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1  Using Arduino / Motors, Mechanics, and Power / Re: Motorized Valve on: April 17, 2014, 10:08:50 pm
For your application of routing flow from one to two different directions requires a 3-way valve, so called because it has three connections, one for inlet and two for outlets. I would assume you would continue to use the existing manual valve to control the actual flow rate as you shower, with the new 3-way value installed upstream to just direct flow to storage or shower valve, and as such would probably be cheaper (relatively, still not cheap due to port size) to use a 3-way solenoid valve and therefore control would be much simpler and cheaper power mosfet switching transistor controlled by the arduino.

The more expensive route would be a quarter turn 3-way ball valve mechanically coupled to a high torque servo but I'm sure that would be much more expensive then the 3-way solenoid valve. If using a solenoid valve be sure to use a 12 or 24 vdc coil rather then mains powered as water and mains power can be a dangerous combination and probably not legal for DIY installations.

 The more professional solution is to install a whole house instant hot water function where there is small continuous flow from the hot water heater to all the service locations with a return loop back to the water heater But that is not a simple DIY project and needs lots of pipe insulation and other details to keep the energy costs under control.

2  Using Arduino / Project Guidance / Re: Blocking -VDC on: April 17, 2014, 09:42:33 pm
Ok, I've just never seen that configuration used. Funny how many words it takes to describe what a simple schematic drawing might make obvious.  smiley-wink
 
3  Using Arduino / Project Guidance / Re: Ground-side switch output? on: April 17, 2014, 03:37:20 pm
Might need a more detailed example of what you need, but standard arduino output pins can both source (when HIGH) and sink (when low) current, but with a current limit of 40 milliamps absolute maximum. If higher current is required then additional output components are required, like mosfet switching transistors that can be configured for high or low side switching.

4  Using Arduino / Project Guidance / Re: Blocking -VDC on: April 17, 2014, 03:28:26 pm
Just commenting on the idea of using a motor as a generator to determine direction:

Connect one terminal of the motor to a voltage divider at Vcc/2. Connect the other, through the appropriate resistors and diodes to protect the Arduino and capacitor to smooth the signal, to an Analog input pin.

Motor spins one way, voltage>2.5V. Motor spins the other way, voltage<2.5V. You could connect a second Analog input to the voltage divider to get an accurate read of zero speed voltage.

Load the motor down with the right resistor across it, and you can probably get a reasonable indication of speed, too. The resistor should go right across the motor.

 That doesn't sound right to me. A DC generator to turn in both directions must cause the voltage to change polarity, so voltage output of your 'simple method' would be some positive voltage in one direction depending on speed, and the same voltage but negative if driven in the opposite direction at the same speed. And as arduino analog inputs can not measure negative voltages, how could it work?
 
5  Using Arduino / Audio / Re: Small Class D amplifier on: April 17, 2014, 03:12:41 pm
wow that's a lot of sources quick, thanks guys!  I'll take a look at em now. 

@retrolefty and DVDdoug:  I meant put the speakers in parallel, not the amps, so I can drive more power at the same voltage.  However since class D amps are 'digital' I figure they are a bit harder to predict how they will behave outside of thier rated range of loads compared to AB amps.  Gotta dig into the datasheets to konw for sure.  stupid low voltage supply, BUT since it is so close to automotive range, I know there must be devices out there specifically for it.

 Well keep in mind that 'digital' class D amps are still analog as seen by the speaker loads as there is a low pass filter output stage on any audio class D amp.
 Also halving the speaker impedance does not automatically double the output power unless the amp is rated for the increased current demand for the decreased speaker impedance. The datasheet for the amp chips should always be studied to determine what actual power output you can get at a give device voltage and speaker impedance. There is more to it then simply ohm's law.  smiley-wink
6  Using Arduino / Project Guidance / Re: Arduino Nano as USB HID on: April 17, 2014, 02:59:50 pm
Not possible with a Nano as it uses the special purpose FTDI chip to perform the USB serial interface, not a programmable AVR chip such as the 16U2 chip the standard Uno board uses.
7  Using Arduino / Audio / Re: Small Class D amplifier on: April 17, 2014, 02:41:06 pm
Quote
i am hoping I can put several in parallel to dropthe eff resistance to whatever the minimum the amp can handle
A Bad, bad, bad, idea! smiley-sad   The general rule is NEVER connect outputs together. (That's why you use an audio mixer to mix audio signals.)   Solid state amplifiers have very low internal source impedance (often less than one Ohm).   The output of one amp "shorts out" the output of the other.

The most common "trick" is to make a bridge amplifier.    That doubles your peak-to-peak output voltage (theoretically 26V P-P = 9V RMS) with a 13V power supply) and that gives you 4 times the power into the same load.  Doubling the voltage doubles the current, so an 8-Ohm speaker "looks like" a 4-Ohm speaker to each amplifier.   In theory you can get about 10W into 8 Ohms, but there is some voltage drop across the transistor/MOSFET and you can't actually get the full power supply voltage across the speaker.

High power automotive amplifiers have a voltage-boosting power supply.



 And for 'bridging' to work the audio signal input must be inverted 180 degrees in one of the amps.
8  Using Arduino / Microcontrollers / Re: Unable to use USBtinyISP on a bread board ATMega328p set-up on: April 17, 2014, 02:31:04 pm
Your welcome. Keep in mind that the mega1284P chip has the same DIP pin-out as the 644P with a big increase in SRAM capacity of 16KB and other goodies. I have a optoboot for it also if you ever need it.

Yes, please!  (Is it different from maniacbug's?)

I've seen two different bootloaders for the 1284P so not sure which is maniacbug's.

optiboot_atmega1284p

Quote
:020000000504F5
:020000021000EC
:10FC00000F92CDB7DEB7112484B714BE81FFF1D0B7
:10FC100085E08093810082E08093C00088E180933A
:10FC2000C10086E08093C20080E18093C4008EE032
:10FC3000CAD0209A26E080E39CEF31E090938500C3
:10FC40008093840036BBB09BFECF189AA8952150B4
:10FC5000A9F700E010E0EE24E394E1E1DE2EF3E00A
:10FC6000FF2EA5D0813471F4A2D08983B2D08981CE
:10FC7000823809F48BC0813811F484E001C083E03C
:10FC80008FD08BC0823411F484E103C0853419F421
:10FC900085E0A7D082C0853591F489D0A82EBB24F9
:10FCA00086D0082F10E0102F00270A291B29812F4A
:10FCB000881F8827881F8BBF000F111F6DC08635D6
:10FCC00021F484E08ED080E0DBCF843609F040C0A0
:10FCD0006ED06DD0C82E6BD080EE0030180718F4AF
:10FCE000F801F7BEE895A12C51E0B52E60D0F501E2
:10FCF00081935F01CE16D1F7F0EE00301F0718F0A8
:10FD0000F801F7BEE89565D007B600FCFDCFF80115
:10FD1000A0E0B1E02C9130E011968C91119790E029
:10FD2000982F8827822B932B12960C01E7BEE8951B
:10FD30001124329682E0A030B80761F785E0F8011F
:10FD400087BFE89507B600FCFDCFD7BEE89525C074
:10FD50008437A9F42CD02BD0B82E29D03AD0CB2C74
:10FD60004801F40186911CD00894811C911CCA940E
:10FD7000C1F70F5F1F4FBA940B0D111D0EC08537D1
:10FD800039F427D08EE10CD087E90AD085E078CF0E
:10FD9000813511F488E017D01CD080E101D061CF0B
:10FDA0009091C00095FFFCCF8093C600089580918C
:10FDB000C00087FFFCCF8091C00084FD01C0A895E2
:10FDC0008091C6000895E0E6F0E098E1908380839A
:10FDD0000895EDDF803219F088E0F5DFFFCF84E190
:10FDE000DFCFCF93C82FE3DFC150E9F7F2DFCF9128
:0CFDF000089580E0E8DFEE27FF2709946B
:040000031000FC00ED
:00000001FF
Quote

And boards.txt entry for it:

Quote
##############################################################

bobuino.name=Bobuino 1284P optiboot
bobuino.upload.protocol=arduino
bobuino.upload.maximum_size=130048
bobuino.upload.speed=115200
#bobuino.bootloader.low_fuses=0xff
bobuino.bootloader.low_fuses=0xf7
#bobuino.bootloader.high_fuses=0xde
bobuino.bootloader.high_fuses=0xd6
bobuino.bootloader.extended_fuses=0xfd
bobuino.bootloader.path=optiboot
bobuino.bootloader.file=optiboot_atmega1284p.hex
bobuino.bootloader.unlock_bits=0x3F
bobuino.bootloader.lock_bits=0x0F
bobuino.build.mcu=atmega1284p
bobuino.build.f_cpu=16000000L
#bobuino.build.core=arduino:arduino
bobuino.build.core=standard
bobuino.build.variant=bobuino


##############################################################
9  Using Arduino / Microcontrollers / Re: Unable to use USBtinyISP on a bread board ATMega328p set-up on: April 17, 2014, 02:25:37 pm
Quote
The AVRDUDE program used in the IDE has a config file of the signature bytes it's expecting to find when it interrogates the chip. 

config.txt ? (in Hardware folder ?)

Named avrdude.conf and buried somewhere in the arduino core directories.
10  Using Arduino / Microcontrollers / Re: Unable to use USBtinyISP on a bread board ATMega328p set-up on: April 17, 2014, 12:13:49 pm
Quote
 Checked the signatures are the same on both MCUs 0x000, 0x0002, 0x0004, 0x0001 so that will be ok.
Where do you check this ? (how do you check it ?)

 They are given in the specific AVR datasheet for the chip. The AVRDUDE program used in the IDE has a config file of the signature bytes it's expecting to find when it interrogates the chip.


11  Using Arduino / Audio / Re: Small Class D amplifier on: April 17, 2014, 12:12:44 pm
Maybe search out the datasheet for the PAM8610  chip used in module like this:

http://www.ebay.com/itm/Digital-Amp-Audio-Amplifier-Module-10W-10W-2-Channel-Class-D-/221239184525?pt=US_Home_Audio_Amplifiers_Preamps&hash=item3382e20c8d
12  Using Arduino / General Electronics / Re: How do I replace a moral rectifier part? on: April 17, 2014, 12:07:21 pm
Arduino just for blog cred.  smiley-grin
13  Using Arduino / Microcontrollers / Re: Unable to use USBtinyISP on a bread board ATMega328p set-up on: April 17, 2014, 11:59:59 am
Your welcome. Keep in mind that the mega1284P chip has the same DIP pin-out as the 644P with a big increase in SRAM capacity of 16KB and other goodies. I have a optoboot for it also if you ever need it.

Lefty
14  Using Arduino / Installation & Troubleshooting / Re: Sketch-Upload via USB/ TTL-Adapter does'nt work ... on: April 17, 2014, 11:38:41 am
Are you relying on the IDE autoreset function or are you using a 'well timed' manual reset method? Many people trying to use those
PL2303 won't work as the signal name reset on those modules are not the DTR or RTS signal needed to pulse the arduino module. You can hack the PL2303 sometimes depending on board layout of the module.

15  Using Arduino / Microcontrollers / Re: Unable to use USBtinyISP on a bread board ATMega328p set-up on: April 17, 2014, 11:20:59 am
Quote
Which bootloader and board description to use is my next quest!

For the 644? If so I use opto version set up for 16mhz named  optiboot_atmega644p-4-5.hex, as it's the smallest and fastest baudrate, handles WDT interrupts properly, etc.

Code:
:020000000504F5
:10FC0000112484B714BE81FFF2D085E08093810077
:10FC100082E08093C00088E18093C10086E08093F9
:10FC2000C20080E18093C4008EE0CBD0209A86E0B1
:10FC300020E33CEF91E0309385002093840096BB55
:10FC4000B09BFECF189AA8958150A9F7CC24DD244B
:10FC500088248394B5E0AB2EA1E19A2EF3E0BF2E69
:10FC6000A4D0813471F4A1D0082FB1D0023811F49E
:10FC700085E005C0013811F484E001C083E08DD037
:10FC800089C0823411F484E103C0853419F485E01D
:10FC9000A6D080C0853579F488D0E82EFF2485D0A1
:10FCA000082F10E0102F00270E291F29000F111F09
:10FCB0008ED068016FC0863521F484E090D080E05A
:10FCC000DECF843609F040C070D06FD0082F6DD0E1
:10FCD00080E0C81680EED80618F4F601B7BEE895A5
:10FCE000C0E0D1E062D089930C17E1F7F0E0CF16C5
:10FCF000F0EEDF0618F0F601B7BEE89568D007B65B
:10FD000000FCFDCFA601A0E0B1E02C9130E01196FF
:10FD10008C91119790E0982F8827822B932B129625
:10FD2000FA010C0187BEE89511244E5F5F4FF2E0A7
:10FD3000A030BF0751F7F601A7BEE89507B600FC53
:10FD4000FDCF97BEE89526C08437B1F42ED02DD0D4
:10FD5000F82E2BD03CD0F601EF2C8F010F5F1F4FF8
:10FD600084911BD0EA94F801C1F70894C11CD11CFE
:10FD7000FA94CF0CD11C0EC0853739F428D08EE10F
:10FD80000CD086E90AD08AE07ACF813511F488E078
:10FD900018D01DD080E101D063CF982F8091C00092
:10FDA00085FFFCCF9093C60008958091C00087FF27
:10FDB000FCCF8091C00084FD01C0A8958091C60051
:10FDC0000895E0E6F0E098E1908380830895EDDF08
:10FDD000803219F088E0F5DFFFCF84E1DECF1F939A
:10FDE000182FE3DF1150E9F7F2DF1F91089580E04B
:08FDF000E8DFEE27FF2709946C
:040000030000FC00FD
:00000001FF


And from my boards.txt file:

Code:
##############################################################


bobuino644.name=Bobuino 644P optiboot
bobuino644.upload.protocol=arduino
bobuino644.upload.maximum_size=63488
bobuino644.upload.speed=115200
bobuino644.bootloader.low_fuses=0xff
bobuino644.bootloader.high_fuses=0xdc
bobuino644.bootloader.extended_fuses=0xfd
bobuino644.bootloader.path=optiboot
bobuino644.bootloader.file=optiboot_atmega644p-4-5.hex
bobuino644.bootloader.unlock_bits=0x3F
bobuino644.bootloader.lock_bits=0x0F
bobuino644.build.mcu=atmega644p
bobuino644.build.f_cpu=16000000L
#bobuino644.build.core=arduino:arduino
bobuino644.build.core=standard
bobuino644.build.variant=bobuino

##############################################################

But be aware that the bobuino uses a different pins_arduino.h file as he changes some of the pin layout to better match the standard shield layout.
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