How to Balance a Circuit?

Other Hardware Sensors
1

Hi,
I have a multi-sensor configuration connected to an Arduino MEGA R3. Please reference the attached Fritzing file.

The code works, but sometimes it seems to stall or hang after a few random loop cycles. I found that if I up the voltage on the buck, it will run longer and without issue. When I checked the voltage at each sensor, using the buck ground and each sensor's voltage in, I can see that some sensors (like DS18B20) had very high voltages (around 5.6 V). This having me think I am going to fry a sensor. When checking the other sensors they seemed to be right at 5 V. The GPS was a little low at 4.8 v. The DS3231 was a little high (5.4 V) and the SD Card Reader was a little low (4.8 V). The WiFi module was also low (4.5 V).

I noticed all fluctuated as the WiFi module sucked in current. So I tried adding the caps in front of each module to se it it helped. It sort of did in that each module now stays around the same voltage, but the smaller ones (DHT11, DS18B20, HS711) are getting upper side of 5.7 V while the WiFi and GPS are at lower range of 4.6 V.

I do not know the best way to even out the current so that the heavy usage modules get closer to 5 V and the smaller current modules come down.

Is there anyone give some ideas and practice approach? :drooling_face:

2

Hi Penny; no-one is going to look up datasheets on theose sensors and parts so you will need to provide links to the parts you actually have connected.

eg I'd guess you are using a module, not this device

And no-one wants to see fritzies. (anyway you forgot to add it)

How to make a schematic you can post.

If the power and ground lines are connected correctly the voltages should all be the same.

(unless some run at 5V and some at 3.3)

3

fritzing does not have any sensor I use. very common sensors like GPSs and sound modules - no luck.

are you using extremely small wire? how can you get an almost 1 volt variation in a project a foot sqare?

4

Is there anyone give some ideas and practice approach?

  • I would re-adjust the buck regulator to 5.0V ASAP.
  • I would re-configure your grounding scheme so that it avoids any ground loops. Run separate ground wires from each device (including the Arduino) back to a common point at the regulator or a single breadboard ground rail.
  • Is there adequate filtering caps at the regulator, breadboard and devices?.Oh, as mentioned, please post a diagram (and also your code might be helpful).
5

It sounds like you're getting a lot of voltage drops across your sensor array. What are you using to connect sensors and how far away are they? Ribbon cable, for example, isn't designed to handle large currents. Wifi and GPS modules can draw a lot of power. How are the connections to the Mega board made?

Are you powering the DS18B20 sensors directly or parasitically?

Please at least post your fritzing diagram. It was not attached to your original post.

S.

6

Far better, do a hand drawn diagram of your circuit and connections and post that, you won't be
limited by Fritzing then.

7

Sorry,
I don't know why I failed upload image, so i enclose the fritzing diagram source which i found: source (removed by moderator due to OP being a spammer)

8

The quality of the fritzy is so poor as to be useless Penny.

You will need to attach the original to your post using the "attachments and other options" you will find left of the "post" button.

I'd also recommend you attach a photo of your layout. Its pretty complicated we will need to see how you are doing it.

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