Btn/LED matrix vs direct configurations

[tago]

15 hours ago, latigid on said:

I haven't tried this with direct DOUT pins. I know for the WS2812-type LEDs "dimmed=1" will allow a CC to control the dimming level as defined in the LED event.

The manual states: "LEDs can now be dimmed with 16 brightness levels over the value range.". There aren't any additional parameters mentioned.

Like that it doesn't make too much sense for simple button/LED (on/off) combos where you want to set a fixed level. The map "trick" does it otherwise.

 

15 hours ago, latigid on said:

With a resistor, you're burning current*voltage as heat, so yes, switching the LED via PWM should be more efficient. Measure it yourself: set the multimeter to mA and connect it in series after the resistor. You'll need a higher value resistor to match the given dimmed value. 

Something else to keep in mind is you don't want a panel full of flashlights. The more LEDs on your panel, the lower brightness they should be (depending on how they're spread apart).

I tried to measure the current with my cheap multimeter, but failed. It always displayed zero. The fuse in the MM seemed ok but fell apart after removal. So i'll have get a new fuse and try again. But since it's PWM is it actually measurable that way?

Regarding flashlights, that why i'm doing all the testing. Maybe i should go with 10mA ones if 2mA is too dark and 20mA too bright.

[tago]

3 hours ago, gerald.wert said:

You can spend a lot of time routing traces in a cad program. If you etch your own PCB you also need to consider drill time. Limited drilling can be an advantage of strip or pad per hole board in a proto phase or a one off. You have a lot more freedom in part placement when making a board in cad. If you are planning more that one it is definitely worth cad time. +1 to also having more than one board, that will make your life a lot easier when you start to trouble shoot it in addition to the lower cost.

A single PCB of that dimension would be too risky for a beginner and the layout generally too specific to justify custom PCBs.

I think i'll stick with perfboards for now, although i have no idea how i should wire all those stuff together.

 

 

[latigid on]

10 hours ago, tago said:

I tried to measure the current with my cheap multimeter, but failed. It always displayed zero. The fuse in the MM seemed ok but fell apart after removal. So i'll have get a new fuse and try again. But since it's PWM is it actually measurable that way?

When measuring mA, never adjust the dial (e.g. voltage, resistance etc.) with the leads plugged into the mA measurement points. It's a low impedance measurement and you'll blow the fuse if connected across a voltage source. But if the LED still lit up, then the fuse was okay. Maybe you were set to Amps rather than milliAmps?

If the PWM speed is fast enough, you should get an average of the current draw. Some meters also have a max/averaging function.

[tago]

With my current design i'd need 4* DINX4 and 4* DOUTX4 when using direct connections between Btns/LEDs and SRs. For potentiometers i'd have an AINSER64. According to the docs double than that should be possible, but is such a large number of SRs going to negatively affect the MIOS32/Core32 performance?

 

On 20.3.2017 at 9:42 PM, latigid on said:

That's right Peter, encoders should be directly connected to 2* DIN pins. With button/LED matrices it can work and does save lots of pins and power, but the additional wiring might be suboptimal. For instance, anything other than a clean, square array will mean rows will be split, but the columns still need to be wired together. Of course, a way around this is to create multiple matrices based on smaller sections, even if not all positions are filled.

Best,
Andy

Is it possible to leave some LEDs out (eg per row) in a matrix?

Could you explain "multiple matrices based on smaller sections" any further?

 

I'm really not sure if matrix wiring is going to be too tricky/messy with frontpanel perfboards in the end. I've to make the (large) frontpanel pcb out of smaller ones. I assume for matrices i'll need some busses on these perfboards. But how will they fit in a space saving manner on a 2,54mm grid? Unfortunately i couldn't find photos of similar projects on the web to see how others approach all this.

 

 

 

[latigid on]

12 minutes ago, tago said:

With my current design i'd need 4* DINX4 and 4* DOUTX4 when using direct connections between Btns/LEDs and SRs. For potentiometers i'd have an AINSER64. According to the docs double than that should be possible, but is such a large number of SRs going to negatively affect the MIOS32/Core32 performance?

This is easy to test, just increase the number of shift registers defined in the NGC (max 32 I think), even if you have fewer in your chain. Now connect some hardware and see if you notice the latency. If you do, decrease the number of SRs until you're happy.

 

Quote

Is it possible to leave some LEDs out (eg per row) in a matrix?

Yes.

 

Quote

Could you explain "multiple matrices based on smaller sections" any further?

Instead of an 8*8 matrix, define two different ones, or however many you require based on the panel layout. You don't have to fill every position.

 

Quote

I'm really not sure if matrix wiring is going to be too tricky/messy with frontpanel perfboards in the end. I've to make the (large) frontpanel pcb out of smaller ones. I assume for matrices i'll need some busses on these perfboards. But how will they fit in a space saving manner on a 2,54mm grid? Unfortunately i couldn't find photos of similar projects on the web to see how others approach all this.

Draw your panel, divide the thing into sections. Perfboard/stripboard is useful if you have regular 0.1" spacing, also consider the different heights of components and group those of a similar/adjustable height (e.g. LEDs are versatile).

I suggest that you go for the direct wiring route. It's a much more linear way of solving the problem, and you're not constrained by fixed geometries. It's easy to address each element and to fix mistakes.