Mini Digital Oscilloscope DSO203
Discussion
I probably need to use an oscilloscope to monitor the switching of a lambda sensor and Max_Torque suggested this model.
In order to justify this purchase (to myself) can anyone advise how many other tasks I can perform with it?
I have some knowledge of electrics but very little electronics.
As an example if I wanted to perform the task above I have no idea how the scope is connected.....across the signal wires.....signal to earth.....wave the probe around in the general area.
Many thanks in advance.
Steve
In order to justify this purchase (to myself) can anyone advise how many other tasks I can perform with it?
I have some knowledge of electrics but very little electronics.
As an example if I wanted to perform the task above I have no idea how the scope is connected.....across the signal wires.....signal to earth.....wave the probe around in the general area.
Many thanks in advance.
Steve
I asked a similar question a while back but didn't get much by way of response. Thread here. I still am thinking of getting one but still haven't got one yet!
Steve_D said:
.....wave the probe around in the general area.
this is how a friend of mine thinks his car gets repaired, just wave some tools around the general area and it's fixed, lolIIRC - been over 10 yrs since i used an osci but, I think you have to piggyback the signal wires without disconnecting them, don't take my word fr it though as i'm not sure...
Steve_D said:
I probably need to use an oscilloscope to monitor the switching of a lambda sensor and Max_Torque suggested this model.
In order to justify this purchase (to myself) can anyone advise how many other tasks I can perform with it?
I have some knowledge of electrics but very little electronics.
As an example if I wanted to perform the task above I have no idea how the scope is connected.....across the signal wires.....signal to earth.....wave the probe around in the general area.
Many thanks in advance.
Steve
Pretty much anything electrical on a car can be checked with a suitable scope.In order to justify this purchase (to myself) can anyone advise how many other tasks I can perform with it?
I have some knowledge of electrics but very little electronics.
As an example if I wanted to perform the task above I have no idea how the scope is connected.....across the signal wires.....signal to earth.....wave the probe around in the general area.
Many thanks in advance.
Steve
From a simple voltage, to crank/cam sensors, testing injector and coil signals and almost any engine sensor, ABS sensors, speed sensors
The simple voltmeter/scope is handy, because not only does it tell you the voltage, but if for some reason there was a momentary drop in power, it would never be noticed on a meter. But it would be immediately apparent on a scope trace.
Basically any voltage or pulsed signal. With a clamp meter add on, it can also be used to monitor current too, although I dont have that feature myself.
I have a cheap USB based scope for the laptop, although really havent used it that much. If I had a hand held, would probably use it more. But the laptop does have a bigger screen, it can log for viewing after etc
Mine is the USB Stingray 2 channel scope with signal generator.
At the top end of the scale, Picoscope is meant to be the best, largely because of the customer support they offer.
Most of the crop of small scopes have a built in memory, so you can save a screens worth of data, and then upload it via USB etc.
That particular scope has 2 analalogue channels (50mV per division most sensitive to 10V per div least sensitive. However it comes with probes that can switch between a 1:1 input and a 10:1 input, so you can measure up to 500Vdc with it (carefully!). It only has 8 bit resolution, which means there are only 256 different voltage levels it can sample on each setting, against a "proper" scope that would be 12 or even 16 bit (4096 to 65535 levels!)
the screen has 8 divisions vertically, so on the most sensitive you can measure a 400mV (0.4V) signal, with a resolution of 1.56mV (0.00156V).
This means it is not particularly accurate but more than enough for the average automotive usage.
The X axis of the screen the "time base" is selectable from 1sec per div (12divs across whole screen = 12seconds) to 0.1uS (microsecond, one millionth of a second (1.2uS per screen)
As modern cars are so electronic, the number of things you could measure is almost infinite:
such as:
Crank and camshaft sensor signals
Injector pulse width
Coil pack firing signals
Boost control valve frequency or duty cycle
Wheel speed sensor frequency
Throttle potentiometer output voltage
Sensor drive voltages
Lambda sensor output or heat drive duty cycle
and that's before you get to the vast number of digital Buses in a modern car, so you can monitor a CAN or LIN bus for unexpected noise or attenuation etc!
It's one of those things you don't use everyday, but the one time you need it, it can save you hrs or even days of guessing!
The only negative i have about the DSO203 is that it is not that intuitive to use, and with it being so small, the buttons are even smaller! But after a couple of hrs playing around with it i'm finding it better to use that i initally thought.
Another benefit is that it has a built in signal generator, so can output various waveforms that could be handy, for example simulating a speed input to an ECU etc
That particular scope has 2 analalogue channels (50mV per division most sensitive to 10V per div least sensitive. However it comes with probes that can switch between a 1:1 input and a 10:1 input, so you can measure up to 500Vdc with it (carefully!). It only has 8 bit resolution, which means there are only 256 different voltage levels it can sample on each setting, against a "proper" scope that would be 12 or even 16 bit (4096 to 65535 levels!)
the screen has 8 divisions vertically, so on the most sensitive you can measure a 400mV (0.4V) signal, with a resolution of 1.56mV (0.00156V).
This means it is not particularly accurate but more than enough for the average automotive usage.
The X axis of the screen the "time base" is selectable from 1sec per div (12divs across whole screen = 12seconds) to 0.1uS (microsecond, one millionth of a second (1.2uS per screen)
As modern cars are so electronic, the number of things you could measure is almost infinite:
such as:
Crank and camshaft sensor signals
Injector pulse width
Coil pack firing signals
Boost control valve frequency or duty cycle
Wheel speed sensor frequency
Throttle potentiometer output voltage
Sensor drive voltages
Lambda sensor output or heat drive duty cycle
and that's before you get to the vast number of digital Buses in a modern car, so you can monitor a CAN or LIN bus for unexpected noise or attenuation etc!
It's one of those things you don't use everyday, but the one time you need it, it can save you hrs or even days of guessing!
The only negative i have about the DSO203 is that it is not that intuitive to use, and with it being so small, the buttons are even smaller! But after a couple of hrs playing around with it i'm finding it better to use that i initally thought.
Another benefit is that it has a built in signal generator, so can output various waveforms that could be handy, for example simulating a speed input to an ECU etc
Very few 'scopes go beyond 8-bit digitisation, the converters often work at 1 gigasamples/second or more, and doing conversion to such a depth at that speed starts to get complicated and expensive. It is rare that you would be doing such detailed work with a signal anyway. Especially with a car the signals are pretty crude and easy to see.
Basically it is a very fast and sensitive voltmeter that records the voltage as a graph on the screen. You clip one probe on the earth and another on the signal to be measured. Just don't go anywhere near the HT coil, it will fry your new shiny oscilloscope in a fraction of a second. Expensive automotive scopes have plenty of protection, cheap ones (and for that matter expensive ones) can't usually handle more than a few 10s of Volts. You could possibly just use a simple coil of wire and use it as an inductive pickup, or use a commercial HT probe.
Basically it is a very fast and sensitive voltmeter that records the voltage as a graph on the screen. You clip one probe on the earth and another on the signal to be measured. Just don't go anywhere near the HT coil, it will fry your new shiny oscilloscope in a fraction of a second. Expensive automotive scopes have plenty of protection, cheap ones (and for that matter expensive ones) can't usually handle more than a few 10s of Volts. You could possibly just use a simple coil of wire and use it as an inductive pickup, or use a commercial HT probe.
Coming from another field (physics grad), has anyone considered using one of the old-style, boxy analogue scopes as a piece of bench equipment? I know it'd be harder work to use, but they're significantly cheaper and have very good sensitivity/accuracy for their cost (certainly the equal of a sub-£200 hand DSO.
Obviously if storage is needed it's a moot point, but for scoping sensors live I'd say it's worth considering.
ETA: Anyone tried one of these Mini-scopes? ARM-powered with reasonable specs and very portable. At £47 it could be worth a try.
Obviously if storage is needed it's a moot point, but for scoping sensors live I'd say it's worth considering.
ETA: Anyone tried one of these Mini-scopes? ARM-powered with reasonable specs and very portable. At £47 it could be worth a try.
Edited by Krikkit on Friday 22 February 09:34
The scope linked above is less well spec'd than the DSO i linked too, as it only has 1 input channel (vs 2 analogue and 2 digital) and only a 1MHz bandwidth (vs a claimed 10MHz)
It can be usefull to have two inputs, for example you could read in the crank sensor input on one channel, and the ignition signal on the other and check the coil is actually being fired at the correct moment. That wouldn't be possible with a single channel device.
The 1MHz bandwidth (i.e. the ability to measure signals that varry at a frequency of up to 1MHz) is less of an issue for vehicle work, but could cause a slight limitation when trying to measure square wave signals like the PWM signal to a boost control solenoid (i won't go into why that is the case here for the sake of brevity).
If i only had £47 then the single channel scope is still way better than no scope, however, if i could afford the approx £120 two channel DSO i'd get that one!
I have 3 scopes:
1) Agilent bench scope - expensive but very very good
2) Fluke scopemeter - expensive but very robust and battery powered
3) miniDso - cheap but very easily transportable
On the bench for electronics work i use the Agilent.
For vehicle stuff, usually the Scopemeter as it is tough/robust
For emergency / occasional use i use the miniDSO.
However, the miniDSO is so small that i pretty much just take it everywhere in my laptop bag, so always have it availible. Even the not that big scopemeter is really a bit to big to do that with, so the miniDSO has a useful role!
It can be usefull to have two inputs, for example you could read in the crank sensor input on one channel, and the ignition signal on the other and check the coil is actually being fired at the correct moment. That wouldn't be possible with a single channel device.
The 1MHz bandwidth (i.e. the ability to measure signals that varry at a frequency of up to 1MHz) is less of an issue for vehicle work, but could cause a slight limitation when trying to measure square wave signals like the PWM signal to a boost control solenoid (i won't go into why that is the case here for the sake of brevity).
If i only had £47 then the single channel scope is still way better than no scope, however, if i could afford the approx £120 two channel DSO i'd get that one!
I have 3 scopes:
1) Agilent bench scope - expensive but very very good
2) Fluke scopemeter - expensive but very robust and battery powered
3) miniDso - cheap but very easily transportable
On the bench for electronics work i use the Agilent.
For vehicle stuff, usually the Scopemeter as it is tough/robust
For emergency / occasional use i use the miniDSO.
However, the miniDSO is so small that i pretty much just take it everywhere in my laptop bag, so always have it availible. Even the not that big scopemeter is really a bit to big to do that with, so the miniDSO has a useful role!
stevieturbo said:
When I google DS0203, some places are calling it a 4 channel ? Or is there a 4 channel version.
Most seem to be about £115
It is a four channel scope, but they are a bit cheeky because that is 2 x analogue channels (able to measure a constantly changing analogue voltage) and 2 x digital channels (only capable of detecting the edges or "changes" in a pure digital (square edged signal) signal.Most seem to be about £115
I've had one of these for 18 months or so.
Pros:
Reasonably cheap.
Small and light, and pretty robust with an alloy case.
Two analog channels with sufficient bandwidth for almost any car related use.
Reasonable battery life, and can be charged from any USB port.
Screen captures/waveform data can be transferred.
Built in waveform generator.
Cons:
The standard interface is simply horrific. It's borderline unusable and is the reason I have rarely used it.
Analog bandwidth is somewhat lower than the specs suggest due to a design problem.
Non-standard MCX connectors used on the scope probes, so you can't use standard scope probes with it if you lose or damage the supplied ones.
Triggering is not always reliable.
However, it's an open source project and there is now alternative application software which appears to be vastly more useable than the original, with extra features added.
Personally I would save up and get one of the better normal size Chinese DSOs, e.g. Rigol or clone which will be a more useful tool for the vast majority of jobs. There is a massive thread on the performance and hacking of these scopes on EEVBlog
Pros:
Reasonably cheap.
Small and light, and pretty robust with an alloy case.
Two analog channels with sufficient bandwidth for almost any car related use.
Reasonable battery life, and can be charged from any USB port.
Screen captures/waveform data can be transferred.
Built in waveform generator.
Cons:
The standard interface is simply horrific. It's borderline unusable and is the reason I have rarely used it.
Analog bandwidth is somewhat lower than the specs suggest due to a design problem.
Non-standard MCX connectors used on the scope probes, so you can't use standard scope probes with it if you lose or damage the supplied ones.
Triggering is not always reliable.
However, it's an open source project and there is now alternative application software which appears to be vastly more useable than the original, with extra features added.
Personally I would save up and get one of the better normal size Chinese DSOs, e.g. Rigol or clone which will be a more useful tool for the vast majority of jobs. There is a massive thread on the performance and hacking of these scopes on EEVBlog
Mr2Mike said:
Personally I would save up and get one of the better normal size Chinese DSOs, e.g. Rigol or clone which will be a more useful tool for the vast majority of jobs. There is a massive thread on the performance and hacking of these scopes on EEVBlog
I would agree with you if the scope were being used regulary and in a lab environment. However, because the DSO is so portable and cheap i don't mind taking it out into the field with me. Something that the non battey powered "bench top" scopes are just a bit compromised to do.I agree the UI is terrible, but after a bit of playing with it you get the hang of it tbh.
Max_Torque said:
I agree the UI is terrible, but after a bit of playing with it you get the hang of it tbh.
Have you tried the Gabonator firmware? I've been meaning to load it onto mine for a while, and this thread made me put my backside into gear and do it. The interface is so much better than the original that it really does transform the usefulness of this little scope. It's also includes numerous new features that may be of interest e.g. One wire interface, PID controller, chromatic tuner, async serial analyser, MIDI analyser.This month's Car Mechanics magazine has a review of various automotive oscilloscopes. They do seem rather in favour of the Pico USB ones, which in my experience are a nice idea, just chuffin expensive and rather clunky to use. I don't think I would ever trust a system that connected my laptop to several thousand volts.
I use an old analogue 'scope an awful lot, and they are perfectly fine for auto diagnostics. No, they don't tick all the man-maths boxes (digitisation, storage, colour, lcd, battery power etc etc) but they do the job well.
I use an old analogue 'scope an awful lot, and they are perfectly fine for auto diagnostics. No, they don't tick all the man-maths boxes (digitisation, storage, colour, lcd, battery power etc etc) but they do the job well.
Zad said:
This month's Car Mechanics magazine has a review of various automotive oscilloscopes. They do seem rather in favour of the Pico USB ones, which in my experience are a nice idea, just chuffin expensive and rather clunky to use. I don't think I would ever trust a system that connected my laptop to several thousand volts.
I use an old analogue 'scope an awful lot, and they are perfectly fine for auto diagnostics. No, they don't tick all the man-maths boxes (digitisation, storage, colour, lcd, battery power etc etc) but they do the job well.
Pico isnt intended for once a month use. And you arent just paying for the hardware. You're paying for the software and backup support.I use an old analogue 'scope an awful lot, and they are perfectly fine for auto diagnostics. No, they don't tick all the man-maths boxes (digitisation, storage, colour, lcd, battery power etc etc) but they do the job well.
I havent used one myself, but Ive never once heard a bad word about their setups. Anyone that has it thinks it is fantastic.
I'd say once you had a computer set up for easy use with it, it would be invaluable. Even if it meant just getting a cheap smallish laptop solely for that purpose
I wonder how many of them had used a conventional scope beforehand though? 99% of what people use expensive test gear for can be done with oldschool gear at 1/10th the price. Sure the Pico (and similar) scopes have some awesome functions, but in my experience those exotic bits hardly ever get used.
Speaking as a professional electronics developer, I'd never dedicate a laptop to drive a Pico. Far better to use a proper oscilloscope with a user interface which was designed for the job and doesn't involve shuffling around with a trackpad or dropping crud onto a computer.
Speaking as a professional electronics developer, I'd never dedicate a laptop to drive a Pico. Far better to use a proper oscilloscope with a user interface which was designed for the job and doesn't involve shuffling around with a trackpad or dropping crud onto a computer.
Zad said:
I wonder how many of them had used a conventional scope beforehand though? 99% of what people use expensive test gear for can be done with oldschool gear at 1/10th the price. Sure the Pico (and similar) scopes have some awesome functions, but in my experience those exotic bits hardly ever get used.
Speaking as a professional electronics developer, I'd never dedicate a laptop to drive a Pico. Far better to use a proper oscilloscope with a user interface which was designed for the job and doesn't involve shuffling around with a trackpad or dropping crud onto a computer.
So can a conventional scope be taken to remote sites, does it have a huge trace reference file available, does it instruct how to read/use various traces/sensors etc ?Speaking as a professional electronics developer, I'd never dedicate a laptop to drive a Pico. Far better to use a proper oscilloscope with a user interface which was designed for the job and doesn't involve shuffling around with a trackpad or dropping crud onto a computer.
A cheap laptop can be bought for sub £100. So why not dedicate it for that ? It means it leaves any other computer used in a workshop is free for other purposes. You can carry it about, if it gets damaged no big deal. Picoscope is designed for automotive diagnostics. A lab scope is not.
There may be some dedicated portable scopes about, but they are very very expensive, and still wont have the backup support for automotive use that the Pico has.
Again, that is where a large portion of the expense is. In that backup, not just the actual scope features. A normal lab scope will never offer that.
stevieturbo said:
There may be some dedicated portable scopes about, but they are very very expensive,
You can get a battery powered DSO with a much higher specification than a Picoscope for around £400. The Picoscopes are not good value for money IMO, but if you need the support that it comes with then there is little to touch it.And that i think leads me back to where i came in, the MiniDSO and their ilk. No, they are not brilliant at any one thing, but they are a jack of all trades, and more importantly, their small size and battery powered nature means you probably will have it with you when you need it!
And an average scope you have with you is worth a whole lot more than an all-singing all-dancing one that is sitting on the bench at home.......... ;-)
And an average scope you have with you is worth a whole lot more than an all-singing all-dancing one that is sitting on the bench at home.......... ;-)
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