so im working on a project for my internship and i feel like im left alone with no profissional help what so ever. im working on Arduino Micro, MPU6050 (acceleration sensor as a fall detector), Max30105, SIM800L and a touch screen.
i finished my schematic and would like to have some insight if it would work, and if any other components needed.
appritiate any advice
I moved your topic to an appropriate forum category @moe1626.
In the future, please take some time to pick the forum category that best suits the subject of your topic. There is an "About the _____ category" topic at the top of each category that explains its purpose.
This is an essential part of responsible forum usage, as explained in the "How to get the best out of this forum" guide. It contains a lot of other useful information. Please read it.
Thanks in advance for your cooperation.
What is it supposed to do? Can you name the function of each block instead of just part numbers? Pretty. Are you making a phone?
Any code? (please post with tags after formatting in the IDE with ctrl-t, tyvm)
You have Vin, +5 and the 7.4V LIPO battery tied together. This will release the magic smoke from your parts.
The +5V from your cpu cannot be used to power the other circuitry.
Your battery is connected to both Vin and 5V. Wrong. Firstly, you must connect that voltage only to Vin. Secondly, the rest of your circuit will be too hungry to be powered by the puny little regulator on the Arduino, so you'll need to source a second 5V supply for your circuit. Alternatively, you can use a "buck converter" to convert 7.4V to 5V and power it all.
That's a start.
Start by putting the pieces together, one by one and learn how each one works before moving on. Arduino and MPU6050 would be a good place to start, and there are plenty of on line tutorials.
The first thing you need to solve with the Arduino Micro (5V) and the MPU6050 (3.3V) is that they have different I/O voltage levels, and you need a 5V to 3.3V logic level shifter between them, or you will destroy one or both of the parts. Same for the SIM800L.
Ignore any tutorial that recommends that you connect these parts without using a logic level shifter, as those tutorials were written by people who have no idea what they are doing.
Sometimes the logic level shifters are built in to a sensor module, but if not, this is a good choice.
Would it be an idea to move to a 3V Arduino?
Many data receiving 5V devices can receive 3V inputs without trouble...
Two level shifters on a breadboard adds a lot of connections that could be bad... (and will give a rat's nest).
As for your schematic: plus should be on top gnd at bottom. Power goes from left to right (battery left). Data go from left to right (sensors left, actuators, motors screen right, cpu in middle).
Try to minimize bends and bridges. Turning max 3xxxx by 180 degrees will give a much clearer picture.
Is this just a proof of concept or a lasting build? interconnects for a quick test are ok, but for something useful, better fab than breadboard is needed.
Breadboard is fine for most basic tests, but you'll need better connections or a pcb depending on anticipated build volume. Just the one, breadboard, 2 to, say, 20, connectors, over 20, pcb's.
its supposed to detect a fall, measure the heartrate and then a warning message with the location.
the code ill upload soon, although im not sure about it, the project is really above my abilities.
so i should lower the voltage to 5V before connecting to the Arduino? or would the arduino onboard regulator be able to do it?
and i would power the rest of the circuit from the battery through an additional voltage regulator (from 7,4V to 5V) because all of my parts can operate at 5v voltage (all have builtin voltage regulator).
thank you for your reply i appritiate it
i have to get the okay first from the University first, the meeting is 27th of april and my graduation depening on it. and then i might do a free style MCU and a PCB
okay so VIN to the voltage. but would the board be ablte to take the 7,4V or should i take that down to 5V through an additional Regulator?
buck converter or a voltage regulator to connect the other parts with the battery?
thank you man and bare with me my low knowledge please
hey man thanks for the reply,
all the parts have an onboard regulator so they can all operate at 5V voltage. im going to connect all parts throught a voltage regulator to the battery, in doing so all the components will powered by a 5V voltage.
i still dont know if i should use a voltage regulator or a level shifter or a buck converter, i understood that the do the same trick?
please excuse my poor knowledge
hey thanks for the advice im thinking of using LiPo 3,7V 1200mah but im not sure if it would be enough, the SIM800l requries a minimum of a stable 1A current to operate correctly.
any advice on how to calculate is the 3,7v liPo is functional?
regarding the schematic, do you mean i should rotate the battery by 90 degree so the plus pole is on top? or i should place the battery also on top?
and then place sensors on the left side and the screen on the right side with the Arduino board in the middle?
cheers and thank you, i appritiate it
You need to look up the max current of your lipo.
Usually that is around 3 times the battery capacity.
1000 mA.hr can usually seliver 3 A max.
All the other questions: yes!
That does not solve the problem of different I/O voltage levels. You still need logic level shifters.
Build one module at a time. Then add them in the code. Small steps are easier to debug than throwing a bunch of parts together and then trying to debug everything at once.
Power with +5V to everything via a separate +5V power supply. Converting the battery to +5 is a separate circuit. Don't use Vin as the onboard regulator dissipates a lot of heat. Powering with +5V on the +5V line works much better.
You need to read the spec sheet of each part and figure the voltage & peak current requirements. Everything needs to be 3V3 or 5V0. Else mixed voltages require level shifters, period.
This is an ambitious task.
There might be a simpler way to detect a fall. A simple tilt switch can tell vertical from horizontal.
I wasted time looking for the data sheets. Its polite to provide links to the parts you are using.
It would make sense to decide initially on the features you NEED and how you will power them, before choosing the parts which in this case dont match as far as supply voltage is concerned.
A separate comment here about drawing schematics.
Conventionally schematics read left to right, inputs to outputs.
Top to bottom is ordered by voltage. Highest at the top, lowest at the bottom. Orient your discrete components toward their voltage source/sink.
Labelling blocks by name (function) in addition to the part numbers is a big help.
Signal flow is left to right, not up and down. Rotate your schematic blocks so you don't have to turn your head to read.
Good schematics are drawn to minimize bends and crossovers.
Device pins don't need to be in order - group by function. Vcc pin at top, gnd at bottom, inputs on left, outputs on right.
Oh, you don't have a nice R/C on the RESET line to the CPU to insure clean reset and prevent false triggering.
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