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MAX232/MAX3232 heating up – I am using a MAX232 to convert RS232 level to UART TTL Level. It is between a sensor and an Arduino MEGA2560. I have already tried 56K and 120K baud-rates. The problem is that sometimes it works, even for hours without any problems and it remains cool! But if I decide to reset the power, it might not work and it starts heating up. If I let it cool down for a while, there is a good chance it will work the next time. I have used 4 of them from different batches, and the result is the same. Read more
8051 Assembler LCD programming – I’m trying to initialize an LCD and write data to it (displaying characters). I’m using a lot of connections to the desired port and therefore decided to use an electronic chip named 74hc138 which, according to certain code, will address the correct device. I’ve decided to put the LCD on 0x6000. I’m initializing the LCD with the proper commands and send data and burn the program, yet there is only one bar with black boxes. Read more
IR211- circuit for three-phase BLDC motor – I have designed a circuit for driving a three-phase BLDC motor using IR2110. I designed the circuit in a PCB board. To see if the PCB board is working, I interface the normal 12V dc motor with the circuit. I don’t know that this is the proper way for checking the circuit but I wasn’t able to drive the motor. Read more
Stepper motor taking too much current – I am using a unipolar stepper motor by using 4 NMOS chips. Each source is connected to ground and each drain is connected to a corresponding coil and gate from the microcontroller. I don’t know the rated current or voltage of this motor but I measured the coil resistance (common to A pole 2E and A to -A is 4E like in B side also same). When I connected it to the 12V, it heated more and is not rotating but vibrating and the wire burned. Read more
mkroC 4 digits example – I’m new to MikroC and by learning it from examples. I need an example of 4 digits which has 4 variables I can use for 4 digits? Read more
Problem with reading ACD with Arduino using AD7401 – I’m using an Arduino mega to read a 16-bit AD7401. I use it for measure voltage drop on a shunt resistor for measuring current. In the datasheet, -200mV is 12288 and +200mV 53248. So 0V should be 20480 but the values I am reading are strange. Read more
Frequency measurement using input capture module in dsPIC30F5011 – I am using the dsPIC30f011 controller and I configured the input capture module to measure the frequency by capturing every rising edge. But I am getting only KHz frequencies and not getting the frequencies in Hz. What is the reason? Read more
Which MCU should use to convert signal – I want to read a 50Hz singal from an AC transformer (only upper half wave) and use it to generate a square signal. The output square signal should be preferably at the 5V level. The blue signal in this image is the signal that I want to read. The red signal is the signal that I want to generate. Both signals must be synchronized. What is the cheapest and simplest MCU I can use for this purpose? Read more
Programming in C – I’ve learning embedded C with the help of a friend but need some help with my project. I’m using 4, 7-segment digits and sometimes I want to use two of them as a countdown counter and the others for display functions. In the setting mode, I want to use the four together to indicate some functions like “open,PRO1…”. Any example of something similar or any ideas? Read more
IoT device hardware/firmware selection – I am planning to make an IoT device for home access control which should support rich GUI with capacitive touch display and wifi connection. I am also thinking to include a camera for video recording then playing it on the LCD. I have following options for hardware platform in my mind
1 – ARM Cortex M7 – ST or Freescale
2 – ARM A8 i.e. beagle board
I need expert opinion on which hardware platform I should go with. Read more
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