Synopsis of the Relay board thread from the Sandbox
kwinn
Posts: 8,697
Reserved for the latest version of the hardware and software.
Post Edited (kwinn) : 7/25/2009 3:39:36 AM GMT
Post Edited (kwinn) : 7/25/2009 3:39:36 AM GMT
Comments
This is the latest revision of the hardware and software. No further hardware changes are expected. The software has been rewritten in PASM for speed but it is not finished. Here are the specs so far.
The time clock is accurate to 1mS.
The master board can select up to 16 slaves.
Each 56 bit slave takes 3mS to update at the current data rate of approximately 177Kb/S, so all 16 slaves can be updated in 48mS. The data rate can be reduced to drive long lines.
Post Edited (kwinn) : 7/24/2009 12:04:55 AM GMT
HARDWARE
The master would be a prop with either a good sized backup battery or a battery backed real time clock.
Peripherals (slaves) would be either simple shift registers ('595 style) or props (or possibly other I2C chips) using I2C or async serial protocol.
SOFTWARE
A simple interpreter that will execute commands:
> at specified times/time intervals (minutes, hours, days, weeks)
> when specific conditions are met
I have not decided if the commands should be in the eeprom or read from an sd card. It seems to me that there would not be so many commands in the list that an sd card is required, but I am open to suggestions.
Post Edited (kwinn) : 7/25/2009 8:14:34 PM GMT
I will post the master later today.
as mentioned i would use more then 1 via on the firing traces
straiten up the firing traces and avoid 90 bends
why do you have multiple voltage regulators? you should not paralel regulators like that
i do not see any caps before or after the regulator which are needed(100uF)
for safety i would recomend having a pull up resister right by the relay on the active relay coil(you are using low side firing) you can drop these traces to 12mil width
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Still needs Status LED's and copper pour.
Also looks like I need to add some pullup and pull down resistors.