Summary of DIY – USB OSCILLOSCOPE IN A MATCHBOX
This project describes a cheap, truly DIY USB digital-storage oscilloscope (two-channel) built in a matchbox, aimed at students and hobbyists. It provides full source code (C, VB.Net, Python), runs via USB Virtual COM at 115200 bps, supports various sampling rates and trigger modes, includes DFT and XY displays, and can save data/figures; total parts cost claimed $15.
Parts used in the DIY-USB OSCILLOSCOPE:
- dsPIC30F2020 microcontroller (firmware .Hex provided)
- USB connector / USB interface (for +5V and data)
- Input connectors (3 mm audio jacks)
- Analog front-end components (resistors, capacitors for gain settings 1/2/5)
- Input impedance network (1 MΩ resistor)
- Analog bandwidth components (filters for specified band limits)
- Power decoupling components (for USB 5V, 150 mA)
- Passive components for offset control (resistors, potentiometers)
- PCB or perfboard and enclosure (matchbox form factor)
- Cabling and headers
I present a “BEST OF CLASS”, “Full-Featured” DIY-USB OSCILLOSCOPE which is “Truly DIY”.
My aim is to provide a cheap Digital-Storage-Oscilloscope for Students, Budding Engineers and the Hobbyist.
This USB-Oscilloscope could be part of the laboratory equipment in educational establishments.
Build this DIY-Oscilloscope for just $15
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Today 21 Nov 2014, my Instructable crossed 100000 Views!
At this Milestone I am happy to share all the source files (C, .Net & Python) at:
https://github.com/ajoyraman/USB_Matchbox_Scope
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I wish to acknowledge the inputs from the following designs which have led to this optimized solution:
DPScope SE – the simplest real oscilloscope/logic analyzer on the planet, by womai, http://www.instructables.com/id/DPScope-SE-the-si…
DPScope – Build Your Own USB/PC-Based Oscilloscope,by womai
http://www.instructables.com/id/DPScope-Build-You…
LCS-1M – A Full-Featured, Low-Cost Hobby Oscilloscope,by womai
http://www.instructables.com/id/LCS-1M-A-Full-Fea…
PC SOUND-CARD SCOPE INTERFACE FACILITATES DC RESTORATION, by me
http://www.instructables.com/id/PC-SOUND-CARD-SCO…
Universal Analog Hardware Testbench, by me
http://www.instructables.com/id/Universal-Analog-…
Analog Experiments Anywhere,by me
http://www.instructables.com/id/Analog-Experiment…
Two-Channel PC Based Oscilloscope USB, by Gaurav Chaudhary
http://www.circuitvalley.com/2011/07/two-channel-…
Responding to comments and suggestions from many members :
I am sharing the micro-controller fuse .Hex file for the dsPIC30F2020.
The Host PC software has been written in both ‘Visual Basic.Net’ and open source ‘Python’ providing a cross-platform GUI based solution for both Windows and Linux platforms.
Step 1: Specifications
Analog bandwidth (Small Signal), 12/6/7 MHz ,For Gain 1/2/5
Input impedance 1 Meg Ohm
Input connection 3 mm Audio Jack
+6.25V to – 6.25V, Gain 2
+2.50V to -2.50V, Gain 5
-6.25V to +13.75V, Gain 2
-2.50V to +17.50V, Gain 5
Sampling Rate
10bps to 500 kbps, 100ms/sample to 2uses/sample , Normal Mode
Trigger
Trigger Polarity
Trigger Range
+6.25V to – 6.25V, Gain 2
+2.50V to -2.50V, Gain 5
Display Modes
Ch1 vs. time 200 Samples
Ch2 vs. time 200 Samples
XY Ch1 + Ch2 vs. time 200 Samples each
DFT Ch1 400 Samples
DFT Ch2 400 Samples
Capture Modes
Save Modes
PC Software
Power Supply
- How many channels does the DIY-USB OSCILLOSCOPE have?
Two channels. - Can the project run from USB power?
Yes, it is powered from USB +5V and draws about 150 mA. - What input connector is used for the oscilloscope channels?
3 mm audio jack input connectors are used. - What is the input impedance of the scope?
The input impedance is 1 Meg Ohm. - What sampling rates are supported?
Sampling ranges include 1 Mbps to 20 Mbps in ETS mode and 10 bps to 500 kbps in Normal mode. - What vertical scales are available?
Vertical scales: Gain 1 = ±12.5V, Gain 2 = ±6.25V, Gain 5 = ±2.50V. - What trigger modes are available?
Trigger modes include Ch1, Ch2, and Auto with rising or falling edge polarity. - What display and analysis modes does the PC software provide?
Displays include Ch1+Ch2 vs time, single channel vs time, XY mode, and DFT (400 samples) for each channel. - What software platforms are supported for the host PC?
Host PC software is provided in VB.Net 2.0 and Python 2.6/2.7 for Windows and Linux via a Virtual COM port at 115200 bps. - Can captured data be saved and exported?
Yes, data can be saved to CSV and figures to multiple formats.
