inglewoodpete
Senior Member
And with the Euro in freefall...
(Actually it's not but I had to throw that in
).
(Actually it's not but I had to throw that in
).Your opinion counts - questions regarding simple but usable oscilloscope
- Thread starter womai
- Start date
Andres Rodriguez
New Member
I assembled the LCS-1M some time ago and still use (more often than my Tektronix). At that time you were selling the PCB and provided a bill of materials with JAMECO part numbers. How do you plan to sell this one?
I'm ready to place an order.
Andres Rodriguez
I'm ready to place an order.
Andres Rodriguez
At least in the beginning I will sell complete kits. I get good price breaks by ordering in bulk (and made an effort to choose good-quality components at lowest possible cost), plus as mentioned I got some components for free from John West, so I believe I'll be able to offer it for the same or less someone could buy the components himself (not even counting the time required). I'll still put the component list and the full schematic online of course so anybody can see for himself. But I honestly think nobody can produce something that still looks and feels like a real scope & logic analyzer (e.g. wide input signal range and decent protection against overvoltage) for less than this instrument. Also when ordering there is always the tradeoff of getting everything from one vendor (but some components will be more pricey than you could get them from some other place) and pay shipping only once, or procure the components from several vendors, thus minimizing component cost but at the same time you'll have to pay shipping fees several times. For a one-off this tends to make the purchase expensive either way. For bulk orders the second solution is better because shipping cost becomes a minor part of the overall cost, reducing per-unit cost further.
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premelec
Senior Member
@womai - thanks for persisting in this worthy project! I suggest you get someone totally unfamiliar with the unit to assemble a kit and give you feedback on the instructions you've worked out. This has the advantage of saving you time and finding out what you may have been blind to... [If the questions start coming in after you've sent out the kits it takes a lot of time... ]. Good wishes for early completion ! [sure I'll assemble one and comment if you wish... I've assembled hundreds of electronic kits over decades... with and without good instructions -learning de-soldering skills...]
[If the questions start coming in after you've sent out the kits it takes a lot of time... ]. Good wishes for early completion ! [sure I'll assemble one and comment if you wish... I've assembled hundreds of electronic kits over decades... with and without good instructions -learning de-soldering skills...]Andres Rodriguez
New Member
Sonds great I'm ready to buy.
I'm pretty psyched - just managed to pump up the maximim datalogger sampling rate to 1 MSa/sec. That's definitely enough to look at 100 kHz I2C. And the best part, it now gets full record length (860 samples per channel) even at this fast rate. Needed some pretty tight coding...
As far as I can tell all the hooks I need are in the firmware, even some for possible future improvements - though a few minor ones are yet to be fully tested. That way I will be able to release the hardware and put the kits online while still tidying up and improving the PC software.
As far as I can tell all the hooks I need are in the firmware, even some for possible future improvements - though a few minor ones are yet to be fully tested. That way I will be able to release the hardware and put the kits online while still tidying up and improving the PC software.
Finally managed to sublicense a USB VID/PID (vendor/product ID) from Microchip - first two tries (last year) got me no answer from them whatsoever, but third time is a charm it seems And you definitely get more than you pay for since they give it out for free. So that means I can officially distribute the scope without running afoul of the USB consortium's regulations requiring every device to have a unique VID/PID combination. At least as long as I don't sell more than 10000 devices - no big risk there...
And you definitely get more than you pay for since they give it out for free. So that means I can officially distribute the scope without running afoul of the USB consortium's regulations requiring every device to have a unique VID/PID combination. At least as long as I don't sell more than 10000 devices - no big risk there...Just a little teaser... guess what the picture below shows!
Right, that's the first batch of scope kits coming into existence. Still need to put in (and test!) a few hooks for possible future extensions into the microcontroller firmware, but that should be done the next few days. Also need to build up one of the kits myself to prove the new PCB works, I did not forget any components, and in the process put together the assembly guide with lots of pictures. I'll keep everybody posted about progress. Getting closer!
Right, that's the first batch of scope kits coming into existence. Still need to put in (and test!) a few hooks for possible future extensions into the microcontroller firmware, but that should be done the next few days. Also need to build up one of the kits myself to prove the new PCB works, I did not forget any components, and in the process put together the assembly guide with lots of pictures. I'll keep everybody posted about progress. Getting closer!
mrburnette
Senior Member
OH, you said "KIT", not skit... I guess we all should be happy that you are intent on playing around with electronic parts and not biological ones!
DPScope SE - It's alive!
Just finished assembling one of the kits. Indeed discovered that I left out one capacitor (already ordered a set for the other kits) and tweaked the compensation capacitors. The instrument was alive right away and works like a charm. In the process I also took the pictures I'll need for the step-by-step assembly guide - this document and the user manual are next on my list before I put the kits, software and documentation online. Only a few more days I hope.
As a teaser, here are a few pictures of the complete unit. Enjoy! Note the logic analyzer port on the back, as well as the external trigger (T).
Wolfgang
Just finished assembling one of the kits. Indeed discovered that I left out one capacitor (already ordered a set for the other kits) and tweaked the compensation capacitors. The instrument was alive right away and works like a charm. In the process I also took the pictures I'll need for the step-by-step assembly guide - this document and the user manual are next on my list before I put the kits, software and documentation online. Only a few more days I hope.
As a teaser, here are a few pictures of the complete unit. Enjoy! Note the logic analyzer port on the back, as well as the external trigger (T).
Wolfgang
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westaust55
Moderator
A very professional, well laid out and useful piece of equipment.
Congratulation on your endeavors Wolfgang.
Congratulation on your endeavors Wolfgang.
Andres Rodriguez
New Member
Great job
Great job Wofgang. I have one of the LCS-1M-28X2-XY you designed sometime ago. Works great but would like to get your new creation, I am in line waiting for the release.
Great job Wofgang. I have one of the LCS-1M-28X2-XY you designed sometime ago. Works great but would like to get your new creation, I am in line waiting for the release.
inglewoodpete
Senior Member
It's looking really good, Wolfgang. This will bring a modest but quite powerful oscilloscope within the reach of many hobbiests and schools.
Is there an updated specification and/or website that we can see yet?
Is there an updated specification and/or website that we can see yet?
No, the website will come in a few days. First I want to have the documents ready, that will avoid having to answer the same questions over and over again The website will get merged into the existing DPScope website at http://www.dpscope.com - the spec will be part of the website. But in a nutshell
Scope:
Datalogger:
Logic analyzer:
Connection:
The PC software is about 98% complete. It's fully practically usable but I need to update a few features like save/load setup, export digital waveforms, automated offset compensation etc. I'll finish that once the scope is out. Can do this even with instruments already in the field, the necessary hooks are already in the microcontroller firmware.
Wolfgang
The website will get merged into the existing DPScope website at http://www.dpscope.com - the spec will be part of the website. But in a nutshellScope:
- Two channels
- Max. input +/-25V (protected to > 100V), scale 50mV/div ... 2V/div
- Input impedance 1 MOhm || 17 pF
- Can use standard scope probes (either 1:1 or 1:10, but you will need to adjust offset trimmers between these two)
- Analog bandwidth > 300 kHz
- Sample rate 10 Sa/sec ... 20 kSa/sec per channel real-time, 50 kSa/sec with channels alternating, up to 2 MSa/sec equivalent time (for repetitive signals)
- Trigger: auto, CH1, external; trigger on rising or falling edge
- Adjustable trigger level for CH1, fixed at 1.5V for external trigger input (usable for TTL, 5V CMOS, 3.3V CMOS, 2.5V CMOS)
- Max. trigger rate approx. 60 kHz
- Record length 200 points per channel
- Acquisition: single shot, repetitive, averaging
- FFT (real-time frequency spectrum display) up to 25 kHz (i.e. covers audio range)
- Many automated measurements like amplitude, frequency, etc.
Datalogger:
- 2 analog channels, 4 digital channels
- analog specs (voltage range etc.) same as scope
- sample rate 10 samples/sec ... 1 sample/hour
- direct log to file
Logic analyzer:
- 4 digital input channels
- Sample rate (real time, good for single shot) 10 Sa/sec ... 1 MSa/sec
- Digital threshold: TTL compatible, thus good for TTL, 5V CMOS, 3.3V CMOS, 2.5V CMOS
- Record length ~850 points
- Trigger: auto, CH1, CH2, CH3, CH4; rising or falling edge
Connection:
- USB for both data and power
- No drivers needed (uses Windows HID device driver); custom VID/PID (sub-licensed from Microchip) so no conflicts with other devices possible
- Uses approx. 70mA
The PC software is about 98% complete. It's fully practically usable but I need to update a few features like save/load setup, export digital waveforms, automated offset compensation etc. I'll finish that once the scope is out. Can do this even with instruments already in the field, the necessary hooks are already in the microcontroller firmware.
Wolfgang
premelec
Senior Member
Wonderful! ["Max. input +/-25V (protected to > 100V)..." could be "protected up to 110V" ; probably best to specify some cutoff for the Van De Graaf & neon sign transformer kids... ]
Will the program run on old Windows... how old? [95?] I've got some old laptops that might just want to live on as oscilloscopes... Thanks for your good work!
] Will the program run on old Windows... how old? [95?] I've got some old laptops that might just want to live on as oscilloscopes... Thanks for your good work!
No need to worry, the ">100V" will not be included in the official spec. It will simply say "+/-25V max". If you exceed that you will be on your own and I explicitly decline any responsibility. I like to have a good amount of safety margin in these parameters!
I haven't tested it on anything older than XP. Win95 does not have native USB support so I doubt it will work there. The instrument runs as a HID (human interface device) class peripheral - I think XP was the first Windows that included drivers for this class out of the box. HID is nice because one does not need to install any extra drivers - just plug in the instrument and second later you are up and running!
I haven't tested it on anything older than XP. Win95 does not have native USB support so I doubt it will work there. The instrument runs as a HID (human interface device) class peripheral - I think XP was the first Windows that included drivers for this class out of the box. HID is nice because one does not need to install any extra drivers - just plug in the instrument and second later you are up and running!
Wolfgang I've been looking back to the history of your post back in 7/2010 as follows:
http://www.picaxeforum.co.uk/showthread.php?15814-Interest-in-very-simple-but-usable-oscilloscope.
In this earlier post you mentioned:
"I am planning to make it an open design - i.e. schematic and firmware (HEX file and C source code) as well as the PC program freely available, so anybody can build his/her own. I estimate total component cost to be US$10 - US$30 for a one-off built on a stipboard, depending on what you already have in your drawer and what options you want (e.g. BNC connectors or none, and external power supply vs. 9V battery)."
All of the recent posts relate to the hardware but no mention of the PC software which leads to my following questions"
1. What is the PC software programmed in e.g. Visual Basic, C or similar?
2. Could the software be used / adapted to be used directly with a PicAxe as the source of data, I expect at a slower data rate?
3. Is the PC source code available?
One of my interests would be in just using the PC software as a GUI for a picaxe.
Regards
http://www.picaxeforum.co.uk/showthread.php?15814-Interest-in-very-simple-but-usable-oscilloscope.
In this earlier post you mentioned:
"I am planning to make it an open design - i.e. schematic and firmware (HEX file and C source code) as well as the PC program freely available, so anybody can build his/her own. I estimate total component cost to be US$10 - US$30 for a one-off built on a stipboard, depending on what you already have in your drawer and what options you want (e.g. BNC connectors or none, and external power supply vs. 9V battery)."
All of the recent posts relate to the hardware but no mention of the PC software which leads to my following questions"
1. What is the PC software programmed in e.g. Visual Basic, C or similar?
2. Could the software be used / adapted to be used directly with a PicAxe as the source of data, I expect at a slower data rate?
3. Is the PC source code available?
One of my interests would be in just using the PC software as a GUI for a picaxe.
Regards
1. What is the PC software programmed in e.g. Visual Basic, C or similar?
It is written in VB6 Professional.
2. Could the software be used / adapted to be used directly with a PicAxe as the source of data, I expect at a slower data rate?
Directly used - no. That's because the instrument must be a USB HID device. None of the Picaxes can do that, and the USB converter chip solutions typically implement CDC (virtual COM port) rather than HID. The scope functions may be a stretch as well just from the processing requirements etc., except for unusably low sample rates; but the datalogger mode per se should be perfectly doable on a Picaxe, it does not require a lot of computing power on the Picaxe side.
A better bet may be the software of the original DPScope, since this uses a virtual COM port (although I'd need to reduce the data rate from the current 500 kbaud to e.g. 19200 baud). On my website you find a "manual connect" version (i.e. does not expect a specific USB VID/PID for the instrument), you can use that with any device (must support 500 kbaud) on any COM port. The DPScope user manual (second half of it) has all the command descriptions, you will only need a subset though.
3. Is the PC source code available?
No, not at the moment. If there is enough demand I could cut a "datalogger only" version for the Picaxe crowd - if others are interested please let me know.
It is written in VB6 Professional.
2. Could the software be used / adapted to be used directly with a PicAxe as the source of data, I expect at a slower data rate?
Directly used - no. That's because the instrument must be a USB HID device. None of the Picaxes can do that, and the USB converter chip solutions typically implement CDC (virtual COM port) rather than HID. The scope functions may be a stretch as well just from the processing requirements etc., except for unusably low sample rates; but the datalogger mode per se should be perfectly doable on a Picaxe, it does not require a lot of computing power on the Picaxe side.
A better bet may be the software of the original DPScope, since this uses a virtual COM port (although I'd need to reduce the data rate from the current 500 kbaud to e.g. 19200 baud). On my website you find a "manual connect" version (i.e. does not expect a specific USB VID/PID for the instrument), you can use that with any device (must support 500 kbaud) on any COM port. The DPScope user manual (second half of it) has all the command descriptions, you will only need a subset though.
3. Is the PC source code available?
No, not at the moment. If there is enough demand I could cut a "datalogger only" version for the Picaxe crowd - if others are interested please let me know.
westaust55
Moderator
Recall aeons ago I moved to Win98 for inbuilt USB support. Then Win2000 before XP.
MS KB suggests "some versions" of Win95 had USB support.
See:http://support.microsoft.com/kb/258773
This document seems to suggest that HID drivers existed starting with Win98:
http://www.lvr.com/usbwin.htm
But the Microsoft docs show HID support only for Win2000 and above (but that may be just because they don't care about Win98 anymore?):
http://msdn.microsoft.com/en-us/library/ff538820.aspx
In any case, if someone wants to try it out on some older Windows and tell us the results - please do!
http://www.lvr.com/usbwin.htm
But the Microsoft docs show HID support only for Win2000 and above (but that may be just because they don't care about Win98 anymore?):
http://msdn.microsoft.com/en-us/library/ff538820.aspx
In any case, if someone wants to try it out on some older Windows and tell us the results - please do!
mrburnette
Senior Member
There were as I remember, 3 versions of Windows 95:
Win 95
Win 95A
Win 95B (OSR2)
Only OSR2/95B had USB support embedded in the OS. For all versions, many USB manufacturers provided their own USB support, this was often with USB CD-ROM players or CD-RW units which were external. "USB support" was version 1.0, so with newer software, it will be interesting to see how well the hardware downgrades to 1.0 compatible generic driver... assuming that plug-n-play can even find a match.
- Ray
Win 95
Win 95A
Win 95B (OSR2)
Only OSR2/95B had USB support embedded in the OS. For all versions, many USB manufacturers provided their own USB support, this was often with USB CD-ROM players or CD-RW units which were external. "USB support" was version 1.0, so with newer software, it will be interesting to see how well the hardware downgrades to 1.0 compatible generic driver... assuming that plug-n-play can even find a match.
- Ray
premelec
Senior Member
I looked at 2 old units I have an IBM and TI - Win 95 & Win98 - I think the main problem that was ameliorated with XP was needing special drivers for each device - It's probably not worth womai's time to try to write such drivers for his device... however I'm not directly familiar with what that all entails... Thanks for all the info!
Finished the assembly guide today. Also got the missing capacitors and completed the kits with them. Note: The first batch of kits will contain both 22pF and24pF capacitors for C12 and C14 (part of the input compensation network). Originally I thought 24pF would be required, but it turns out 22pF worked better, at least on the two units I built up so far. So I'd recommend starting out with 22pF (this value is also what is in the assembly guide), and don't get confused by the "extra" parts. I didn't want to pull them from the almost completed kits. If necessary (or if you are in the mood for experiments) try one of each on CH1 and CH2, respectively, and tell me the outcome. That will help to pick the best value for the future.
Hopefully I can put everything online over the weekend. I'll keep you posted.
Hopefully I can put everything online over the weekend. I'll keep you posted.
The DPScope SE webpage is largely up and running, kits are available now! Looking back I can't believe it has been a year and a half since I started this project! (back then a single-channel thing based on an 8-pin PIC12F683 and RS-232 connection - how things have evolved...)
The webpage is here:
http://www.dpscope.com
or head directly to the software and documentation (assembly guide is complete, but user manual will follow in a few days. Pictures aren't there yet either):
http://www.dpscope.com/downloads_se.html
I'll open a new forum thread as this one is getting a bit too long for my taste.
Enjoy!
Wolfgang
PS: Sitebuilder gives me some grief, quite often the top navigation bars on my modified site get messed up with duplicate/wrong labels etc. Let me know if you experience the same. Does not seem to be a browser issue as IE and Firefox suffer similar problems... but too late to spend a few more hours fixing that today.
The webpage is here:
http://www.dpscope.com
or head directly to the software and documentation (assembly guide is complete, but user manual will follow in a few days. Pictures aren't there yet either):
http://www.dpscope.com/downloads_se.html
I'll open a new forum thread as this one is getting a bit too long for my taste.
Enjoy!
Wolfgang
PS: Sitebuilder gives me some grief, quite often the top navigation bars on my modified site get messed up with duplicate/wrong labels etc. Let me know if you experience the same. Does not seem to be a browser issue as IE and Firefox suffer similar problems... but too late to spend a few more hours fixing that today.
YES PLEASE Wolfgang I'm sure a "datalogger only" version would be appreciated by the community.
Regards
Late Christmas.
Attached is a stripped-down version of the original DPScope software with manual connect - datalogger mode only. It still works with the DPScope (not the DPScope SE). Includes full source code (VB6) and a compiled EXE. To use it with the Picaxe you need to implement a couple of short commands (see startup.bas) and probably reduce the RS-232 data rate to something reasonable (e.g. 9600 baud).Just hope somebody actually uses it...
Wolfgang
View attachment Datalogger.zip
I just ordered an assembled and tested scope and the BNC to micrograbber probes. Perhaps I just missed it but I couldn't see any method for ordering both the scope and the probes at the same time so I ordered them separately. Maybe there needs to be an "add to cart" feature.
I really look forward to receiving your creation. Thanks, Wofgang, for taking the time to make it.
I really look forward to receiving your creation. Thanks, Wofgang, for taking the time to make it.
Yeah, I'm sure the cart itself is fine. It just didn't work in my site. I'm using Yahoo Sitebuilder and this wasn't the only thing that it seems to get wrong (see the trouble I had just recently with the DPScope SE website). I'll look into it once more when the more urgent stuff (software, documentation) is done - thanks for offering your help for that! I'm also considering a port of my DPScope and DPScope SE software to VB.NET (Visual Basic 2008 or 2010); unfortunately it uses some low-leve stuff that did not quite convert when I ran it through the VB2008 converter. So this will be a major task...