Looking for circuit design feedback (UNO, Two Servos, Proximity Sensor and LEDs)

Hello — new to the forums and fairly new Arduino.

I’m working on a circuit design for a project and would really appreciate some guidance or thought on the circuit layout — does it appear correct? Most importantly, the power and capacitor layout and any need for resistors? Attached is a fritzing diagram.

Thank you!

Your power and grounds are not right. The grounds on the capacitors are right, but you're straight shorting your power supply and hooking up your peripherals backwards.

Updated images.

Thank you for the quick response! I did see that my ground from arduino was wrong — I updated that.

I also removed that dc barrel jack to indicate just +/- going into the bread board.

Can you explain '...hooking up your peripherals backwards' ?

Thanks!

It just meant the other parts that aren't the arduino. It actually looks like the only thing hooked up backwards is the ultrasonic sensor.

I'm assuming the digital pins are correct.

Aha, yes, thank you, fixed the image again — the pins on the LED strip are wired to match what I have currently.

On the Fritzing: "The arduino will be powered via the one 5V 3A power source through it's barrel jack"

Can't do that. The barrel jack needs at least 7volt, for the onboard regulator to make a stable 5volt supply for the MCU. Leo..

Aha - I didn’t know that. Can I just wire a USB cable into the 5V line and power the Arduino that way?

Or, I guess I’d need 7V DC power and then resistors between power and the peripherals? The LEDs should be fine on 7V but that may not be good for the proximity sensors and servos.

Not wise to power the other devices from 7volt. You can connect the 5volt supply directly to the 5volt pin of the Uno, bypassing the onboard regulator.

Disconnect before you connect the USB lead to a computer. The PC might not like backfeeding 5volt into it's USB socket. Leo..

Wawa: Not wise to power the other devices from 7volt. You can connect the 5volt supply directly to the 5volt pin of the Uno, bypassing the onboard regulator.

Disconnect before you connect the USB lead to a computer. The PC might not like backfeeding 5volt into it's USB socket. Leo..

I see — I just need to be darned sure my power supply is regulated, correct? And if I were to power it this way, I'd have power into the 5V pin, and ground into one of the ground pins... but would I still need need a separate ground back to the bread board?

Yeah, I'm being cautious when the arduino is connected to the PC and the rest of the circuit is powered by the DC input.

creatify: I see — I just need to be darned sure my power supply is regulated, correct?

Yes, but that also is important for the addressable LEDs. Leo..

Hi, Welcome to the forum.

Please DO NOT keep going back and changing your first post. In doing so you have made the first 6 posts absolutely misleading and confusing.

Each time you update anything PLEASE write a NEW POST. This thread may be used by someone in the future to fix their own problem, it is now basically useless as most of the content has been compromised.

Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png? Use labels on your connections to servos, sonar, and include your power supply, please don't cross wires at angles, only 90deg please.

Sorry but there is no better CAD package for new users like a pen/pencil and paper.

As a beginner the looks of Fritzy look real schmiko, but it does not convey the necessary info needed for proper circuit analysis.

Thanks.. Tom.. :) http://www.urbandictionary.com/define.php?term=schmicko

Thank you for the tips, TomGeorge.

I'm not sure if my hand-drawn circuit will be more legible than what I posted via fritzing, but I'm a big fan of pen/paper. I've attached a sample if this helps others that may see issues — if a hand drawn circuit needs to be more of a standardized 'diagram' I'll have to dig a bit to determine how to modify it. |500x343

Hi, Thank-you, that is much easier to read, just need some pin names on the UNO and some polarity signs on the electrocaps. Also point out the barrel connections, what polarity the inner barrel and the outer sleave of the plug.

Thanks.. Tom.. :)

I'll add as much details as is necessary to get qualified answers! (Versus combing through many different random google findings that only show parts of what I'm looking to do.)

So, I added three power step downs (couldn't I just use one?) to this 'schematic' to ensure I A) have a solid connection of 7.5V into the arduino B) knock the voltage down to accomodate 3/4 peripherals.

Seems like by adding these I'm increasing the potential points failure by quite a bit? Maybe that is a reservation I'll have to make being new building these types of circuits.

I'm really looking for a long term stable design here — I plan to use this exact same circuit on several projects with the only variable being the number of LEDs (which I'll ensure I have enough current to run). I'm decent at soldering and can write the code, but I have a lot of uncertainty and noob in the circuit itself.

|500x375

Servos don't have to be controlled from PWM pins: any pins, including the A0-5 pins, will do.

kenwood120s:
Servos don’t have to be controlled from PWM pins: any pins, including the A0-5 pins, will do.

Thank you for the tip!

The HC-SR04 is low power, and can be powerd from Arduino’s 5volt pin.

The addressable LED strip will fry if you power it with 7.5volt.
If you have <=7.5volt on the DC socket, then the Arduino might also be able to power the LEDs (<=12).
Reducing max LED brightness also reduces average current draw.
Leo…

Wawa:
The HC-SR04 is low power, and can be powerd from Arduino’s 5volt pin.

The addressable LED strip will fry if you power it with 7.5volt.
If you have <=7.5volt on the DC socket, then the Arduino might also be able to power the LEDs (<=12).
Reducing max LED brightness also reduces average current draw.
Leo…

Thank you — I forgot the LEDs were 5V too. If I do need to use 5V, step down — could I use a single 5V step down between the main power source and the 2 servos / LEDs? I’d place capacitors after the step down for each item.

Servos have high stall currents. Better use one buck for each.

As said, the Arduino has an onboard 5volt regulator that can provide 600-800mA if…
voltage on the DC socket is <= 7.5volt.

Will you be running the LEDs at full white (600-700mA) all the time?
Leo…

Thank you, again!

Except for brief moments of a few seconds or so, the LEDs will NOT be constantly on nor at full white or brightness.

All of the peripherals will respond to the proximity sensor though, so there will be a lot of variation in the current draw as visitors near this item and then move away.

I believe the WS2812B LEDs will max out at 60mA on full brightness if my research is correct? — so, even with that I can connect LEDs and the proximity sensors directly from the arduino if I choose to.