Hi another ADS1115 question please.
(And it's not on an Arduino but on a Pi Zero 2W thru an HW-660 Pi Hat/Board with an ADS1115 attached. See: https://www.aliexpress.us/item/3256803757799407.html?gatewayAdapt=glo2usa4itemAdapt)
I'm playing with two types of Hall Effect current sensors, a WCS1600 and an ACS712.
All current sensors boards do not have their DC current terminals wired up. They're just reading "nothing".
With an Winson WCS1600 current sensor attached only to Channel 0 (3.3V and Ground attached) I get these readings:
raw v
11774 1.470
11775 1.470
An ADC value of about 11775 and a 1.47V reading.
Then I left the WCS1600 attached and added an ACS712 30A current sensor to Channel 1.
And these are the new readings:
raw 0 v raw 1 v
14170 1.770 6079 0.636
14170 1.770 6059 0.640
14170 1.770 6060 0.640
14170 1.770 6057 0.642
The WCS1600 ADC values and voltages jump up a bit.
Now leave the WCS1600, the ACS712 30A connected and add a WCS712 5A current sensor to Channel 2:
raw 0 v raw 1 v raw 2 v
14169 1.770 6068 0.638 4543 0.586
14170 1.770 6069 0.642 4589 0.566
14170 1.770 6056 0.642 4638 0.574
My question is - could someone explain to this non-EE type why the WCS1600 readings went from 11775 to 14170?
I'm not that concerned about this, I'm just curious as to why the value would jump up?
Again, there's no DC current flowing thru the sensors, they're just sitting on my desktop wired to the ACS1115.
thanks!
Sorry, but there isn’t enough information for me to properly answer your question. Please post an annotated schematic showing all connections, including power, ground, and power sources. Be sure to note any wires longer than 10 inches (25 cm) and include details about any filters or other components you’re using. Additionally, posting a clear picture of your setup would be very helpful.
Why do I ask?
- Analog is Continuous Signals:
- Unlike digital, which deals with discrete values (0s and 1s), analog involves continuous signals that can take on an infinite range of values.
- Precision and accuracy are key, which can complicate design and troubleshooting.
- Analog Has Noise and Interference:
- Analog signals are susceptible to noise and interference, requiring careful design techniques like filtering and shielding to ensure reliability.
- Count on Component Variability:
- Analog components (e.g., resistors, capacitors, op-amps) often have tolerances that can affect performance. Understanding these variations and compensating for them is critical.
- Mathematics can get involved:
- Analog design often requires a solid understanding of circuit theory, including Ohm’s Law, Kirchhoff’s Laws, and concepts like impedance, gain, and frequency response.
- Measurement and Accurcy Challenges:
- Observing and debugging analog circuits often requires specialized tools like oscilloscopes and spectrum analyzers.
Thank you for the detailed reply! I'm just a tinkerer, so I never made a schematic. I just hooked up the wires and ran some code to see what would happen. You gave me several ideas/reasons as to why the values could change. Thank you.
It did occur to me last night that I should see if the results I got are repeatable and if I can vary them by physically changing some of the connections.
None of the dupont wires are over 10", at worst they're 8". I have added no add'n components. Just using this inexpensive ADC board for the RPi.
In the end, it's largely immaterial to me, I can adjust my code to accommodate (if the results are repeatable). I was more curious about whether this was a common occurrence when dealing with outboard ADC hardware, or more perhaps due to this inexpensive board. And was looking to see if others have seen similar things.
Thanks!
I would expect so. The more bits the A/D converter has, the more sensitive it becomes. To estimate its sensitivity, divide the full input voltage range of the A/D by the number of steps (resolution). This will give you an idea of how finely it can detect changes in your signal. However, keep in mind that this increased sensitivity also makes it more susceptible to noise, which can impact your readings.