Hace mucho que no escribo por aca
Lo que les traigo ahora es un proyecto que tengo en la cabeza para clonar una Floorboard de line 6 de las viejas
Por que se preguntaran? :hombrecito:
2 Razones principales (intercambiables en cuanto a orden de prioridad)
1ro: Disponibilidad: Es un producto descontinuado y por tanto se esta volviendo dificl de conseguir.
2nd: PRECIO :risaverde: Me acabo de comprar un pod 2.0 que costo alrededor de 90 euros. No quiero gastar 150 euros en solo la pedalera :mellado:
Etapa de investigacion:
En contre un articulo muy util (en ingles) en el que un americano destripa una y saca la teoria de su funcionamiento. (lo reproduzco mas abajo porque el sitio esta caido, creditos al autor)
http://www.harmonicappliances.com/floor ... board.html
Tambien encontre algunas cosas aca
http://www.diystompboxes.com/smfforum/i ... ic=36555.0
La idea de la "escalera de resistencias" la tome de aca:
http://groups.google.com/group/rec.musi ... 19a3f15901
Como veran, el articulo esta bastante completo en cuanto al funcionamiento, pero no trae ningun circuito ya trazado asi que ahora viene la parte de la "ingenieria inversa" real :risamorada:Connections
The POD & Floor Board use standard "Category 5" network cables for connection. The connectors on these cables (and the receptacles in the POD and Floor Board) are known as RJ-45s. They're just like standard phone jacks, but with 8 pins.
The pin numbering I'll use for RJ-type jacks starts at 1 and goes from left to right looking into the receptacle (the female socket on the POD or Floor Board) with the locking tab slot on the bottom, like the diagram on the right. "Standard" or not, that's the numbering I'll be using here.
I'll be referring to the various signals from the POD's point of view. The switches and pedals are inputs, and the LEDs are an output.
Signals
The diagram on the right shows the connections at the RJ-45 receptacles in the POD and the Floor Board. The three inputs to the POD (the two pedals and the switches) are all analog, but the LED output is digital.
The two pedal inputs are implemented using LEDs and phototransistors, with a shaded plastic strip moving between them as you move the pedal. The output of each phototransistor drives a 2N4401 transistor, and the output of the 2N4401s is the input to the POD. When connected to an operating POD, I've measured voltage levels on the pedal inputs from 0.25V to 4.1V. On my unit the two pedals don't have exactly the same range (one only goes down to about 0.4V).
The POD has some very strange (to me, anyway) circuitry on its inputs that I assume are for protection of the POD, so I've also looked at the Floor Board independently. When it's connected to a 5V supply (no POD) with 10k pull-ups on the Wah and Volume lines, the voltage range is a little lower (0.2V to 3.7V).
The switches are implemented as a resistor ladder. Each switch taps the series of resistors at a different point, making a variable voltage divider. The resistances are arranged so that some combinations of multiple switches are also detectable (see below). The POD appears to have the equivalent of a 1k pull-up on the Switches line.
The LEDs are controlled by a series of digital pulses whose lengths determine the on/off outputs of four shift registers connected to the three 7-segment LEDs and the various single-purpose indicators.
Switch Input Details
As mentioned above, the switches are connected to some kind of resistor ladder. The table below gives both the input voltages measured at the POD and the resistances from the Switches pin to ground with the Floor Board disconnected from the POD.
LED Output Details
The LEDs line carries a series of pulses whose widths determines the states of the various LEDs in the Floor Board. The POD always sends 32 pulses per update, which refreshes all four of the shift registers that latch the states of all the LEDs. The pulses are routed through a 7414 inverter that uses the pulse width to generate the clock and data signals needed by the 74HC595 shift registers.
Long pulses (3µs high, 3µs low) turn LEDs off and short pulses (1µs high, 5µs low) turn LEDs on. The POD keeps the line low between transmissions. Generally, the POD only shifts out the LED pulses when there is a change in the LEDs, but if any of the LEDs is blinking they're updated every 120ms or so.
The four bytes of LED states are sent MSB (bit 7) first. I will call them D0, D1, D2 and D3, with D0 being the first byte sent. I'll use D0.n to indicate an individual bit in D0, where the value of n ranges from 0 (LSB) to 7 (MSB).
The picture to the right of the table shows which segments correspond to which bits.
The "pointer" LEDs are the ones off to the left of the Distortion and Bank Down labels that tell you whether you're the POD is using the Floor Board in Effect On/Off or Channel Select mode. The question marks about the Wah LED will be resolved the next time I can borrow a digital scope from work for a day or two – I forgot about the Wah LED when I first looked at it…
Unknowns
I don't really understand the circuitry just inside the POD. There are diodes that appear to be intended to protect the POD against voltage spikes, and there is a pull-up effect that seems to be equivalent to 10-15K on the pedals and 1k on the switches.
Con los datos de la tabla de resitencias de arriba empece por los switches.
Esta bastante claro el diagrama. Del pin 6 de la ficha tipo RJ45 entra a la "escalera de resistencias". En esa escalera cada switch esta conectado progresivamente a cada una de las resis sumando resistencia. Cuando se cierra uno de los switches a tierra el pod cambia.
Lo simule con Electronic Workbench y lo pase a la breadboard. Y funciona!!!
Use un potenciometro para la ultima resistencia(muy importante, sino el pod no responde como se debe) para los valores raros que no se consiguen use resistencias en serie (esta especificado en el diagrama)
