MilliKey Response Box

MilliKey Response Box Animation
Collect Accurate Manual Responses
Using a MilliKey could not be easier. Connect the MilliKeys' USB cable to your computer and it automatically detects the MilliKey Keyboard. MilliKey button events generate standard keyboard events with millisecond precision and 1 millisecond average latency.

Several different MilliKey box sizes are available for single handed, two handed, and desktop use. MilliKey MH and LH Models use interchangeable button caps, allowing use of Clear or Color Button Cap Pack Options, to best meet your research needs.


Test MilliKey Keyboard Event Latency
MilliKey Keyboard press events have an average of one millisecond latency with sub-millisecond variability. Want to test this yourself? No problem! Every MilliKey includes timing validation procedures that require no additional hardware.

In contrast, standard keyboards are typically poor manual response devices because of long and variable event delays which cannot even be tested without additional equipment that can be expensive and complicated to use.
Keyboard vs. MilliKey Graph


MilliKey Delux Light Sensor Upgrade
Test Visual Stimulus Onset Latency
The MilliKey DeLux Light Sensor Upgrade allows MilliKey MH and LH models to detect changes in experiment display brightness and generate a keyboard or serial event when the light level crosses a configurable digital threshold. This information can be used to calculate the difference between reported and actual stimulus onset times.
The LabHackers Device Manager can be used to configure light sensor trigger settings and to collect and view light sensor data.


Model Comparison & Pricing
Model Case Size
W x L x H
Button Size Button Colors Price
SV-2 SV-2 6.5 x 13 x 2.6 cm
2.6 x 5.1 x 1.0 inch
16 mm
0.63 inch
Red Green Yellow Burgandy Black $199 USD
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SV-4 SV-4 6.5 x 13 x 2.6 cm
2.6 x 5.1 x 1.0 inch
16 mm
0.63 inch
$209 USD
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SH-2 SH-2 13 x 6.5 x 2.6 cm
5.1 x 2.6 x 1.0 inch
16 mm
0.63 inch
$199 USD
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SH-4 SH-4 13.0 x 6.5 x 2.6 cm
5.1 x 2.6 x 1.0 inch
16 mm
0.63 inch
$209 USD
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MH-4 MH-4 17 x 8.6 x 3.5 cm
6.7 x 3.4 x 1.4 inch
24 mm
0.95 inch
White Red Green Yellow Pink Blue Black $249 USD
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MH-5 MH-5 17 x 8.6 x 3.5 cm
6.7 x 3.4 x 1.4 inch
24 mm
0.95 inch
$259 USD
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MH-6 MH-6 17 x 8.6 x 3.5 cm
6.7 x 3.4 x 1.4 inch
24 mm
0.95 inch
$269 USD
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LH-4 LH-4 22 x 14 x 4 cm
8.7 x 5.5 x 1.6 inch
30 mm
1.2 inch
White Red Green Yellow Pink Blue Black $269 USD
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LH-8 LH-8 22 x 14 x 4 cm
8.7 x 5.5 x 1.6 inch
30 mm
1.2 inch
$309 USD
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All MilliKey models can be built with custom button hole positions in the case.
Please see the Custom Button Layout option below.

Download Comparison Chart PDF

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Options
MilliKey
Delux Upgrade
MilliKey Custom Response Box Upgrade the MilliKey Response Box with a 3.5mm input jack and one MilliKey DeLux Light Sensor attachment.
Available for all MilliKey MH and LH models.
$149 USD
Custom
Button Layout
MilliKey Custom Response Box MilliKey built with custom button positions. $49 USD
24mm Button - Clear Cap Pack
(CP24-CLKW-8)
24mm Clear Cap Pack Interchangeable Clear Button Pack for 24mm buttons comes with four black and four white caps, and one cap removal pin.
Compatible with MilliKey MH-4, MH-5, and MH-6 models.
$25 USD
24mm Button - Color Cap Pack
(CP24-CMIX-12)
clear cap pack Interchangeable Color Button Pack for 24mm buttons comes with
two each of black, blue, red, green, yellow, pink caps, and one cap removal pin.
Compatible with MilliKey MH-4, MH-5, and MH-6 models.
$25 USD
30mm Button - Clear Cap Pack
(CP30-CLKW-8)
clear cap pack Interchangeable Clear Button Pack for 30mm buttons comes with four black and four white caps, and one cap removal pin.
Compatible with MilliKey LH-4 and LH-8 models.
$30 USD
30mm Button - Color Cap Pack
(CP30-CMIX-10)
clear cap pack Interchangeable Color Button Pack for 30mm buttons comes with two each of black, blue, red, green, yellow caps, and one cap removal pin.
Compatible with MilliKey LH-4 and LH-8 models.
$25 USD

Features
1000 Hz USB Keyboard

A MilliKey response box is automatically detected as a 1000 Hz USB Keyboard when connected to the USB port of a computer.

Pressing a button on a MilliKey generates a standard Keyboard press event with a one millisecond reporting rate and average delay. No debounce period is applied to press events.

When a MilliKey button is released, the corresponding USB keyboard release event is generated after a 15 millisecond debounce interval. The debounce duration should be subtracted from keyboard release timestamps to achieve accurate key press durations within experiment software.

The key that is used for each MilliKey button (up to 8) is easily changed using the Device Manager application.

OS and Software Compatible MilliKey Response Boxes work on Windows 7 / 10, macOS 10.7+, and Linux.

Connect MilliKeys' USB cable to your computer and immediately start collecting MilliKey generated keyboard events from within DirectRT, Experiment Builder, E-Prime, Presentation, Psychopy, PsychophysicsToolbox, PsyScope, SuperLab, or any other Psychology experiment software.

The MilliKey USB serial interface is plug-and-play on Windows 10 and macOS; and gets up and running on Windows 7 and Linux easily too.

MilliKey Timing Validation

Millisecond accurate MilliKey Timing Validation procedures are integrated into every MilliKey Response Box. No additional hardware required.

MilliKey Hardware Timing: Use the Device Manager application to easily gather statistics about MilliKey event latency on the computer being tested.

Software's Keyboard Time-Stamping Accuracy: Test the time-stamping accuracy of your experiment software for MilliKey Keyboard events by programmatically instructing the MilliKey device to generate keyboard events with millisecond accuracy.

MilliKey DeLux Upgrade

The MilliKey Delux Light Sensor allows the MilliKey to read the brightness of the computer monitor being used and generate a keyboard or serial event when display brightness crosses a configurable threshold level. The MilliKey DeLux upgrade includes an analog input port on the MilliKey enclosure and a DeLux Light Sensor connected to a 2 meter cable.

LabHackers Device Manager

LabHackers Device Manager is an application that makes it easy to adjust MilliKey response box settings. Change button to keyboard key mappings and button release debounce time.

MilliKey hardware timing can also be evaluated by using the MilliKey Timing Validation dialog within Device Manager.

1000 Hz USB Serial

Every MilliKey response box can also be accessed via a USB serial interface. No additional cables are needed. The MilliKey USB serial interface can be used in a command or data streaming mode:

Command Mode: Send commands to the MilliKey device to configure device settings or to instruct the MilliKey to generate a keyboard press and release event with millisecond accuracy.

Streaming Mode: Switch the MilliKey Serial interface into a 1000 Hz button state data stream that gives the state of all MilliKey buttons exactly once a millisecond. This is a good way to accurately access MilliKey button data when using software that does not reliably time stamp keyboard events.

Download Features PDF

Technical Specifications
Supported Operating Systems Windows 10 / 7, macOS, and Linux
Supported Experiment Software Keyboard Events: Any
USB Serial: Any software that allows reading / writing to a Serial port.
USB Connection Type Full Speed USB 2 Type A (compatible with USB 3)

Use of a USB C port requires a USB C to USB 2 adapter (sold separately).

Max. Simultaneous Buttons Pressed 8
USB Keyboard Event Sampling Rate 1000 Hz (1000 per second)
USB Serial Sampling Rate 1000 Hz (1000 per second)
Internal Button Scan Rate

The internal frequency at which button inputs are read and processed is based on the number of buttons:

# Buttons Button Scan Rate
280 kHz (80,000 per second)
470 kHz (70,000 per second)
660 kHz (60,000 per second)
850 kHz (50,000 per second)
Button Release Debounce Interval 15 millisecond (configurable)
Button 1 - 6 Keyboard Mappings Each of the first six MilliKey buttons can be associated with one of the following keys.
Each button must be assigned to a unique key.

A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z
0, 1, 2, 3, 4, 5, 6, 7, 8, 9
F1, F2, F3, F4, F5, F6, F7, F8, F9, F10, F11, F12
', `, ",", ., /
RIGHT, LEFT, UP, DOWN, PAGE_UP, PAGE_DOWN
ENTER, ESC, BACKSPACE, TAB, SPACE, PRINTSCREEN, PAUSE, INSERT, HOME, DELETE, END
NUM_1 - NUM_9, NUM_SLASH, NUM_ASTERIX, NUM_MINUS, NUM_PLUS, NUM_ENTER, NUM_PERIOD

Default Values
Button Default Key
11
22
33
44
55
66
Button 7 and 8 Keyboard Mappings On MilliKey models with 8 buttons, button 7 and 8 can be assigned to one of the following modifier keys:
SHIFT, CTRL or ALT.

Using modifier keys for buttons 7 and 8 allow for all eight MilliKey buttons to be pressed at the same time without missing any events.

Default Values:
Button Default Key
7SHIFT
8CTRL
Button Press Event Delay1 1 millisecond
Button Release Event Delay1 Debounce milliseconds (default: 15 msec) after the physical release event is first detected.

Note: The debounce period should be subtracted from any MilliKey release event timestamps calculated by your experiment software.
USB Serial Interface Windows 10 and macOS automatically register each MilliKey as a USB Serial device.

Windows 7 requires a USB Serial driver to be installed. Download it thanks to PJRC.

Linux needs UDEV rule change. Download it thanks to PJRC.
Upgradeable Firmware Yes, using LabHackers Device Manager.
MilliKey DeLux Light Sensor
Sampling Rate10,000 Hz
AD Resolution16 bit
USB Event Delay1 msec
Case Size See MilliKey Model Comparison table
Button Size
Button Colors
Button Count
Case Material ABS Plastic (Black)
1 Computer Configuration can impact the ability of your computer to read any USB HID device at 1000 Hz. This can potentially result in increased event latencies (higher mean and stdev). Regardless of the keyboard device or experiment software being used, it is the experiment software that is responsible for accurately time-stamping the keyboard events as they are received. Therefore, the actual accuracy of the keyboard press / release times can not be known without a way to actually test it.
MilliKey is the first, and only, response box with the ability to easily test both of these potential sources of error, without the need for any extra hardware. MilliKey Timing Validation can provide sub-millisecond accurate information on: a) the actual latency of MilliKey keyboard events on the computer being tested and b) the accuracy of your experiment softwares' time-stamping of MilliKey keyboard events.
Download Technical Specifications PDF