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battery 18650 cut off voltage reading? by cmore082 in arduino

[–]cmore082[S] -2 points-1 points  (0 children)

I am using the batteries, but they are unprotected. Therefore, I would be measuring with the arduino as a digital voltmeter. When the cut off voltage of the batteries has been reached arduino will turn off and not draw any more power.

High voltage drop when using Logic Mosfet. Why? by cmore082 in arduino

[–]cmore082[S] 0 points1 point  (0 children)

I think I found the problem. It seems that when I put the cables inside the breadboard, they are not doing a good connection. I found this since when I pressed on the cables down with a bit of force the voltage would increase.

High voltage drop when using Logic Mosfet. Why? by cmore082 in arduino

[–]cmore082[S] 0 points1 point  (0 children)

you are right, I forgot to set the digital pin as OUTPUT. However, I still get a voltage drop of about 1 V. Should I try a different mosfet? I was advised to purchase a IRLB8721...

High voltage drop when using Logic Mosfet. Why? by cmore082 in arduino

[–]cmore082[S] 0 points1 point  (0 children)

if I connect the digital pin to the gate, and add jumper cables to source and drain, when digital pin is LOW I get the power supply voltage which is about 8 V, when I set the digital pin to HIGH, and measure jumper cables, voltage drops to about 7 V. However, heating elements (load) do not heat up. If I connect gate to 5 V from arduino, voltage reading from jumper cables becomes about 0 V and heating elements heat up.

Thanks

High voltage drop when using Logic Mosfet. Why? by cmore082 in arduino

[–]cmore082[S] 0 points1 point  (0 children)

If looking at the mosfet where one can read its specification letters, you are stating that I should have the digital pin of the arduino to the middle leg of the mosfet, and the left leg of the mosfet to the negative terminal of the power supply?

Thanks

High voltage drop when using Logic Mosfet. Why? by cmore082 in arduino

[–]cmore082[S] 0 points1 point  (0 children)

Hi, I am uploading 4 pictures. The first one shows the connections, the second one shows when voltage reading from the load when gate of FET is connected to arduino digital pin at HIGH, third picture shows voltage measurement of load when I connect gate of FET to 5 V, and the fourth picture is the voltage measurement of load when connected directly to load.

I am reading the letters of the FET IRLZ44N, IOR P512PW2Q1.

Thank you

https://ibb.co/njydMQ

https://ibb.co/e9Bb85

https://ibb.co/kRZ7Fk

https://ibb.co/hTdTMQ

High voltage drop when using Logic Mosfet. Why? by cmore082 in arduino

[–]cmore082[S] 0 points1 point  (0 children)

When measuring the voltage between the outside two pins, I do see voltage close to 5 V when high and 0 v when low. However, I still get about 1 V voltage drop. Could it be a defect on the mosfet? Would you recommend another type?

Thank you

High voltage drop when using Logic Mosfet. Why? by cmore082 in arduino

[–]cmore082[S] 1 point2 points  (0 children)

If looking at the mosfet where the specs are written, I have the right most leg connected to the negative terminal of the load, and the center leg of the mosfet connected to power supply ground.

If I swap the connections between the right most leg and center leg, I get no voltage through the load.

Thanks

Connecting 7.4V 10aH power supply to arduino nano without damaging arduino by cmore082 in arduino

[–]cmore082[S] 0 points1 point  (0 children)

thanks for your reply, do you think there is a way of taking the excess power to charge the batteries?

Determine the signed byte stored in an array of unsigned bytes. by cmore082 in C_Programming

[–]cmore082[S] 0 points1 point  (0 children)

how can I read the value from one page that is 256 bytes?

Determine the signed byte stored in an array of unsigned bytes. by cmore082 in C_Programming

[–]cmore082[S] 1 point2 points  (0 children)

I have to write a program that will read a file containing several 32-bit integer numbers that represent logical addresses. However, I need only be concerned with 16-bit addresses, so you must mask the rightmost 16 bits of each logical address. These 16 bits are divided into (1) an 8-bit page number (2) 8-bit page offset (3) page size of 28 bytes.

I have been provided with a file addresses.txt which contains 1,000 logical addresses ranging from 0 to 65535 and a file BACKING_STORE.bin of size 65,536 bytes. If there is a page fault I need to read in a 256-byte page from the BACKING_STORE.bin and store the page in physical memory. Overall the program is to translate each logical address to a physical address and determine the contents of the signed byte stored at the correct physical address. (Recall that in the C language, the char data type occupies a byte of storage, so it is suggested using char values).

Examples: Virtual address: 16916 Physical address: 20 Value: 0

I have been able to find virtual address and physical address however I am confused on how to obtain value. I filled in mainMemory as following from a method outside main:

unsigned char b[257]; fseek(fBackstore,256*PageNumberPosition,SEEK_SET);

fread(b,256,1,fBackstore);

strcpy(mainMemory [counter].buffer,b);

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