Commit 30953de4 authored by Árni Björnsson's avatar Árni Björnsson
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Measured current in week11

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- [x] Add an output device to a microcontroller I make and program it to do something.
- [ ] Measure the power consumption of an output device.
- [x] Measure the power consumption of an output device.
## What to do
......@@ -613,6 +613,56 @@ Next step was obvious, attaching the laser module to the servo arm!
<iframe width="560" height="315" src="https://www.youtube.com/embed/Bh7bYNAHXxw" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
### Measuring current
Final thing to do is to measure the current usage. You can do that by severing the power supply and connecting a multimeter in serial, passing the current through it, described below:
<figure markdown>
![](../images/week11/curr00.jpg)
<figcaption>Diagram for current measuring</figcaption>
</figure>
Notice the connections on the bottom, the setting which the selection wheel is set on and the MIN MAX button. The MIN MAX button is very handy, since in this case, the servo is only active for a rather short time, we can set it to the MAX and it captures displays the highest load value captured.
I decided to measure the power usage of the servo, since I figured it would be the highest currant using device. I accidentally cut both the negative and positive wires, so I just measured both, there was no difference. But normally you should position the multimeter before the load (servo, light, or whatever you are measuring).
You must also connect the leads to the multimeter correctly. The red one, positive, should go into the A(ampere) slot and the black, negative, should go into the COM port as usual.
<figure markdown>
![](../images/week11/curr03.jpg)
<figcaption>Multimeter connection</figcaption>
</figure>
You then connect the load, making sure to make the positive lead face the supply and the negative face the load, this gives you the correct output.
<figure markdown>
![](../images/week11/curr04.jpg)
<figcaption>Connecting the load</figcaption>
</figure>
Running the code, which just moves the servo and waits for second before moving it again, we get the measurement: ~0.2 A
<figure markdown>
![](../images/week11/curr01.jpg)
<figcaption>Measuring</figcaption>
</figure>
Two little ladies followed my every step, very interested!
<figure markdown>
![](../images/week11/curr02.jpg)
<figcaption>Filmed in front of a LIVE audience!</figcaption>
</figure>
I then added more load the servo, by holding the servo back with my fingers, creating more resistance. This tripled the current consumption!
<figure markdown>
![](../images/week11/curr05.jpg)
<figcaption>Tripled!</figcaption>
</figure>
Wonderful!
## Conclusion and troubles
I made a couple of small mistakes this week, but nothing big.
......@@ -625,8 +675,4 @@ I had some troubles with the software libraries, from what I can see is that the
### Biggest trouble
I caught the seasonal influenza and I've been pretty much knocked out for the last days.
TODO: Measure the power consumption of a output device. I'm confident that I can do that quickly once I regain health and gain access to the lab.
So long for now!
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I caught the seasonal influenza and I've been pretty much knocked out for the last days.
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