DLP Designs A/D Converter $30
http://www.dlpdesign.com/usb/io8.shtml
DLP designs has created a 8 channel USB powered data acquisition card. It allows for eight 0-5 volt inputs, and provides a 5 volt output for powering your sensors. It is fast, and appears to be the cheapest DAQ option on the market right now. It interfaces with Nistune, allowing logging and monitoring of up to 8 channels.
Sensors
Temperature (intake) ($5)
http://search.digikey.com/scripts/DkSea ... 8B20%2B-ND
This thermometer is made by Dallas Semiconductor. It requires Ground, 5v input, and outputs a linear 0-5v signal. It has a sensing range of -55ºC to 125ºC; perfect for monitoring inlet air temperatures. It is fast, and accurate within a couple of degrees. The are $5 on digikey.com
MAP Sensor ($10 or Free)
http://www.freescale.com/webapp/sps/sit ... de=MPX4250
All of the MAP sensors on the market are $50 and above. Alternatively you may be able to find a GM 3bar sensor in a junkyard. OR you could purchase the motorola MPX4250. This is a 2.5bar MAP sensor designed for automotive applications. It is fast, and accurate within .5psi. It requires ground, 5 volts input, and it outputs a linear 0-5v signal. If you ask freescale.com nicely, they will send you free samples. Otherwise they can be ordered from digikey.com. If your clever, you can also buy the harness for these sensors. I just wired it myself, whatever.
Exhaust Gas Temp ($35 plus probe)
http://www.o2simulator.com/index.php?ma ... ucts_id=13
Logging EGT requires a K-type thermocouple and an amplifier. Unfortunately, most the amplifiers on the market, both lab use and automotive use are $150 to $300 and multichannel. AEM sells a nice unit, if thats what your looking for. If you only want a single channel, buy the above converter, and any high temp K-type thermocouple (ebay, whatever). A thermocouple outputs a mV, non-linear signal. The amplifier/converter changes the signal to linear 0-5V output. Alternatively, you can make your own amplifier converter using this little surface mount chip from digikey and a few resistors ($10 or less cost). There are guides all over the internet on how to do this. IMO, just buy the pre-made circuit.
Wideband Logging
Most Widebands have a semi-linear 0-5 volt output. Nistune supports many of these. IF nistune does not support your wideband, you can use the DLPDesigns board to log your wideband. This is the easiest way to log an AEM UEGO gauge.
Detonation Monitoring ($10)
Okay, this method doesnt actually log detonation through a channel of the DLP designs board. Using the 5v signal and ground from the DLP designs board, you can power a 3-wire condenser microphone. Simply JB weld the condenser microphone to your factory detonation sensor, and supply the output signal to a headphone jack. Use your computer and a sound recording program to listen to the microphone. This works amazingly well, and is better explained on many other automotive forums.
If you dont want to use your laptop (or it doesnt have a line-in) you can use a cheap tape recorder, or build your own amplifier circuit: http://home.netcom.com/~bsundahl/knock/ ... listen.htm
Wiring
So you have several sensors which all require 5 volts and ground. The sensor can share ground and 5volt signals, which can be provided from the DLPdesigns converter. Each sensor will require its own output signal wire. The easiest way to "build" a sensor harness is to simply use a CAT 5 ethernet cable. An ethernet cable has 8 wires bundled inside it. It works well, and it allows your entire system to be mobile. Since everything is on one harness, you can transfer it all to whichever car your working on.
