I finished up on the changes and tweaks I wanted to make to the design, new schematic below. I think I have found a US based PCB house (in Nor Cal, no less!) that can do a run for not much more that what I would pay for the China based house I used last time. I should have the boards in less than 2 weeks as opposed to close to 4 weeks. Since I just finished it up today, and it’s Friday, I’ll wait till Monday to submit the design, giving me 2 days to look it over for any problems.
Few things I addressed in this version:
- Rotated the board on the shield so the inputs are on the same side as the Arduino USB port.
- Fixed 3 wiring errors.
- Added headers for attaching an LCD display with contrast potentiometer and optional dropping resistor for LED back-light. This will use 2, 6 pin jumpers to connect to the LCD.
- Corrected some of the cap and resistor solder pads, should be easier to solder.
- Fixed silkscreen errors on shield headers.
- Added optional 7805 regulator and 2.1mm power jack for running standalone (no USB power). 7805 WILL need heatsink as it’s dissipating around 2W, almost twice what the board, LCD and Arduino uses since it’s dropping 14V (from the back of the TS-520) down to 5V.
I looked at using a triple gang RCA jack, but couldn’t find one with an Eagle footprint, so I am sticking with the single jacks from Sparkfun for now. There is too much risk designing the footprint off the datasheet, part unseen.
New schematic. Only difference from the one below should be the addition of the 7805 and supporting components.