A 100 ohm add-in resistor produces an acceptable LED brightness. This is perhaps the minimal brightness. Current draw is from 4mA to 13mA, still quite high.
A 150 ohm resistor produced a dim LED at 12mA, still usable, yet still a bit high current draw but much better than 19 and 20mA draw of the original on-board circuit.
In conclusion, the on board LED has an acceptable brightness range from dim to slightly brighter with 100 to 150 ohm resistors resulting in 13 and 12mA current draw respectively.
The circuit is usable for tests but not simultaneous operations. A second LED circuit will be introduced for data that consumes a mere 1mA that can function simultaneously with all 20 boards.
Introducing Brain Replicants Modular Brain Pieces for Assembly
I worked up a rough sketch of the brain in schematic form and for the next several days it will be improved. Then work can move on to replicating it. The Brain Stem connected to the Brain Base connected to the Brain Span will be connected to Brain Replicants. Replicants will be constructed in groups of three and tested in the same configuration. A group of three represents a mulit-processor configuration ideal for testing. This technique was utilized with the TriCore Stamp Supercomputer.
When all six groups of three are built and tested, they will be assembled into the Brain Aggregate. The schematic worked on now is designed for wiring Replicants. There are at least two additional schematic rough sketches, one for the Brain Stem and one for the Brain Base. I'm thinking about creating a modular schematic that would be more manageable and expandable.
This source compares a computer to a human brain and discusses the similarities and differences. Interesting points include self repair, self maintenance, degradation, dedicated sections, growing memory capacity, electrical signals, upgrading and evolution, combining components, role in society and function/purpose.
Key interest points for the Brain project are self maintenance/repair and combining components. We talked about combining components earlier and recycling, as this will become a key factor in developing more thinking power per unit area.
It is easier to fix a computer - just get new parts. There are no new or used parts for the brain. However, some work is being done with transplantation of nerve cells for certain neurological disorders such as Parkinson's disease. Both a computer and a brain can get "sick" - a computer can get a "virus" and there are many diseases that affect the brain. The brain has "built-in back up systems" in some cases. If one pathway in the brain is damaged, there is often another pathway that will take over this function of the damaged pathway.
Reset Install Examination of method to install reset circuit
The PPPB does not have a standard full size island solder point for a dedicated reset. However, the place to catch reset is at the Prop Plug location. Another set of islands are at the USB2SER position. To located reset (RES), plug in the Prop Plug, logo face up, and read the markers.
Two places exist to solder a reset line at the
PropClip holes or the USB2SER holes.
Starting closest to the barrel power jack, read RX,
TX, RES, and VSS. The VSS/RES pair make a
complete reset circuit that can be actuated by a
push button switch or by a grounding pin.
Brain Span Troubleshooter
Repairs made the next day
After a flawless day of Brain Span op,
the next day board-one had intermittent
failures and could not maintain the LED
cycle. It was the most peculiar failure as
one moment it worked and thext 5 minutes
it would not. I feared the worst, however, the
anomaly was traced to a bad yellow data
jumper, leading from the breadboard
junction with trace-back to the on-board
LED. The jumper was replaced and
the Brain Span is now up and running
flawlessly. After a thousand cycles of
testing, the next Brain phase will begin.
Brain Span Animation Showing cycles of two LEDs per board
There's a green and red blinking light on each
PPPB. The program cycle was slowed to settle
the ammeter reading. Each board draws about
4mA, green LEDs draw about 19mA, red LEDs
draw 1mA. Total load measured is 54mA.
The first Brain Span working with three boards
and blinking six data LEDs
Increasing Brain Span Power Reliability
Discovering settings to increase reliability
In driving three PPPBs and two LEDs per board
with a load of 52mA, board one went out. Why?
The anomaly was simply traced to a bench power
supply setting. While calibrated to 3.3 Vin, another
calibration is required for current delivery. Use
coarse and fine calibration settings to deliver
enough current when using external power supplies.
Although wiring on breadboards is greatly simplified by using pre-made wire jumpers (see photo), their use must be handled with caution. There is approximately a 2 to 5% failure rate.
This jumper failed on Data LED
conversion circuit on board one the next day
Brain Span Serial Communications
Bspan_send.spin, Bspan_receive.spin
Prop to Prop Bspan serial communications is now working
at its most simple level V1.0. This is one wire serial communications
at 9600 Baud with eight stop bits and positive polarity with a BUS
interface. Each Propeller can talk or receive. The first Propeller is
a designated Master. In the test block, the remaining two PPPBs
are slaves. Both slaves are currently listeners while the Master is
the talker. Serial transmission is accurate and stable over a million
bit test. The code pair is a talk/listen configuration.
Showing the PST on COM52 with Propeller #1 as a talker and #2 as a listener
New Brain Exoskeleton Structure A different kind of Skyscraper
The Brain is a towering exoskeleton
with parts and circuits on the outside
In a single evening the Brain Blob suddenly and significantly grew upwards. Most noteworthy is how it grew. Instead of a one-on-one board-on-top stack, the structure is a tri-layer Exoskeleton with obverse back to back appendage AND a front to back high rise. Assembled are two rows of six meshed together and another six waiting for wiring and then connection. Three rows of concatenated six is eighteen boards with one at the top makes 19. Board #20 is obviously part of the Brain Stem and it will have various try-out locations for positioning. The interesting thing about the new skyscraper is that the parts and components, as well as Propleller chips, are connected to the outside of the structure and are extremely easy to access for wiring and rewiring.
Software with BS2 Functions For use with the Brain Blob
The BS2 Object Library by Martin Hebel http://obex.parallax.com/objects/30/
General PBASIC functionality library, written in Spin, that mimics and extends many popular BS2 functions: COUNT, DEBUG, DEBUGIN, FREQOUT, PAUSE, PULSOUT, PULSIN, PWM, RCTIME, SEROUT, SERIN, SHIFTOUT, SHIFTIN.
Version 1.5.0 adds methods for HIGH/LOW/IN, and continuous methods for FREQOUT, PWM and COUNT. It also adds EEPROM access for code and high memory access using READ and WRITE methods.
Don't forget to start -Needed for timing: BS2.Start(31,30)
BS2 Commands Simplified by Microcontrolled http://obex.parallax.com/objects/589/
This object is perfect for Propeller beginners coming from a BS2 background! It is not complicated and has full instructions for operation in the comments. You can get a "Hello World" program running in no-time! This object needs the FullDuplexSerial object, which is also available on the OBEX. You will also need the Parallax Serial Terminal, which should be installed on your computer if you have Propeller Tool 1.2.6 or up. This object will give you the following commands:
Pause(time)
High(pin)
Low(pin)
Input(pin)
Sleep(period)
Count(pin,duration,variable)
Debug(str)
Random
Toggle(pin)
Instructions on how to integrate them into your program are in the comments at the header of the program. If you have any questions or suggestions for new commands, contact me at microcontrolled@gmail.com
Version 1.0.1 : Added extra helpful instructions in the comment area.
Multi Level Stack MLS Brain Board Configuration
Formulating a final form
Brain boards are configured in a form try-out. Wiring is partially completed. Fifteen boards
hold 120 processors for programming.
The Brain Blob has evolved to this point. As you can see this is an ongoing process of assembling the boards and doing the wiring. As seen in the photo, this is a sideways orientation trial for 15 boards.
Some things learned
The breadboards will need a better fastening to the PBBBs so the tape rolls will be removed and the boards will be attached with their original sticky backs.
Alternating left-right positions of the PBBs will more balance the boards and distribute the weight of the bread-boards.
Overlapping boards at the spacer positions create a gradual narrowing effect which can contribute to greater balance in the proper orientation.
Solder points on the back of boards can contact the front of adjacent boards and can be covered with a small piece of dialectic cardboard.
For the inside row of boards, components must have short leads or can bend closer to the board.
The use of nylon spacers and hardware is essential
to keeping the overall weight to a minimum for portable
robotics.
In spacers alone, there are 14x4=56 holding the boards
together. 28 nuts attach the boards on the outer sections
to the spacers. The combined spacer and nuts weight
is negligible and not a weight contributing factor.
After numerous circuit tests, some values were established
for components. Construction is now centered on two resistor
values for both 5VDC and 3.3VDC circuits. 2k2 is established
for single wire bus and pin protection while 4k7 is useful
for LED dropping resistors on both 5 and 3.3-volt circuits.
As discovered earlier, use of a correct resistor-LED pair
can reduce current consumed to a mere 1mA.
Open Season on Serial Objects Serial communications sources abound
Consult this list of Serial Objects for SPIN Programming, which includes
sources found at the Parallax OBEX and postings on the Parallax Forum,
for developing software with the Brain Blob.
Brain Exoskeleton Redesigned
New design improvements
A major redesign improves the entire brain system.
There's no longer a row of side-by-side boards inside
the two board rows as this limits full access to wiring and
viewing. In the new arrangement, there are three open
sides forming a rectangular box which is open on one side.
Photos will be taken at the next photo session.
Some new feature of this design are as follows:
Vertical or horizontal orientation
Complete access to wiring
Instantaneous visual inspection
Full exposure of LEDs
Fast rewiring
Easy modifications
More simplified testing
More efficient maintenance
Attractive WYSIWYG appearance
Simple assembly
Assembly
Assembly is simplified with spacers and angle brackets
and supporting hardware (bolts & nuts). Configs have
three rows of six boards (with one prop to a board)
arranged as stated, and held together with two rows
of spacers. The "back" is attached with angle brackets.
One board completes the "top" in the vertical
orientation or a side in the horizontal. Any board
location can become the TV/VGA/mouse/keyboard
hookup. This is super convenient.
Remaining Decisions
With a total of 21 boards, it is not decided where the
extra board will reside. Three sides of 6 boards and one
on the top plus one on the bottom make a total of 20
boards. Contemplatively the extra board could orient
sticking out in the front or back, orthogonal to the
assemblage. Unless someone has a better idea?
In the parts box I have several LCDs and need to select one most suited for the brain. Some
considerations are:
Size (for mounting on the Exoskeleton & easy viewing)
Weight (important for portability)
Function (will interface to serial Bus same as a prop)
Power draw (must operate on batteries)
The larger display with four lines could represent more data and the
keyboard could prove worthy for some interesting brain functions.
The choice is between the following LCDs from Parallax. Which one
would you choose?
#27977 backlit or #27976 non-backlit LCDs
Parallax quote: This display provides basic text wrapping so that your text looks right. You have full control over all of its advanced LCD features, allowing you to move the cursor anywhere on the display with a single instruction and turn the display on and off in any configuration. It directly supports ASCII Dec 32-127, the same visible characters as the BASIC Stamp Editor's Debug Terminal. In addition, you may define up to eight of your own custom characters to display anywhere on the LCD. This display and many applications and programming examples are featured in our Smart Sensors and Applications Parts & Text Kit (#28029). This device can be connected to a PC serial port using a MAX232 line driver. The circuit isn't supported by Parallax, but it's possible to make this connection with a few dollars of parts.
Features:
Clear 2x16 character display
Turn backlighting on or off with a single command
Directly supports ASCII DEC characters 32-127
Eight user-definable custom characters
Move the cursor anywhere on the display with a single command
Baud mode selector and adjustable contrast on the back of the display
Key Specifications:
Power requirements: +5 VDC, 20 mA (light off), 80 mA (light on)
Selectable asynchronous serial baud rates: 2400, 9600, 19200
Dimensions: Approx. 1.5 x 3.15 in (38 x 80 mm) NOTE: Board and LCD size and style may vary
Operating temp range: -4 to +158 °F (-20 to +70°C)
#30058 4x20 Serial LCD with keypad interface
Parallax Quote: Do you need more general purpose outputs, a keypad interface (up to a 5x5 Keypad), and a cool screen? If you answered yes to more than one of these items, this is the LCD for you! Below is a description with information relating to the size and functionality of this new device. The Matrix Orbital part number is LK204-25-WB. This version is pre-modified for BASIC Stamp module-compatibility.
Features:
20x4 Display
Keypad Interface: 25 (5x5)
6 General Purpose Output
Horizontal & Vertical bar graph modes
Large Digits
Automatic Line Wrapping & Scrolling
Appearance: Inverse Blue with White Backlight
RS232 mode (Compatible with TTL levels) : 1200bps to 19.2 Kbps
I2C mode: Serial transfers of up to 100 Kbps & connect up to 16 displays
Fully Buffered - no delays in transmission
Key Specifications:
Power Requirements: 5 VDC @ 40 mA (Backlight Off) / 110 mA (Backlight On)
Communication: Asynchronous serial (TTL) or I2C
Dimensions: 3.86 x 2.36 x 1.20 in (98 x 60 x 30.63 mm)
Operating Temperature: +32 to +122 °F (0 to +50 °C)
Comments
A 100 ohm add-in resistor produces an acceptable LED brightness. This is perhaps the minimal brightness. Current draw is from 4mA to 13mA, still quite high.
A 150 ohm resistor produced a dim LED at 12mA, still usable, yet still a bit high current draw but much better than 19 and 20mA draw of the original on-board circuit.
In conclusion, the on board LED has an acceptable brightness range from dim to slightly brighter with 100 to 150 ohm resistors resulting in 13 and 12mA current draw respectively.
The circuit is usable for tests but not simultaneous operations. A second LED circuit will be introduced for data that consumes a mere 1mA that can function simultaneously with all 20 boards.
Modular Brain Pieces for Assembly
I worked up a rough sketch of the brain in schematic form and for the next several days it will be improved. Then work can move on to replicating it. The Brain Stem connected to the Brain Base connected to the Brain Span will be connected to Brain Replicants. Replicants will be constructed in groups of three and tested in the same configuration. A group of three represents a mulit-processor configuration ideal for testing. This technique was utilized with the TriCore Stamp Supercomputer.
When all six groups of three are built and tested, they will be assembled into the Brain Aggregate. The schematic worked on now is designed for wiring Replicants. There are at least two additional schematic rough sketches, one for the Brain Stem and one for the Brain Base. I'm thinking about creating a modular schematic that would be more manageable and expandable.
Key interest points for the Brain project are self maintenance/repair and combining components. We talked about combining components earlier and recycling, as this will become a key factor in developing more thinking power per unit area.
The brain vs computer at a simple level.
It is easier to fix a computer - just get new parts. There are no new or used parts for the brain. However, some work is being done with transplantation of nerve cells for certain neurological disorders such as Parkinson's disease. Both a computer and a brain can get "sick" - a computer can get a "virus" and there are many diseases that affect the brain. The brain has "built-in back up systems" in some cases. If one pathway in the brain is damaged, there is often another pathway that will take over this function of the damaged pathway.
http://hiddentalents.org/brain/jpg/b-right.jpg
http://hiddentalents.org/brain/113-left.html#body
http://hiddentalents.org/brain/113-right.html
http://www.wizardofads.com.au/brain-map-brocas-area/
http://www.wizardofads.com.au/storage/BrainMap.jpg?__SQUARESPACE_CACHEVERSION=1231039829503
http://www.flickr.com/photos/davegray/2812087554/in/photostream/
P24 - DATA LED A
P25 - DATA LED B
P26 - RESET
P27 - BUS
P28 - EEPROM SDA
P29 - EEPROM SCL
P30 - TX
P31 - RX
Vdd - 3.3 VDC
Vss - GROUND
the current (in flux) brain concept
Modular Hardware
Brain Stem
Brain Base
Brain Span
Brain Replicants
Brain Aggregate
Software
Testing
Loading
Enumeration
Data LEDs
BUS Rx Tx
Computational
Foundation Process
Prepare
Load
Reset
Talk
Listen
Think
Input
Output
State
Demo
Exampling
Enhance
Algorithm
Distribute
Announce
Evolve
Modify
Delete
Wait
Memorize (short term)
Memorize (long term)
Matrix
Time
Emote
Sleep
Birth
Training
Learning
Evolving
Thinking
Energy Process
Motivation
Behavior
Attention Span
Distraction
Needs, Wants, Desires
Planning
Organizing
Sorting
Relational Inferences
Rational Thought
Recognition
Insight
Logic
Philosophical
Mathematical
Musical
Knowledge Data Base
Language
Sense
Touch
Nap
Sight & Vision
Directional Listening
Recording
Mental Images
Motion
Speaking
Memorizing
Forgetting
Regulation
Activation
Timing
Associative Process
Context Determinator
Self Aware
Originality
Conversation
Examination of method to install reset circuit
The PPPB does not have a standard full size island solder point for a dedicated reset. However, the place to catch reset is at the Prop Plug location. Another set of islands are at the USB2SER position. To located reset (RES), plug in the Prop Plug, logo face up, and read the markers.
Two places exist to solder a reset line at the
PropClip holes or the USB2SER holes.
Starting closest to the barrel power jack, read RX,
TX, RES, and VSS. The VSS/RES pair make a
complete reset circuit that can be actuated by a
push button switch or by a grounding pin.
Yellow lead from LED resistor to Propeller pin
The yellow wire is long enough to reach
any of the available pins on the plug
socket array.
...
LEDs indicate functioning
This is the "where's Waldo" of
the PPPB. Find two LEDs on each
board, one green and one red.
Repairs made the next day
After a flawless day of Brain Span op,
the next day board-one had intermittent
failures and could not maintain the LED
cycle. It was the most peculiar failure as
one moment it worked and thext 5 minutes
it would not. I feared the worst, however, the
anomaly was traced to a bad yellow data
jumper, leading from the breadboard
junction with trace-back to the on-board
LED. The jumper was replaced and
the Brain Span is now up and running
flawlessly. After a thousand cycles of
testing, the next Brain phase will begin.
Showing cycles of two LEDs per board
There's a green and red blinking light on each
PPPB. The program cycle was slowed to settle
the ammeter reading. Each board draws about
4mA, green LEDs draw about 19mA, red LEDs
draw 1mA. Total load measured is 54mA.
The first Brain Span working with three boards
and blinking six data LEDs
Discovering settings to increase reliability
In driving three PPPBs and two LEDs per board
with a load of 52mA, board one went out. Why?
The anomaly was simply traced to a bench power
supply setting. While calibrated to 3.3 Vin, another
calibration is required for current delivery. Use
coarse and fine calibration settings to deliver
enough current when using external power supplies.
Simplified wiring with jumpers
Although wiring on breadboards is greatly simplified by using pre-made wire jumpers (see photo), their use must be handled with caution. There is approximately a 2 to 5% failure rate.
This jumper failed on Data LED
conversion circuit on board one the next day
Kept in dust-free containers
It's definitely NOT a NASA clean room
but the next best thing is a Chinese KFC
special food container to keep out dust.
Brain Span Boards kept in recycled dust free
containers - opened here for building the next
Brain Span Module
Simple software test for Brain Span
Take your Brain Blob's Brain Span for a spin
using this modified software to actuate both
data LEDs in a slower cycle.
For testing data lights connections, power
draw, pins, and CPU program operations.
This code also tests the cycle of all three boards
in unison to observe the degree of synchronization.
Bspan_send.spin, Bspan_receive.spin
Prop to Prop Bspan serial communications is now working
at its most simple level V1.0. This is one wire serial communications
at 9600 Baud with eight stop bits and positive polarity with a BUS
interface. Each Propeller can talk or receive. The first Propeller is
a designated Master. In the test block, the remaining two PPPBs
are slaves. Both slaves are currently listeners while the Master is
the talker. Serial transmission is accurate and stable over a million
bit test. The code pair is a talk/listen configuration.
Showing the PST on COM52 with Propeller #1 as a talker and #2 as a listener
A different kind of Skyscraper
The Brain is a towering exoskeleton
with parts and circuits on the outside
In a single evening the Brain Blob suddenly and significantly grew upwards. Most noteworthy is how it grew. Instead of a one-on-one board-on-top stack, the structure is a tri-layer Exoskeleton with obverse back to back appendage AND a front to back high rise. Assembled are two rows of six meshed together and another six waiting for wiring and then connection. Three rows of concatenated six is eighteen boards with one at the top makes 19. Board #20 is obviously part of the Brain Stem and it will have various try-out locations for positioning. The interesting thing about the new skyscraper is that the parts and components, as well as Propleller chips, are connected to the outside of the structure and are extremely easy to access for wiring and rewiring.
Some features include:
For use with the Brain Blob
The BS2 Object Library by Martin Hebel
http://obex.parallax.com/objects/30/
General PBASIC functionality library, written in Spin, that mimics and extends many popular BS2 functions: COUNT, DEBUG, DEBUGIN, FREQOUT, PAUSE, PULSOUT, PULSIN, PWM, RCTIME, SEROUT, SERIN, SHIFTOUT, SHIFTIN.
Version 1.5.0 adds methods for HIGH/LOW/IN, and continuous methods for FREQOUT, PWM and COUNT. It also adds EEPROM access for code and high memory access using READ and WRITE methods.
Don't forget to start -Needed for timing: BS2.Start(31,30)
PAUSE by Peter Quello
http://obex.parallax.com/objects/34/
This is similar to BS2_Functions' Pause routine.
BS2 Commands Simplified by Microcontrolled
http://obex.parallax.com/objects/589/
This object is perfect for Propeller beginners coming from a BS2 background! It is not complicated and has full instructions for operation in the comments. You can get a "Hello World" program running in no-time! This object needs the FullDuplexSerial object, which is also available on the OBEX. You will also need the Parallax Serial Terminal, which should be installed on your computer if you have Propeller Tool 1.2.6 or up. This object will give you the following commands:
Pause(time)
High(pin)
Low(pin)
Input(pin)
Sleep(period)
Count(pin,duration,variable)
Debug(str)
Random
Toggle(pin)
Instructions on how to integrate them into your program are in the comments at the header of the program. If you have any questions or suggestions for new commands, contact me at microcontrolled@gmail.com
Version 1.0.1 : Added extra helpful instructions in the comment area.
Formulating a final form
Brain boards are configured in a form try-out.
Wiring is partially completed. Fifteen boards
hold 120 processors for programming.
The Brain Blob has evolved to this point. As you can see this is an ongoing process of assembling the boards and doing the wiring. As seen in the photo, this is a sideways orientation trial for 15 boards.
Some things learned
The breadboards will need a better fastening to the PBBBs so the tape rolls will be removed and the boards will be attached with their original sticky backs.
Alternating left-right positions of the PBBs will more balance the boards and distribute the weight of the bread-boards.
Overlapping boards at the spacer positions create a gradual narrowing effect which can contribute to greater balance in the proper orientation.
Solder points on the back of boards can contact the front of adjacent boards and can be covered with a small piece of dialectic cardboard.
For the inside row of boards, components must have short leads or can bend closer to the board.
Keeping minimal weight
The use of nylon spacers and hardware is essential
to keeping the overall weight to a minimum for portable
robotics.
In spacers alone, there are 14x4=56 holding the boards
together. 28 nuts attach the boards on the outer sections
to the spacers. The combined spacer and nuts weight
is negligible and not a weight contributing factor.
Establishing resistor values
After numerous circuit tests, some values were established
for components. Construction is now centered on two resistor
values for both 5VDC and 3.3VDC circuits. 2k2 is established
for single wire bus and pin protection while 4k7 is useful
for LED dropping resistors on both 5 and 3.3-volt circuits.
As discovered earlier, use of a correct resistor-LED pair
can reduce current consumed to a mere 1mA.
Color code chart from www.bkbelectronics.com
Serial communications sources abound
Consult this list of Serial Objects for SPIN Programming, which includes
sources found at the Parallax OBEX and postings on the Parallax Forum,
for developing software with the Brain Blob.
http://forums.parallax.com/entry.php?91-2nd-Blog-More-about-the-Brain-Project
New design improvements
A major redesign improves the entire brain system.
There's no longer a row of side-by-side boards inside
the two board rows as this limits full access to wiring and
viewing. In the new arrangement, there are three open
sides forming a rectangular box which is open on one side.
Photos will be taken at the next photo session.
Some new feature of this design are as follows:
- Vertical or horizontal orientation
- Complete access to wiring
- Instantaneous visual inspection
- Full exposure of LEDs
- Fast rewiring
- Easy modifications
- More simplified testing
- More efficient maintenance
- Attractive WYSIWYG appearance
- Simple assembly
AssemblyAssembly is simplified with spacers and angle brackets
and supporting hardware (bolts & nuts). Configs have
three rows of six boards (with one prop to a board)
arranged as stated, and held together with two rows
of spacers. The "back" is attached with angle brackets.
One board completes the "top" in the vertical
orientation or a side in the horizontal. Any board
location can become the TV/VGA/mouse/keyboard
hookup. This is super convenient.
Remaining Decisions
With a total of 21 boards, it is not decided where the
extra board will reside. Three sides of 6 boards and one
on the top plus one on the bottom make a total of 20
boards. Contemplatively the extra board could orient
sticking out in the front or back, orthogonal to the
assemblage. Unless someone has a better idea?
Eavesdropping on the Brain's thinking
In the parts box I have several LCDs and need to select one most suited for the brain. Some
considerations are:
- Size (for mounting on the Exoskeleton & easy viewing)
- Weight (important for portability)
- Function (will interface to serial Bus same as a prop)
- Power draw (must operate on batteries)
The larger display with four lines could represent more data and thekeyboard could prove worthy for some interesting brain functions.
The choice is between the following LCDs from Parallax. Which one
would you choose?
#27977 backlit or #27976 non-backlit LCDs
Parallax quote: This display provides basic text wrapping so that your text looks right. You have full control over all of its advanced LCD features, allowing you to move the cursor anywhere on the display with a single instruction and turn the display on and off in any configuration. It directly supports ASCII Dec 32-127, the same visible characters as the BASIC Stamp Editor's Debug Terminal. In addition, you may define up to eight of your own custom characters to display anywhere on the LCD. This display and many applications and programming examples are featured in our Smart Sensors and Applications Parts & Text Kit (#28029). This device can be connected to a PC serial port using a MAX232 line driver. The circuit isn't supported by Parallax, but it's possible to make this connection with a few dollars of parts.
Features:
- Clear 2x16 character display
- Turn backlighting on or off with a single command
- Directly supports ASCII DEC characters 32-127
- Eight user-definable custom characters
- Move the cursor anywhere on the display with a single command
- Baud mode selector and adjustable contrast on the back of the display
Key Specifications:#30058 4x20 Serial LCD with keypad interface
Parallax Quote: Do you need more general purpose outputs, a keypad interface (up to a 5x5 Keypad), and a cool screen? If you answered yes to more than one of these items, this is the LCD for you! Below is a description with information relating to the size and functionality of this new device. The Matrix Orbital part number is LK204-25-WB. This version is pre-modified for BASIC Stamp module-compatibility.
Features:
- 20x4 Display
- Keypad Interface: 25 (5x5)
- 6 General Purpose Output
- Horizontal & Vertical bar graph modes
- Large Digits
- Automatic Line Wrapping & Scrolling
- Appearance: Inverse Blue with White Backlight
- RS232 mode (Compatible with TTL levels) : 1200bps to 19.2 Kbps
- I2C mode: Serial transfers of up to 100 Kbps & connect up to 16 displays
- Fully Buffered - no delays in transmission
Key Specifications:If you had a keyboard on your personal brain with 25 keys,
what functions would you assign to each key?
Here are some of my ideas: