Can you please double check my wiring? Also, can you please advise me on resistor size?
COM PANEL (com.png)
Components:
1 x Arduino Mega
12 x TIP122
12 x LED Lights (12V)
12 x Resistors (??? what would be a good size???)
1 x 12Volt Power Source
9 x Push Button Switches
1 x Three Way Toggle Switch
NAV PANEL
1 x Arduino Mega
1 x 12Volt Power Source
2 x TIP122
2 x LED Lights (12V)
2 x Resistors (??? what would be a good size???)
6 x Push Button Switches
8 x Rotary Encoder Switches (B: out 1, C: GRND, A: out 2)
All the switch pins need (10k) pull down resistors to ground,
or... (easier) connect the switches between pin and ground, and use the internal pull up on the pin in pinMode().
Pin 0 and 1 are the RX/TX pins, and should not be used.
All transistors need their collector and emitter swapped (arrow goes to ground).
All LEDs need current limiting resistors (unless they are not just LEDs)
Post a link to the LEDs used.
Value of R1-14 depends on the collector current of the TIP122. Size can be small (0.25watt).
Base current should be about 1/250 of collector current for a TIP122.
Leo..
Thank you for all the responses and converting my diagram to white : )
So I cannot use analog 0 and 1 ports? I did not know that.
Here is a detailed list of the parts as it is designed. Click on the part to see where I bought it and specs.
Parts Used:
o TIP122
o Tactile Push Buttons
o Tactile Push Buttons with LED
o 3 Way Toggle Switch (SPDT) w/ Center Off - 4Amps @ 125VAC
o Rotary Encoder Switch: Rotary encoder: 6mm diameter "D" shaft with 18 indetent points with the Normally Open Spring Switch. Size: 0.50" sq. Mounts in a 0.30" hole in a panel. PCB Mount terminals
Questions:
All the switch pins need (10k) pull down resistors to ground.
All transistors need their collector and emitter swapped (arrow goes to ground).
Will do. This was my first design ever, so learning in progress : )
All LEDs need current limiting resistors (unless they are not just LEDs)
I think they have internal resistors. Specs shows as:
o Contact Resistance: less than 100ohms
o Insulation resistance: more than 100ohms
I cannot tell if those are for the switch or the LED.
Value of R1-14 depends on the collector current of the TIP122. Size can be small (0.25watt).
Base current should be about 1/250 of collector current for a TIP122.
ZiZiL55:
So I cannot use analog 0 and 1 ports? I did not know that.
Your schematic says pin 0 and 1, this are digital pins (the analog ones would be A0 and A1). These pins are used for uploading sketches (it's the Serial interface, these pins are also known as Tx and Rx).
They can be used of course, but you have to know what you're doing (depending on what's connected to them, you have to disconnect this before you can upload new sketches). These pins are best left alone until you run clean out of pins.
ZiZiL55:
You mean all the ports from the switches connect to digital and analog pins needs to be parallel to GRND?
Can I use this resistor?
I think the collector current of TIP122 is 5A...
Read post#1 again.
Up to you to connect the switches between pins and VCC or between pins and ground.
If you connect them between pin and ground, then you DON't need resistors.
If you connect them between pin and VCC (as in your diagram) then you do need resistors.
What matters is how much current the LEDs draw (you didn't post a link).
Note that a TIP122 can only switch ~1Amp without a heatsink (it gets hot above that).
Leo..
ZiZiL55:
Here is the link for the LEDs. They are embedded to the switches.
12volt/50mA seems to be the max rating for the switch contacts.
The LED is most likely a common LED without current limiting resistor.
If so, then you don't need the whole setup with TIP122 and 12volt supply.
Just connect the LEDs with suitable current limiting resistor straight to the Mega pins.
Test with a 1k CL resistor, and see if they are bright enough.
Leo..
