The project has been finished but there is some optimizations. I have almost ran out of the IO pins of the stm32 bluepill board. Now i have an idea that to determine the state of seven segments we don’t have to use all of the 7 pins of a segment. If we omit the c and d segments, we can…
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Now comes the trickiest part, to capture the pulse with a STM32 blue pill board and send it to computer via serial. I will use arduino for programming. The pinout I have found for the particular PCB board of my multimeter is as following.
Leave a CommentTo determine the segment pins, i had to remember the theory of seven segment. Seven segments usually has 7 LED for showing a single digit and one led for a dot(i dont care for it now). 7 pins to drive the segment 1 pin to drive the dot and one common anode or cathode. The LCD has 29 pins to be analyzed. It has 3 full functional digit and a semi segment to show only number 1. So it should need 7×3=21 pins for 3 digit and 2 pins for the last 1.
Leave a CommentThe mighty DT830D multimeter.
After opened, the meter looks like this.
The LCD pads has 31 pins. Among those, 3 pins are shorted so making 29 pins. If i have to determine signal from 29 pins, an arduino uno will not be capable because it has only 20 useful pins and among those, 2 pins is reserved for serial txd and rxd.
1 CommentTo read the data from a multimeter, at first i have to determine the individual pins of LCD, which is connected to which segment, the microcontroller voltage to drive the LCD and the nature of the pulse. I have opened the pcb from the multimeter and marked the pins that are going to the LCD. Then I have attached a…
Leave a CommentI was fascinated of getting data to PC to conditionally control other things, or making graphs to make the thing more understandable. There are RS232 capable, even bluetooth capable multimeter are available but those costs a fortune for hobbyists. Let’s assume, every hobbyists have enough time (to tinker with things) than money. I have researched on the internet, and found…
Leave a CommentI’ve been inspired by spokepov LED display from ladyada. The term POV means persistence of vision. The hardware and software used by ladyada is opened to all. Everyone can download those files, make it according to their instructions and burn it with the firmwares. It is like DIY – Do It Yourself. But I have some limitations. My bike is…
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