quite well.

Argh... His voice is very disturbing... But his videos are all very informative!
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