I'm trying to analyse ping-response time of US-026 ultrasonic module.
CH1, connected to a pin of the TX transducer, gives the following trace: (a.c coupled simply because that's the way my AD2 arrived)
This trace exacly matches specification (ping = 8 cycles at 40KHz)
CH2 connected to a pin of the RX transducer, gives the following trace: This trace also looks reasonable to me (8 full cycles of echo followed by decaying ringing)
There is some disappointing crosstalk evident with CH1, but this may be down to my wiring.
(CH2 is also a.c coupled according to the board link. Not sure why this trace resembles DC coupling but it's not my primary concern right now)
The US-026 is being operated by arduino in continuous loop, reliably measuring echo time a little over 2000uS - About right, by my calculations, for the 684mm round trip. There is some jitter/noise but otherwise reliable with no timeouts.
However I cannot capture both events using Analog Discovery 2.
I can trigger reliably on CH1 Ping:
I can trigger reliably on CH2 Echo:
The only differences between the latter two above are:
trigger channel
trigger level
x-position (adjusted to show +/- 2mS, as appliccable)
But neither screen captures the corresponding echo/ping, which should be at about +/- 2mS.
This remains true seemingly whatever I set the timebase to. I'm fully braced for this being my fault, I just can't see what I'm doing wrong. I'd be grateful if anyone can suggest what's wrong.
P.S. Two other observations may or may not provide a clue:
1. The echo signal seems somewhat stronger than the ping, counter to my intuition. However I guess it may simply be due to the way the US-026 works?
2. Full disclosure: The probes were set to x10, but the software was set to x1. I presume they should match? However, changing the software to x10 just seems to change trace amplitude which, in my simplistic way, is all I'd expect.
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thegecko
I'm trying to analyse ping-response time of US-026 ultrasonic module.
CH1, connected to a pin of the TX transducer, gives the following trace:
(a.c coupled simply because that's the way my AD2 arrived)
This trace exacly matches specification (ping = 8 cycles at 40KHz)
CH2 connected to a pin of the RX transducer, gives the following trace:
This trace also looks reasonable to me (8 full cycles of echo followed by decaying ringing)
There is some disappointing crosstalk evident with CH1, but this may be down to my wiring.
(CH2 is also a.c coupled according to the board link. Not sure why this trace resembles DC coupling but it's not my primary concern right now)
The US-026 is being operated by arduino in continuous loop, reliably measuring echo time a little over 2000uS - About right, by my calculations, for the 684mm round trip. There is some jitter/noise but otherwise reliable with no timeouts.
However I cannot capture both events using Analog Discovery 2.
I can trigger reliably on CH1 Ping:
I can trigger reliably on CH2 Echo:
The only differences between the latter two above are:
trigger channel
trigger level
x-position (adjusted to show +/- 2mS, as appliccable)
But neither screen captures the corresponding echo/ping, which should be at about +/- 2mS.
This remains true seemingly whatever I set the timebase to. I'm fully braced for this being my fault, I just can't see what I'm doing wrong. I'd be grateful if anyone can suggest what's wrong.
P.S. Two other observations may or may not provide a clue:
1. The echo signal seems somewhat stronger than the ping, counter to my intuition. However I guess it may simply be due to the way the US-026 works?
2. Full disclosure: The probes were set to x10, but the software was set to x1. I presume they should match? However, changing the software to x10 just seems to change trace amplitude which, in my simplistic way, is all I'd expect.
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