Difference between revisions of "Digital FD-8 pedal"
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Additionally (and optionally) we're adding: | Additionally (and optionally) we're adding: | ||
| − | * a switch (button) to start calibration | + | * a momentary switch (button) to start calibration |
* an LED, because every MCU project should have an LED | * an LED, because every MCU project should have an LED | ||
The circuit essentialy does the following: using the adc, the output voltage of the hall sensor is measured. This is then used to determine a corresponding resistance and that resistance value is programmed into the digital pots. Easy. | The circuit essentialy does the following: using the adc, the output voltage of the hall sensor is measured. This is then used to determine a corresponding resistance and that resistance value is programmed into the digital pots. Easy. | ||
Revision as of 02:08, 7 February 2014
In Roland FD-8 Issues: Hall Sensor Modification we described how a ratiometric hall sensor could replace the resistor film to solve reliability issues with the Roland FD-8 high hat pedals. Even though that Hall Sensor hack works, an MCU based approach might have some additional advantages:
- complete variable resistance to be compatible with other drum modules
- adjustable sensitivity curve
- detection of foot-down velocity (which is currently limited to one static velocity)
- auto-calibration, i.e. no need for pots to set the right trigger points.
We're currently working on a "more digital" version, based on a MCU and a digital potentiometer. We're using the following hardware:
- attiny13 MCU: 8-pin (6 io), 10-bit ADC.
- Two MCP41010 digital potentiometers in series (10K each, because when we sourced it, a single 50K version was a lot more expensive on ebay).
- Honeywell SS490 ratiometric hall effect sensor.
Additionally (and optionally) we're adding:
- a momentary switch (button) to start calibration
- an LED, because every MCU project should have an LED
The circuit essentialy does the following: using the adc, the output voltage of the hall sensor is measured. This is then used to determine a corresponding resistance and that resistance value is programmed into the digital pots. Easy.