arstechnica.com— The Minnesota Supreme Court says that a defendant is entitled to see the source code for the Intoxilyzer breath tester.
Aug 9, 2007View in Crawl 4
The source code would be meaningless without knowing other specific details of the design. As a simple example, let's say the alcohol sensor in the breathalyser varies its resistance based on the amount of alcohol in the breath. The variable resistance is converted to a variable voltage using a voltage divider with an adjustable divisor (used for calibration) which drives an ADC circuit. The output of the ADC is then fed into a microprocessor which interprets the binary number and, using a mathematical formula, converts it to a BAL and then displays the result on the screen. In this design, simply having the source code that the microprocessor executes wouldn't help much as it wouldn't give you specific details about the alcohol sensor's resistance curve or error rate, details on the ADC and its error rate, knowledge of how the machine was calibrated, or other factors such as whether or not the machine was cleaned after its previous use or how that would affect the reading. All you'd see is "read number from ADC, do some math, display result" which wouldn't tell you much. It would be like saying you could check your car for optimal performance by reading the ECU source code. This "defense" reeks of a stall tactic used to buy time or instill reasonable doubt on a jury. In the state I live in, a first time DUI offense is punishable mostly by probation and community service so if the defendant in this case is taking it to this level, then chances are it's not his first offense. If he really is a repeat drunk driver, I hope they throw the book at him as he's a danger to anyone who makes the mistake of being on the road with him.
Asking how something works is different from viewing the source code, so no, of course I wouldn't think it's unfair to ask how a machine worked. That's simply curiosity. But assuming that's not the main focus of your argument, I'd say it's completely fair to test the machine yourself. Not test as in inspect the source code, test as in run a controlled set of experiments. Note that I said black box. For example, if you wanted to test a cop's speed radar, you could (well not you personally, but someone with the resources and funds could) set up tests with different vehicles, of different materials / colors / whatever, going at a controlled set of speeds, and see if the speed radar's results correlate to reality. You don't need to open up the damn thing to test that it works.
I say it's a minor inconvenience relative to not walking ever again. And was that the first time you drank and drove, or just the first time you got caught? And if a year in jail was at risk, would you have done it in the first place? They system may have worked for you, but I'm afraid you are in the minority. The number of repeat DUI offenders is astounding. The system doesn't work. I'm going to stay on my soap box and annoy people who drink until the day I die. I have never had a drop of alcohol in my life....and I never will. It's poison and we treat it like it is the nectar of the gods. And the only reason we have this problem is because people think they can't have as much fun without alcohol. It's ridiculous....the victims are purely innocent...and I'm sick of it.
No. What he said was that people experience a different feeling of intoxication because they become accustom to being drunk. In order to prove his point, he would have to show that people who of the same BAC who felt different performed differently on the road.Furthermore, your logic is flawed. From a logical perspective his argument's value is 0 because I disproved his premise; therefore, his conclusion is invalid.
Great, but if they drop the brethalizer reading they may still be able to convict. All they need to do is show operation of a motor vehicle and impairment. If he gets the breathalizer dropped, i guess it comes down to the officers report and the field sobriety test.
tephraAug 10, 2007
what a tool - seriously drink driving isn't funny!
bylethAug 10, 2007
The source code would be meaningless without knowing other specific details of the design. As a simple example, let's say the alcohol sensor in the breathalyser varies its resistance based on the amount of alcohol in the breath. The variable resistance is converted to a variable voltage using a voltage divider with an adjustable divisor (used for calibration) which drives an ADC circuit. The output of the ADC is then fed into a microprocessor which interprets the binary number and, using a mathematical formula, converts it to a BAL and then displays the result on the screen. In this design, simply having the source code that the microprocessor executes wouldn't help much as it wouldn't give you specific details about the alcohol sensor's resistance curve or error rate, details on the ADC and its error rate, knowledge of how the machine was calibrated, or other factors such as whether or not the machine was cleaned after its previous use or how that would affect the reading. All you'd see is "read number from ADC, do some math, display result" which wouldn't tell you much. It would be like saying you could check your car for optimal performance by reading the ECU source code. This "defense" reeks of a stall tactic used to buy time or instill reasonable doubt on a jury. In the state I live in, a first time DUI offense is punishable mostly by probation and community service so if the defendant in this case is taking it to this level, then chances are it's not his first offense. If he really is a repeat drunk driver, I hope they throw the book at him as he's a danger to anyone who makes the mistake of being on the road with him.
Closed AccountAug 10, 2007
the awesomeness of your nerdiness makes me smaile/weep.
ozydingoAug 10, 2007
Asking how something works is different from viewing the source code, so no, of course I wouldn't think it's unfair to ask how a machine worked. That's simply curiosity. But assuming that's not the main focus of your argument, I'd say it's completely fair to test the machine yourself. Not test as in inspect the source code, test as in run a controlled set of experiments. Note that I said black box. For example, if you wanted to test a cop's speed radar, you could (well not you personally, but someone with the resources and funds could) set up tests with different vehicles, of different materials / colors / whatever, going at a controlled set of speeds, and see if the speed radar's results correlate to reality. You don't need to open up the damn thing to test that it works.
svpirateAug 10, 2007
An independent calibration test wouldn't necessarily show up incorrectly if there is a glitch in the unit's coding.
groverblueAug 10, 2007
best link ever...
frogman54Aug 10, 2007
I say it's a minor inconvenience relative to not walking ever again. And was that the first time you drank and drove, or just the first time you got caught? And if a year in jail was at risk, would you have done it in the first place? They system may have worked for you, but I'm afraid you are in the minority. The number of repeat DUI offenders is astounding. The system doesn't work. I'm going to stay on my soap box and annoy people who drink until the day I die. I have never had a drop of alcohol in my life....and I never will. It's poison and we treat it like it is the nectar of the gods. And the only reason we have this problem is because people think they can't have as much fun without alcohol. It's ridiculous....the victims are purely innocent...and I'm sick of it.
tlowAug 11, 2007
No. What he said was that people experience a different feeling of intoxication because they become accustom to being drunk. In order to prove his point, he would have to show that people who of the same BAC who felt different performed differently on the road.Furthermore, your logic is flawed. From a logical perspective his argument's value is 0 because I disproved his premise; therefore, his conclusion is invalid.
parentApr 26, 2010
Great, but if they drop the brethalizer reading they may still be able to convict. All they need to do is show operation of a motor vehicle and impairment. If he gets the breathalizer dropped, i guess it comes down to the officers report and the field sobriety test.