PCB scope - a present from Santa?

Technical

Technical Support
Staff member
We are pleased to announce our low cost oscilloscope/logic analyser, specifically designed for those who think they can't afford an oscilloscope/logic analyser!

Based on the successful DPscope design by Wolfgang Maichen, the aim of the PCBscope is to make the lowest possible cost oscilloscope/logic analyser (£9.99+VAT).
PCBscope is ideal for use with PICAXE projects, both within education classrooms and hobbyist sheds!

Maybe one for the Xmas wish list?

http://www.picaxe.com/Hardware/Add-on-Modules/PCB-scope/
 

oracacle

Senior Member
I have been thinking about scopes as of late, this may well have been on the xmas list, if i celebrated it - alas i do not

but at that price i shoule be able to afford it in the new year when i get paid any rate
 

ZOR

Senior Member
Just ordered mine, thank you.
Now I will see whats there, I won't have to guess anymore because I should see whats there or not. Can't wait to build it into a case.
 
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Buzby

Senior Member
Ordered !.

First job, drill two holes after -4- for an extra two pins on the breadboard header.
Then solder a jumper from there to the +5v pin on the USB.

This way I can power and monitor my breadboard using just a single cable.

Thanks,

Buzby
 

Technical

Technical Support
Staff member
As it is an economy device, it is actually designed to be used without probes - as others have pointed out proper oscilloscope probes can cost far more than this board does!

The PCB scope is designed to plug straight into a breadboard, so can be connected via normal breadboard wire links. It also has a parallel straight 0.1" molex style header so that jumper wires can also be used. If you wish to use conventional probes they would also need to be connected to this header.
 

BeanieBots

Moderator
Certainly looks like very good value for money and a useful tool even for those that already have a good 'scope.
A quick browse of the documentation gave input voltage range but only hinted at bandwidth.

What is the bandwidth and what is the resolution?
 

BeanieBots

Moderator
OOPs.. and I'm the first to say RTFM!
A very respectable spec for the price. Comparable to other products costing ten times as much.
 

the old fart

Senior Member
2 X 100MHZ Mini Pro High Voltage Oscilloscope Probes

£7.59 from ebay

free postage.

tried these myself, perfectly good for the hobbiest.
 

womai

Senior Member
Hello, scope designer speaking :)

To answer some of the questions:

The design is functionally identical to the DPScope SE (not the DPScope). Both use exactly the same software as a result. There are a couple of very long threads on this forum from about 2-3 years ago when I developed the original version, for anyone interested in the scope's history.

Full specifications are on the product page (Specification tab below the pictures).

For probes, simple wires are usually sufficient, although the scope will accept standard scope probes as well (you'll need to build yourself a suitable converter for the BNC connectors). With such probes set to 1:10 you can extend the voltage range by a factor of 10 upwards, although in a hobby/breadboard environment I would strongly discourage playing with voltages exceeding 25V! Additional note, due to the way the input stage is designed (the input divider does not go down to 0V but "sits" at an offset) you will need to adjust the offset trimmer when changing from 1:1 to 1:10.

As to the comment about feeding out the USB supply to the breadboard, I deliberately did not provide the USB 5V supply on the pin header; way too easy to accidentally make a wrong connection and short out the USB port. Although any decent USB port will be protected against short circuit this it will still produce a nasty warning and the port will be shut down... so feel free to modify the board any way you like but do not blame the scope in case things go wrong! :)

Any further questions - feel free to ask and I will do my best to answer them. I'd also be highly interested what people are using the little critter for!
 
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Buzby

Senior Member
... As to the comment about feeding out the USB supply to the breadboard, I deliberately did not provide the USB 5V supply on the pin header ...
Hi Womai,

I am very impressed with the 'scopes you have produced. Unfortunately I spent a lot more than £9.99 on a similar product with an on-board OLED, but it's a right b**ger to use !. It's one redeeming factor is that I can power my 5v/3.3v circuits from it.

So when I make the USB-to-header mod I won't blame you if I make a mistake !!!.

What would be really cool, but I've no idea how to do it, would be to run the 'scope, the breadboard, and PE6.1 from a single USB port.

Maybe Rev-Ed missed a trick there :)

Well done,

Buzby
 

Svejk

Senior Member
As a suggestion, integrating the PCB Scope in PE6 would certainly add value to both. Just imagine to have the scope as one of the docked windows when one debugs a piece of software.
 

MFB

Senior Member
Great idea to have designed this interface to plug directly into a prototyping board. Easy to attach to test points and the short wires and associated load capacitance avoids the need for attenuating probes. Unless of course you want to measure more than the 3-5 volts that will be powering most prototyping boards.

At this price its worth considering including a compatible header on pcb designs just for debugging!
 

ZOR

Senior Member
Thanks for the Ebay suggestion for a probe. I think I will get one and stick a bnc connector on the case I'm putting the scope into. Going to connect it to my laptop so my main pc is free for the editor.
 

womai

Senior Member
Here are some instructions for building your own probes:

http://www.instructables.com/id/Oscilloscope-Probes/
http://www.instructables.com/id/DIY-Oscilloscope-Leads-I-made-it-at-TechShop/

and a divider probe:
http://www.instructables.com/id/How-to-make-an-Arduino-oscilloscope-probe/
This one admittedly has its flaws because it does not work as a regular 1:10 probe; for such a probe, a 9 MOhm resistor parallel to a trimmer capacitor (about 1...10pF adjustment range) would be the right choice.

Obviously with the breadboard version of the DPScope there is no need for fancy BNC connectors, further cutting cost.
 

the old fart

Senior Member
Well it arrived, quick delivery.

plugged a micro B usb lead into the onboard socket, a little tight, and the socket parted from the board.

Bu**er.

Flimsy at best.

the socket shown on the pcb picture has been replaced with a smaller insecure type.
 
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womai

Senior Member
Sorry to hear about the mishap.

The current version has indeed a different connector, namely micro USB (same as on many cell phones, portable hard drives etc.). The idea being that most people will have such cables already lying around at home. The picture still shows the preliminary version which has a min USB connector. The change was made because mini USB nowadays is depreciated (replaced by micro USB in 2007) and very few recent electronic devices include them, hence less of a chance to have one around.

http://en.wikipedia.org/wiki/Micro_usb#Mini_and_Micro_connectors

Interestingly enough micro USB is generally touted as more reliable than mini USB (also see the Wikipedia link above). That said, both types of sockets normally come as surface mount components so then to adhere less strongly to a PCB board than old-style through-hole parts.
 

the old fart

Senior Member
the original shows 4 fixing pads, new one has 2.

With a cable attched I can see them parting from the pcb.

Not everyone will be working in a clutter free enviroment.
 

Hemi345

Senior Member
Micro USB connectors are available in through hole and stronger (more ground tabs) SMT mid-mount/drop-in style. I wish they were used more often on tools such as this. Maybe in v1.2!
 

womai

Senior Member
Interesting input. Mid-mount does not see to be any sturdier than regular SMT, but rather just intended to save space (making the assembled board thinner). Some of the vertical mount through-hole jacks do seem to be stronger though. These may have to be user-installed though - adding just a single through-hole component to an otherwise all-SMT design would make the assembly cost skyrocket because it requires an additional - and even worse: manual - assembly step...
 

Hemi345

Senior Member
Interesting input. Mid-mount does not see to be any sturdier than regular SMT, but rather just intended to save space (making the assembled board thinner). Some of the vertical mount through-hole jacks do seem to be stronger though. These may have to be user-installed though - adding just a single through-hole component to an otherwise all-SMT design would make the assembly cost skyrocket because it requires an additional - and even worse: manual - assembly step...
It appears there might be room for both if the SMT was moved over a bit... that would be a nice addition to include the TH footprint next to the regular one for those that wish to add the stronger connection themselves or an option if they happen to lift a pad on the existing one. Maybe even include a header for the USB's 5V line for those that wish to customize it, like Buzby :)

I used the TH part on a project since I could pour a ground plane on the backside of the board to add strength to the shield holes but this was a one off project... just me and my soldering iron. ;) I contemplated using the mid-mount part since it seems like a sturdier design over the regular SMT one. It has the shield tabs at the front AND back of the connector rather than relying on the tiny data and power pads to hold the back of the connector to the board.
 

ZOR

Senior Member
The PCB has four holes in the headers marked 1,2,3,4. Does anyone know what they are?

Having not put mine together yet, I just hope my Micro USB connector does not part from the board. If it does what do we do, as there has been no added thread comment to the earlier one that parted company #28
 
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John West

Senior Member
The forum is here so we don't have to RTFM? Oh, good! :)

womai, have the data grabber bugs been fixed in the code for the new scope? If so, can it be implemented in the original DPscopeSE?
 
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