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Topic: Pinball (Read 2813 times) previous topic - next topic

willhew

Yes, but will the arduino run a DMD like that?

GoForSmoke

The Arduino chip can run the chips that can, even if it's chips on a shield on an Arduino.

SPI bus is (clock / 8) bits per second, IIRC. That takes 3 pins plus 1 pin for every control line. Some chips like shift registers, one control line does a whole line of them.
Nick Gammon on multitasking Arduinos:
1) http://gammon.com.au/blink
2) http://gammon.com.au/serial
3) http://gammon.com.au/interrupts

willhew

Hi, I'm still going for the option of handmaking the DMD, how many shift registers can I use before the signal degrades, I would use rows of 4 down 128 across or vice versa (32 registers down, 16 across) will the signal degrade? I want to use a seperate arduino for the display, what is the smallest I can use. I would use a serial output from the main CPU to the DMD CPU which would use built in commands to detect, eg. It detects a three so it uses the assigned bitmap.

Will this work,

Will

CrossRoads

I would use an octal register wired like a shift register,
http://arduino.cc/forum/index.php/topic,97488.15.html
http://arduino.cc/forum/index.php/topic,103072.0.html
use a part like sn74ac574 so you have good drive current, 24mA, not the measly 4-6mA of an HC595. That will drive the rows of anodes.
May need a buffer on the clock line, have to check the  '574 input current requirements.
Then for the columns, shift registers driving MOSFETs to sink all the cathode current.

Size may be driven by the SRAM you need to hold the data array that you be shifting out. 
Pinwise, need enough IO for Rx/Tx, SCK-MISO-MOSI, SS for columns and SS for rows.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

willhew

Hi,

Im not familiar with octal registers, are they larger versions of shift registers. I plan to use the chipKIT max32 to run the main machine, switches, bumpers etc. but a seperate controller for the DMD, I would prefer to use the chipKIT to run it as well, but if it simplifies it I would rather seperate. Will it be simpler?

Will

dxw00d


Hi all, I am building a Jurassic Park 3 pinball. Is arduino a suitable thing to use for this? It is a fullsize pinball machine.

Thanks,

Will



I plan to use the chipKIT max32 to run the main machine, switches, bumpers etc.


Twenty posts before you tell us you aren't using an Arduino.

willhew

They are extremely similar, and I am using another processor for the DMD which I need the most help for, the processor for the screen is an arduino

GoForSmoke


Hi, I'm still going for the option of handmaking the DMD, how many shift registers can I use before the signal degrades, I would use rows of 4 down 128 across or vice versa (32 registers down, 16 across) will the signal degrade? I want to use a seperate arduino for the display, what is the smallest I can use. I would use a serial output from the main CPU to the DMD CPU which would use built in commands to detect, eg. It detects a three so it uses the assigned bitmap.

Will this work,

Will


You're running digital signals and with serial shift registers each one can serve to connect the next one, the signal re-originates at each chip. That's with 4 Arduino pins and lots of data out through SPI to run the whole show.
Power distro will be a concern and that will be different if you multiplex (limited leds can be ON at the same time) vs one-register-pin-to-led (all leds can be ON at once).  Multiplexing cuts the number of shift registers required significantly. Charlieplexing can cut the number even more, but the wiring will be a maze in itself. All of those can be run from serial data on a daisy-chained SPI bus at cost of 4 MCU pins.

Nick Gammon on multitasking Arduinos:
1) http://gammon.com.au/blink
2) http://gammon.com.au/serial
3) http://gammon.com.au/interrupts

willhew

So I am still unsure, can someone tell me will it be easier to wire a 6 pin pre made DMD or to make my own?

Will

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