Propeller for universities
John Abshier
Posts: 1,116
At the Propeller Expo Paul Baker talked about getting the Propeller into universities.· First, I do not know how cost sensitive universites are.· I expect that MIT/Stanford are less so than small state schools with a direction in their name.· The Professional Development Board looks nice for general electronics/microcontroller uses but is too big for many robot applications.· How about a Propeller board inspired by the MIT Handyboard?· The attached file (Collegeboards.rtf) has some specifications on several boards.·
Here are my thoughts on a Propeller Handyboard (the gold plated version)
Power:· 7.2 to 13 volts· This would work with various battery packs to include 12volt lead acid
Motor controllers:· 4 1·amp required, 2 amp desired.· Screw terminals to connect motors.
I/O connectors:· Polarized.·
User I/O board:· Separate board to allow flexibility in mounting.· It has an LCD, some buttons (up, down, left, right, select/enter, exit), and some different colored LEDs for indication when the LCD is hard to read
Wireless communications:· Optional.· Provide a connection (RX,TX, Pwr, Gnd) for a Zigbee board
Analog input:· 5 volts, 10-12 bits,· pullups are selected by jumpers
I/O expander chip:· 8 high current outputs (darlington) and 8 general I/O.· This could be reduced to 2 transitor outputs and 6 general I/O.· The high power outputs are for driving relays or solenoids.
EEPROM: 64 kB to allow for data logging
Attached PropHandyboardPins.txt file·accounts for pin usage.· I know that an advantage of I2C is that many things can use the same bus.· For this design, I would prefer that each I2C device have its own bus to lessen the chance of two cogs trying to use the bus at the same time.· But perhaps this is a teaching opportunity.· I did not use an inverter to use one pin to drive the motor A&B pins to allow for braking.· Some motor drivers require fewer pins.· The ADC might be able to combine the data out/in pins.· One item that I don't have in the design is a buzzer.· It could use a freed up pin or two.· Additional uses for freed up pin could be RTS/Sleep for Zigbee board.
Since this will be used by students, most of them not EEs, design for robustness.
John Abshier
Post Edited (John Abshier) : 9/4/2008 10:35:13 PM GMT
Here are my thoughts on a Propeller Handyboard (the gold plated version)
Power:· 7.2 to 13 volts· This would work with various battery packs to include 12volt lead acid
Motor controllers:· 4 1·amp required, 2 amp desired.· Screw terminals to connect motors.
I/O connectors:· Polarized.·
User I/O board:· Separate board to allow flexibility in mounting.· It has an LCD, some buttons (up, down, left, right, select/enter, exit), and some different colored LEDs for indication when the LCD is hard to read
Wireless communications:· Optional.· Provide a connection (RX,TX, Pwr, Gnd) for a Zigbee board
Analog input:· 5 volts, 10-12 bits,· pullups are selected by jumpers
I/O expander chip:· 8 high current outputs (darlington) and 8 general I/O.· This could be reduced to 2 transitor outputs and 6 general I/O.· The high power outputs are for driving relays or solenoids.
EEPROM: 64 kB to allow for data logging
Attached PropHandyboardPins.txt file·accounts for pin usage.· I know that an advantage of I2C is that many things can use the same bus.· For this design, I would prefer that each I2C device have its own bus to lessen the chance of two cogs trying to use the bus at the same time.· But perhaps this is a teaching opportunity.· I did not use an inverter to use one pin to drive the motor A&B pins to allow for braking.· Some motor drivers require fewer pins.· The ADC might be able to combine the data out/in pins.· One item that I don't have in the design is a buzzer.· It could use a freed up pin or two.· Additional uses for freed up pin could be RTS/Sleep for Zigbee board.
Since this will be used by students, most of them not EEs, design for robustness.
John Abshier
Post Edited (John Abshier) : 9/4/2008 10:35:13 PM GMT
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http://forums.parallax.com/showthread.php?p=650217
meow, i have my own topic now? (sorta)
Hello John,
I am very familiar with the HandyBoard and have used it in several projects. If you read SERVO you may have seen an article I wrote that covered a few issues with the original HandyBoard and some ways to correct them. It would definitely be possible to make a similar board based on the Propeller chip. That is something I wouldn't mind working on as it would help with some other projects as well.
I think that the propeller could run Interactive-C and in that case it could use the existing tools and code. It would require writing some code for the Propeller. Then it could act as a Handyboard to use Interactive-C or could be programmed directly in SPIN or assembly.
Robert