$10 O-Scope revisited

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mausi_mick
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Re: $10 O-Scope revisited

Post by mausi_mick » Wed Apr 05, 2017 3:30 am

ThunderOwl,

now the DLO-138 SPI TFT is nearly ready ( I have to integrate trigger_level for correct triggering).

But I have success with the DDS AD9850/1 with SPI.

Now I need only one extra line for FQ_UD (corresponds to CS ), DATA -> SPI-MOSi, AD_CLK -> SPI-CLK, AD_RST-> Ground.
Here some pictures from the test:
DLO138sSPI_Display_test_AD9850_51_SPI.JPG
DLO138sSPI_Display_test_AD9850_51_SPI.JPG (50.7 KiB) Viewed 1431 times
DLO138-SPI_Display_AD9850_DDS_SPI_1kHz.JPG
DLO138-SPI_Display_AD9850_DDS_SPI_1kHz.JPG (57.46 KiB) Viewed 1431 times
On the left you can see the AD9850 (red led), in the background the DLO-138,
in front a second maple-mini with an SPI-Display (for frequency input) and the AD9850 on SPI.

ag123
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Re: $10 O-Scope revisited

Post by ag123 » Wed Apr 05, 2017 9:51 pm

i'm thinking that eventually as an 'add on' we could integrate an i2s audio
http://www.stm32duino.com/viewtopic.php?t=519
play an mp3 file from the sd card, add an fft for a dancing frequency display)
:lol:

mausi_mick
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Re: $10 O-Scope revisited

Post by mausi_mick » Thu Apr 06, 2017 1:17 pm

sorry, Ihave no PT8211 ?

now I have modified the touch-input for DDS AD9851 to wobble the frequency between start-frequency and stop-frequency.
You can input the frequency-step-width in Hz and the time /step in ms.

The video on youtube:

https://youtu.be/5vU442v46ls

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rexnanet
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Re: $10 O-Scope revisited

Post by rexnanet » Thu Apr 06, 2017 1:21 pm

Nice work :)

I haven't been able to work on this...

Andrew25
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Re: $10 O-Scope revisited

Post by Andrew25 » Mon Apr 10, 2017 7:24 am

Sorry for the question of a beginner. I make an oscilloscope from this topic with two encoders.
Before that, I had only an analog oscilloscope in my life. I have a few questions. What is timebase? How to calculate the signal frequency? What is xzoom?

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ThunderOwl
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Re: $10 O-Scope revisited

Post by ThunderOwl » Mon Apr 10, 2017 7:44 am

Andrew25 wrote:Sorry for the question of a beginner. ... What is timebase?
Hello! I hope I will answer corectly about timebase :)
curently set timebase means that on screen, on horizontal axis, that much time is one screen grid.
Frequency is f = (1 / Period), or, Period = (1 / frequency)
Period is one "positive" and one "negative" halves of periodic signal (everything after that is just repeating of that period).
Soooo.... Suppose we have signal 1MHz. 1 divide to 1000000 we got 1 microsecond.
If ofcilloscope has timebase set to 1us (miscosecond), that means, you will see one full period of signal in one screen grid, horizontaly.
Verticaly - that is about signal apmplitude (volts)
In every man's childhood, first 40 years are the hardest

Andrew25
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Re: $10 O-Scope revisited

Post by Andrew25 » Mon Apr 10, 2017 12:41 pm

IMG_20170410_160223.jpg
IMG_20170410_160223.jpg (145.03 KiB) Viewed 1288 times
How to determine the frequency of the signal, which is in the photo? Can you use this example? Timebase - is the price of one division?
I reason so... The period takes 15 small divisions or 1,875 large. One division is now 100 uS (Timebase)? Then 1.875 * 100 = 187.5uS
1/187.5=0.00533 .Then 0.00533*1000000=5333 Hz

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efftek
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Re: $10 O-Scope revisited

Post by efftek » Mon Apr 17, 2017 10:18 am

I have made a prototype board for my project but it would also suffice for the O-Scope
WP_20170417_10_46_28_Pro.jpg
WP_20170417_10_46_28_Pro.jpg (184.87 KiB) Viewed 1206 times
WP_20170417_10_46_42_Pro.jpg
WP_20170417_10_46_42_Pro.jpg (193.18 KiB) Viewed 1206 times
There is a provision for a 7-12V PSU but here Im powering it simply by connecting a 3.7V LiPo to the 0 and 5V pins. The board has a blue pill soldered on it (underneath the TFT shield - bad idea, V2 will have it on the other side) and takes as you can see, a standard UNO style TFT - in this case 3.95" and it works directly with David Prentice's MCUFRIEND.kbv library. There were supposed to be 6 tactile switches but I changed my mind and just fitted 5 with a slight modification to get it working! There are 2 analog pins left - the others go to the TFT and 4 digital pins left.

V2 will have an on switch which connects the GRD via a MOSFET which is latched by the blue pill and can be turned off via software after a period of inactivity or by selection of a menu option. It will also have protection so that the battery supply and the 5V from the USB dont cause damage but it wont charge the LiPo, thats for my end board which wont feature the blue pill but have the MPU etc on board (when/if I get that far!!!) It also has provision to solder a surface mount SPI EEPROM for data storage.

Once I know its working properly, I'll put the eagle files on my github.

@Andy Hull, I would like to send one of my boards to you so you can play with it and see what you can come up with using a TFT shield rather than a SPI TFT. If you would be interested, please PM me. I'll fit the componants, you just need a screen.

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ThunderOwl
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Re: $10 O-Scope revisited

Post by ThunderOwl » Mon Apr 17, 2017 11:00 am

Wow...
In every man's childhood, first 40 years are the hardest

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efftek
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Re: $10 O-Scope revisited

Post by efftek » Tue Apr 18, 2017 9:49 am

Update ....

The V2 board will have a charging facility for LiPo batteries from the USB. Ive also thought to put a link in to connect the CS to either the EEPROM or the SD card on the TFT shield - all usable pins were used so I cant have a CS for both.

Once I have it made and I know I havent made a booboo, I'll put the eagle files on github.

I'm also thinking about selling a few on eBay ready assembled with EEPROM fitted and the bootloader burned into the blue pill. The cost will be about £25 GBP, maybe less depending on if I can get the parts cheaper in bulk.

Steve

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