Comment summary #6
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Comment 51 ... 60
| date | article | author | comment |
| 06 maa 2020 23:09:19 | Arduino wattmeter | Matt | Thank you. :) |
| 06 maa 2020 20:42:01 | Arduino wattmeter | Freddy | @Matt, You can monitor the (dis)charging at the battery as you wishes within the accuracy limits described in the article. To reduce the power consumption yo may remove the LCD. I don't know in how far the power consumption can be reduced. Remember that the ADC has to run continuously to detect spikes. Just experiment with it. Succes! |
| 06 maa 2020 20:26:16 | Arduino wattmeter | Freddy | @Raju, I'm sorry. To convert the code to another system is something to figure it out yourself. I don't have the time for it. Sorry. |
| 06 maa 2020 20:21:34 | Arduino wattmeter | Freddy | @Milli, No, 1024 is correct, that is the number which the reference must be divided by to get the step size. Suppose you have a reference voltage of 4 volt and a 2 bit ADC (4 discrete levels), then each step is 4V/4=1 volt. level 0 = 0.0 till 1.0 level 1 = 1.0 till 2.0 level 2 = 2.0 till 3.0 level 3 = 3.0 till 4.0 |
| 06 maa 2020 19:50:16 | Arduino wattmeter | Milli | "The conversion from the raw ADC-values to the real voltage and current values is done with a scale factor: For voltages this is Vscale = ADCsense * Vdiv, and for current Cscale = ADCsense * Cdiv. ADCsense is the ADC sensitivity: 1.1 V / 1024." 1024 is wrong! Use 1023 and you get a correct conversion! A 10 bit converter can do only 1023 steps (that are, including 0, 1024 states) Step 1024 will be the 11th bit you not have! Try it with a 2 or 3 bit converter example, please! |
| 02 maa 2020 11:13:08 | Arduino wattmeter | Raju | Hi Freddy, How to upgrade with Bluepill board, to get 12bit adc resolution (STM32F103C8T6) |
| 02 maa 2020 09:22:23 | Arduino wattmeter | Matt | Hi Freddy, I hope you are still monitoring this comment thread. :) I would like to monitor power usage and charging on a remote 12V system with a solar panel and some intermittent loads, with data logging. I have two questions: 1. Would this circuit be suitable for accurately measuring consumption and/or charge (net energy use) in a DC system by connecting it at the battery so it sees all charging and drain as positive and negative current, then modifying the software? 2. I would like to reduce the power usage of the meter as much as possible. I am thinking to remove the LCD display; log data to an SD card or similar and retrieve it via serial connection to another system twice daily; simplify the rate and variety of measurements to only average voltage, current and total Ah per 30sec interval or so. Would this circuit be a good basis for experiments in that direction, and how low do you think the power usage could realistically reach? Many thanks, Matt |
| 04 feb 2020 11:27:37 | Fast Lux meter | Freddy | You can make the luxmeter less sensitive by lowering the value of R1. As An example: halving the resistance value dubbles the maximum range. And if you only interested in the flash-waveform shape, you can measure it indirectly by pointing the luxmeter to a wall or another (darker) surface. |
| 04 feb 2020 02:16:17 | Fast Lux meter | Raymond | Maximum reading is 6000lux? Camera flash seem over this value. It is not suitable for metering camera flash lux?\\ Thanks you. |
| 03 feb 2020 16:52:37 | Fast Lux meter | Freddy | The power supply voltage must be at least 12 V and may never exeed the OP37 absolute maximum rating of 22 V. The output voltage lays between 0 volt @ 0 lux, and ~3 volt @ 6000 lux. |