Electrotap Teabox Sensor Interface (review)

Electrotap is a company formed by Tim Place and Jesse Allison. In addition to marketing Tim's ever-popular Tap. Tools externals for Max/MSP/Jitter and the Jade software, Electrotap now sells a hardware sensor interface called Teabox. Apparently, the box got its name from an early incarnation that used a tea box to contain the electronic circuitry. The first thing you notice about the Teabox is the rugged chassis design (see Figure 1). You can probably jump up and down on the thing and it wouldn't break. Although it looks very rugged, you might be disappointed, or relieved, to discover how light it actually is.

The unique feature of the Teabox is that, unlike other budget-priced interfaces that convert sensor voltages to MIDI, it converts voltages to digital audio data in the form of S/PDIF. There are several advantages to this, including speed, low latency, and resolution. The following table gives some figures published by the folks at Electrotap, supplemented by my own research (see Table 1).

Although these figures make the Teabox look very impressive next to its competitors, there are some advantages to the Teleo and Kroonde Gamma systems: the Teleo system

Figure 1.

View of Electrotap Teabox sensor interface.

Table 1.

Data comparisons of different sensor systems.

	MIDI	Teabox	Teleo	Kroonde Gamma
Number of times	43.47	4,000	100–	59–
data is updated	Hz	Hz	1,000	200
per second			Hz	Hz
Minimum latency	23.04	1.71	?	5–17
for any given sensor	msec	msec		msec
Maximum resolution	7 bits	12 bits	10 bits	10 bits
	(128 values)	(4,096 values)	(1,024 values)	(1,024 values)
Price	>US$ 149	US$ 425	US$ 189	US$ 1,495

allows digital and PWM output, and the Kroonde Gamma is wireless. These are both areas of development that Electrotap is looking into for future versions of the Teabox.

The Teabox has both optical- and RCA-type connectors for making the S/PDIF connection to your audio interface. Most audio interfaces come with S/PDIF connectors, and I tried the Teabox on an Mbox, a Digi001, an RME Multiface, and a G5 (there is a use for that optical I/O after all!). In any one of these cases you need to set the clock source to sync to the Teabox. The only interface I didn't know how to set the clock source on was the G5, but I quickly found a Mac OS X application called "Audio MIDI Setup" that allows you to configure the built-in hardware.

The Teabox is designed to handle up to eight continuous sensor inputs and 16 digital "toggle" inputs. For the continuous inputs there are four XLR/TRS connectors and eight 3-pin (I-Cube style) connectors on the front, and two RJ-11 (telephone) connectors on the back (each carrying up to four sensor inputs). Also on the back of the box are the four RJ-11 connectors for the 16 digital inputs (again, each carrying up to four inputs). The use of XLR connectors is unique to the Teabox. Using the XLR format has several advantages, including sturdiness, availability, and the fact that the cables can be shielded to minimize electromagnetic interference. The only question I would have about using XLR is that if Electrotap does go wireless, the connectors are very heavy. As for the I-Cube connectors, I have always had a problem with them. Firstly, although standard connectors can be modified to work with them, they are very hard to find, and secondly, they do not lock on, and become easily disconnected. RJ-11 connectors have become something of a favorite with my students. They are easy to find, connect by locking in, and are light.

For operation in Max/MSP, the only software you need to use with the Teabox are two externals: teabox~ and teabox.bits~. teabox~ is connected to your adc~ input, out-putting...