Hi Pascal,
This opens up more possibilities for us looking at getting a more reliable
control over 1wire. Distribution of control via the AE in the BAE0910 will
be great. The weak link I have in my system is obviously the reliance of
the 1wire master / script running in the host. It just so happens I am
currently building another automated aquarium for a small reef tank right
now. I thought if I explained the application after having a skim read of
capabilities of the BAE0910 you maybe able to comment on the feasibility...
A major advantage I see in 1wire over a PIC is the simple wiring and as such
want to try and keep the component count down and thus reliance on soldering
techniques. Don;t get me wrong I have built lots a of "bird nest" style
controllers in the past and studied electronics however I want to create
something that isn't too hard for anybody to build within the Aquarium
World.
DIGITAL CONTROL OF RELAYS
Requirements: Generally the digital control is a glorified light timer.
Currently thoughts are to simply use "cron" to start a simple 1 line script
to open or close various relays throughout the day. Typically require 8 or
12 relays however the relay boards are in groups of 4. I use a futurlec
board (US$15.00) 10Amp relays, opto isolated and includes all pull up
resistors etc etc. i.e. currently use a DS2408 direct to relay board.
Possible enhancements using a BAE0910.
Local control. I would like to be able to use 4 push buttons and when
pushed, toggle the corresponding output. This means if the host is down I
can still walk up to the tank and manually control each output. I propose
to use 4 switches / resistor network in parallel on the ADC line so the
wiring to the push buttons is simplified. Thus the push buttons or host can
control the output. The only complication maybe that the host would set a
parameter to 0 or 1 for on/off and the push button is a momentary pulse that
needs to toggle the same parameter as the host.
Failsafe......A future enhancement, I would like to send a watchdog pulse
from the 1wire host to the BAE0910, say every minute. If the BAE0910 does
not see this pulse (leading edge) in say ~30 minutes, it assumes the host is
down and the outputs go to a pre-configured failsafe position for each of
the four outputs. In this mode the push buttons would work as normal and
just toggle the corresponding output, manual control. When the host is
back, watchdog is sensed, the outputs simply stay at there current position
waiting for host control if required, which is called bumpless transfer.
Timed output....In one case I want to turn a pump off when feeding the fish.
That means from a push button I want to control an output and turn it off
for say 15 minutes when the leading edge of the button is sensed.
Questions:
1) Is the above feasible ?
2) Can I have 1 ADC and 4 DO
TEMPERATURE CONTROL
Requirements: To control the temperature of the aquarium. A heater with
inbuilt thermostat is used coupled with a Fan for cooling. On a hot day you
can get the heater fighting with the fan.
Simplified program
>27 (degC) Turn Heater OFF
>27 turn power to Fan ON
26 -28 modulate fan speed via PWM
<24 turn heater ON
<25 turn fan OFF
Auto / Manual.... From the host I would like to be able to set if the
temperature control scheme is in auto or manual.
In manual it means the host can toggle the corresponding outputs for heater
ON/OFF, Fan ON/OFF and fan speed via PWM value and the BAE0910 is just a
dumb device with PWM capabilities.
In "Auto" the AE has control of the outputs as per the table above and
ignores any requests from the host to override the outputs. I have assume
"Auto/Manual" can be an internal variable within the BAE0910 that can be set
from the host or internal AE.
Failsafe....Again like above with a watchdog pulse however in this case set
a pre-determined setpoint and force the AE into Auto control.
Timed Deadband.. Although not for temperature control, if the above was used
for pH control it is simple on/off control to dose pressurised Co2 into the
Aquarium.
example. >6.40pH output =ON <6.35pH output = OFF.
However the output cannot turn on again even if above setpoint for xx
minutes. Thus if the output is ON and the pH goes below 6.35 the output
turns off, even if the pH goes above 6.4 again the output does not go on
again until an internal timer has elapsed.
Questions:
1) Is the above feasible ?
2) Although I can use an RTD and transmitter to get 1-5VDC representing a
temperature signal, what I would really like to do is to direct connect a
single DS18B20 to the PIO pin and read temperature direct into the AE. i.e.
A single DS18B20 and only retrieve the temperature, no need for ID and all
that fancy stuff. RTD / Transmitter = $75.00 vers DS18B20=$5.00
2) Can the AE scale the ADC so we work in real engineering units ? or do I
work in 0-xxx counts. I would like to be able to send to the BAE0910 a
setpoint in degree's not counts and also read the value back in engineering
units.
3) Can I have 2 x DO and 1 x PWM output and 1 x ADC (or future DS18B20 using
a PIO pin :))
I have more applications however the above two would get me started.
Rob Conway
-----Original Message-----
From: Pascal Baerten [mailto:[email protected]]
Sent: Tuesday, February 02, 2010 10:17 AM
To: OWFS (One-wire file system) discussion and help
Subject: [Owfs-developers] Announcement for a new 1-wire slave device
BAE0910
Hi,
I'm pleased to announce the BAE0910, a new multifunction 1-wire slave
device!
Functions such pulse width modulation and embedded logic are now possible on
your 1-wire network.
The BAE0910 was the missing link of most 1-wire projects.
Main features:
* 1-wire compatible
* up to four PWM (pulse width modulation)
* one strong OUTPUT (sink/source up to 20mA)
* one PIO with integrated pull up/down
* one 32bit COUNTER input
* one 8bit ADC input with averaging & totalisation functions
* direct control of up to four R/C servo's
* 32bit RTC
* 1Kbyte eeprom
* 32byte user RAM
* AE AutomationEngine: embedded logic interpreter with four concurrent
instruction flows
* firmware upgradable via 1-wire
All theses features are integrated in a single soic-8 package with direct
connexion to DQ (require 5Vdc supply).
Complete documentation datasheet is available online.
Special thanks to Paul Alfille for integrating support of this device in
OWFS project and for the constant feedback he provided during development of
the device.
Starting on version 2.7p29, OWFS integrate support for BAE0910.
The BAE0910 chip is already available for order online and a tiny board
(13x36mm) integrating the BAE0910 is also availlable on preorder now.
Visit www.brain4home.eu <http://www.brain4home.eu/> for more info.
--
Pascal
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