Make sure you're not using a resistor to disable auto-reset. It is not needed with newer versions of the client.
Here are some troubleshooting steps:
0. Make sure serial monitor is closed.
- Reset Arduino via hardware button. ( you also unplug / replug if you want)
- Click start capturing button in OLS client.
- Set to correct com port, 115200bps, device type "original sump device" (do NOT click show device metadata)
- Click triggers at the top, make sure they are not enabled.
- Click Acquisition at the top, make sure it is Default, Internal, 500.0kHz, channel groups zero, 1.00kB no test/noise/RLE
- click capture.
- note what happens. if necessary click 'STOP' in OLS client.
- switch to Arduino IDE, open serial monitor, send '1' enter
Someone else with an UNO R3 reported somewhat similar symptoms and he was able to get it working after a bit.
Try adjusting these three settings: (not all at once)
device.open.portdelay = 1500
device.receive.timeout = 100
device.open.portdtr = true
You could try 2000 or 3000 for the portdelay, bump the timeout to 500 and try toggling the portdtr. Exit the client, unplug / replug the UNO, restart the client between settings change.
I would be interested to find out what makes a difference. I have an original UNO (bootloader updated to the rev 0001) but it works fine for me. Since I can't reproduce these R3 problems I might just pick up an UNO R3 to test out. At least if we can't figure out an easy fix.