Difference between revisions of "RGB Matrix Backpack"
From Hackstrich
(Issues with rev. 1 found.) |
(Doh, need an LDO not an LM317.) |
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* Silkscreen on inter-board connectors is incorrect on some | * Silkscreen on inter-board connectors is incorrect on some | ||
* Constant current regulator not implemented properly, output should be on the far side of the current sense resistor, not the near side | * Constant current regulator not implemented properly, output should be on the far side of the current sense resistor, not the near side | ||
| + | * Constant current regulator uses an LM317 (3V dropout) which won't work for the green/blue LEDs because they need 3.3v max | ||
[[Category:Current Projects]] | [[Category:Current Projects]] | ||
[[Category:Status/Waiting for Parts]] | [[Category:Status/Waiting for Parts]] | ||
Revision as of 00:09, 4 January 2011
The RGB Matrix Backpack will be a small controller board to attach to 8x8 RGB LED matrices. It will accept input via SPI or I2C and control the display.
Project Status
Revision 1 board assembled, troubleshooting and writing code now.
Rough Notes
- Going to use the PIC18F65K22 as it will drive all the pins needed directly (no muxes or anything) and is <$5 in single qty. Cheaper than using multiplexers and more flexible this way.
- Also I haven't used PICs in any projects in ~5 years, so I want to try them out again :)
- Cathode/low side (columns) will be N-channel MOSFETs.
- Which is nice because there are 24 columns to drive, but only 8 rows. Cheaper components on the columns is handy.
- Anode/high side (rows) should be a constant current source with P-channel MOSFETs.
- Being able to plug them together in a 2D matrix would be awesome
- They plug into a 1D matrix natively, and there's a cable interface to link multiple 1D rows together into a 2D display
Revision 1 Notes
- Silkscreen on inter-board connectors is incorrect on some
- Constant current regulator not implemented properly, output should be on the far side of the current sense resistor, not the near side
- Constant current regulator uses an LM317 (3V dropout) which won't work for the green/blue LEDs because they need 3.3v max
