opensteno_qmk/docs/feature_haptic_feedback.md

Haptic Feedback

Haptic feedback rules.mk options

The following options are currently available for haptic feedback in rule.mk:

HAPTIC_ENABLE += DRV2605L

HAPTIC_ENABLE += SOLENOID

Known Supported Hardware

Name	Description
LV061228B-L65-A	z-axis 2v LRA
Mini Motor Disc	small 2-5v ERM

Haptic Keycodes

Not all keycodes below will work depending on which haptic mechanism you have chosen.

Name	Description
HPT_ON	Turn haptic feedback on
HPT_OFF	Turn haptic feedback on
HPT_TOG	Toggle haptic feedback on/off
HPT_RST	Reset haptic feedback config to default
HPT_FBK	Toggle feedback to occur on keypress, release or both
HPT_BUZ	Toggle solenoid buzz on/off
HPT_MODI	Go to next DRV2605L waveform
HPT_MODD	Go to previous DRV2605L waveform
HPT_DWLI	Increase Solenoid dwell time
HPT_DWLD	Decrease Solenoid dwell time

Solenoids

First you will need a build a circuit to drive the solenoid through a mosfet as most MCU will not be able to provide the current needed to drive the coil in the solenoid.

Wiring diagram provided by Adafruit

Select a pin that has PWM for the signal pin

#define SOLENOID_PIN *pin*

Beware that some pins may be powered during bootloader (ie. A13 on the STM32F303 chip) and will result in the solenoid kept in the on state through the whole flashing process. This may overheat and damage the solenoid. If you find that the pin the solenoid is connected to is triggering the solenoid during bootloader/DFU, select another pin.

DRV2605L

DRV2605L is controlled over i2c protocol, and has to be connected to the SDA and SCL pins, these varies depending on the MCU in use.

Feedback motor setup

This driver supports 2 different feedback motors. Set the following in your config.h based on which motor you have selected.

ERM

Eccentric Rotating Mass vibration motors (ERM) is motor with a off-set weight attached so when drive signal is attached, the off-set weight spins and causes a sinusoidal wave that translate into vibrations.

#define FB_ERM_LRA 0
#define FB_BRAKEFACTOR 3 /* For 1x:0, 2x:1, 3x:2, 4x:3, 6x:4, 8x:5, 16x:6, Disable Braking:7 */
#define FB_LOOPGAIN 1 /* For  Low:0, Medium:1, High:2, Very High:3 */

/* Please refer to your datasheet for the optimal setting for your specific motor. */
#define RATED_VOLTAGE 3
#define V_PEAK 5

LRA

Linear resonant actuators (LRA, also know as a linear vibrator) works different from a ERM. A LRA has a weight and magnet suspended by springs and a voice coil. When the drive signal is applied, the weight would be vibrate on a single axis (side to side or up and down). Since the weight is attached to a spring, there is a resonance effect at a specific frequency. This frequency is where the LRA will operate the most efficiently. Refer to the motor's datasheet for the recommanded range for this frequency.

#define FB_ERM_LRA 1
#define FB_BRAKEFACTOR 3 /* For 1x:0, 2x:1, 3x:2, 4x:3, 6x:4, 8x:5, 16x:6, Disable Braking:7 */
#define FB_LOOPGAIN 1 /* For  Low:0, Medium:1, High:2, Very High:3 */

/* Please refer to your datasheet for the optimal setting for your specific motor. */
#define RATED_VOLTAGE 2
#define V_PEAK 2.8
#define V_RMS 2.0 
#define V_PEAK 2.1
#define F_LRA 205 /* resonance freq */

DRV2605L waveform library

DRV2605L comes with preloaded library of various waveform sequences that can be called and played. If writing a macro, these waveforms can be played using DRV_pulse(*sequence name or number*)

List of waveform sequences from the datasheet:

seq#	Sequence name	seq#	Sequence name	seq#	Sequence name
1	strong_click	43	lg_dblclick_med_60	85	transition_rampup_med_smooth2
2	strong_click_60	44	lg_dblsharp_tick	86	transition_rampup_short_smooth1
3	strong_click_30	45	lg_dblsharp_tick_80	87	transition_rampup_short_smooth2
4	sharp_click	46	lg_dblsharp_tick_60	88	transition_rampup_long_sharp1
5	sharp_click_60	47	buzz	89	transition_rampup_long_sharp2
6	sharp_click_30	48	buzz_80	90	transition_rampup_med_sharp1
7	soft_bump	49	buzz_60	91	transition_rampup_med_sharp2
8	soft_bump_60	50	buzz_40	92	transition_rampup_short_sharp1
9	soft_bump_30	51	buzz_20	93	transition_rampup_short_sharp2
10	dbl_click	52	pulsing_strong	94	transition_rampdown_long_smooth1_50
11	dbl_click_60	53	pulsing_strong_80	95	transition_rampdown_long_smooth2_50
12	trp_click	54	pulsing_medium	96	transition_rampdown_med_smooth1_50
13	soft_fuzz	55	pulsing_medium_80	97	transition_rampdown_med_smooth2_50
14	strong_buzz	56	pulsing_sharp	98	transition_rampdown_short_smooth1_50
15	alert_750ms	57	pulsing_sharp_80	99	transition_rampdown_short_smooth2_50
16	alert_1000ms	58	transition_click	100	transition_rampdown_long_sharp1_50
17	strong_click1	59	transition_click_80	101	transition_rampdown_long_sharp2_50
18	strong_click2_80	60	transition_click_60	102	transition_rampdown_med_sharp1_50
19	strong_click3_60	61	transition_click_40	103	transition_rampdown_med_sharp2_50
20	strong_click4_30	62	transition_click_20	104	transition_rampdown_short_sharp1_50
21	medium_click1	63	transition_click_10	105	transition_rampdown_short_sharp2_50
22	medium_click2_80	64	transition_hum	106	transition_rampup_long_smooth1_50
23	medium_click3_60	65	transition_hum_80	107	transition_rampup_long_smooth2_50
24	sharp_tick1	66	transition_hum_60	108	transition_rampup_med_smooth1_50
25	sharp_tick2_80	67	transition_hum_40	109	transition_rampup_med_smooth2_50
26	sharp_tick3_60	68	transition_hum_20	110	transition_rampup_short_smooth1_50
27	sh_dblclick_str	69	transition_hum_10	111	transition_rampup_short_smooth2_50
28	sh_dblclick_str_80	70	transition_rampdown_long_smooth1	112	transition_rampup_long_sharp1_50
29	sh_dblclick_str_60	71	transition_rampdown_long_smooth2	113	transition_rampup_long_sharp2_50
30	sh_dblclick_str_30	72	transition_rampdown_med_smooth1	114	transition_rampup_med_sharp1_50
31	sh_dblclick_med	73	transition_rampdown_med_smooth2	115	transition_rampup_med_sharp2_50
32	sh_dblclick_med_80	74	transition_rampdown_short_smooth1	116	transition_rampup_short_sharp1_50
33	sh_dblclick_med_60	75	transition_rampdown_short_smooth2	117	transition_rampup_short_sharp2_50
34	sh_dblsharp_tick	76	transition_rampdown_long_sharp1	118	long_buzz_for_programmatic_stopping
35	sh_dblsharp_tick_80	77	transition_rampdown_long_sharp2	119	smooth_hum1_50
36	sh_dblsharp_tick_60	78	transition_rampdown_med_sharp1	120	smooth_hum2_40
37	lg_dblclick_str	79	transition_rampdown_med_sharp2	121	smooth_hum3_30
38	lg_dblclick_str_80	80	transition_rampdown_short_sharp1	122	smooth_hum4_20
39	lg_dblclick_str_60	81	transition_rampdown_short_sharp2	123	smooth_hum5_10
40	lg_dblclick_str_30	82	transition_rampup_long_smooth1
41	lg_dblclick_med	83	transition_rampup_long_smooth2
42	lg_dblclick_med_80	84	transition_rampup_med_smooth1

Optional DRV2605L defines

#define DRV_GREETING *sequence name or number*

If haptic feedback is enabled, the keyboard will vibrate to a specific sqeuence during startup. That can be selected using the following define:

#define DRV_MODE_DEFAULT *sequence name or number*

This will set what sequence HPT_RST will set as the active mode. If not defined, mode will be set to 1 when HPT_RST is pressed.