Nice project! You could make a real true RMS meter with this by implementing the RMS integral in your uC if it is fast enough. I would like that better than other methods some "true RMS" DMMs use.
Michel On Jun 4, 6:39 pm, jb-electronics <[email protected]> wrote: > Tobias, > > the INA219 is amazing! Do you know if there are any breakout boards for > 2.54mm pcbs? > > Jens > > > > > > > > > Thank you all =) > > > For the past couple days we have been working on the user interface. > > This is the result do far: > >http://www.youtube.com/watch?v=NwBKmTFYuQk > > > The rotary encoder changes between the different measurements. As I > > add more features I can just add more cases to the loop, making it > > easy at the software. > > > Bill: Vitaly wrote me a email offering some for sale. Lets see how > > this turns out. Otherwise I will go to ebay. Your link came back "Item > > 190675257 is no longer available." Do you remember the name of the > > seller? > > > Jens: I am still studying how to approach other measurements, but I am > > happy with the results so far. I think I failed on explaining how I am > > doing it. Take a look at the INA219. It is the one I am using. For > > less than $3,00 I gave it a shot and it works quite nice. "The INA219 > > senses the small drop across the shunt for shunt voltage, and senses > > the voltage with respect to ground from VIN for the bus voltage". It > > looks like the hobbyists are just starting to use it, or my google > > skills are quite modest, because I could not find anything better than > > the datasheet. Anyway I ended up drawing the component at eaglecad and > > writing the library for the arduino. > > > I am trying some R and C measuring designs on the breadboard but > > nothing too promising so far. > > > A box is on the way. At least is on the paper. > >http://tobiasmugge.files.wordpress.com/2012/06/nixieatmegav3.png > >http://tobiasmugge.files.wordpress.com/2012/06/nixieatmegav3_frontal.png > >http://tobiasmugge.files.wordpress.com/2012/06/nixieatmegav3_lateral.png > > > Tobias > > > On 1 jun, 04:42, jb-electronics<[email protected]> wrote: > >> Hello Tobias, > > >> nice project! I would very much like to see how this evolves. > > >> But just one thing: You mention you measure voltage before and after the > >> shunt to get a current reading. This sounds to me like you are wasting a > >> lot (!) of ADC resolution for that fact because you would always > >> subtract two voltages who are roughly of the same magnitude. > > >> Ever thought about an instrument amplifier (very sensitive differential > >> amplifier) across the shunt? You could also use some current sense ICs > >> who have all of these included (Linear Technologies has a lot of them). > > >> Jens > > >>> Hello, I am new to this group and I would like to introduce myself > >>> with a project that I have been working on. > >>> This is my attempt to create a DMM using IN-12s, a IN-15A and a IN-15B > >>> as display. I used my nixie clock board as base, so it can double as a > >>> clock when not used as multimeter =) > >>>http://tobiasmugge.files.wordpress.com/2012/05/dscn4039.jpg > >>>http://tobiasmugge.files.wordpress.com/2012/05/dscn4034.jpg > >>> The uC is a Atmel Atmega328p. I downloaded arduino bootloader on it. > >>> I am using supertex HV5522 as drivers for the nixies. Two of them for > >>> 64bits. A friend of mine wrote a library for it that includes > >>> brightness control via the HV5522 blank pin. He is currently > >>> programming the clock while I work on the DMM. > >>> Power consumption is around 3W. DC power supply from 9 to 12V. The > >>> voltage for the tubes is boosted from the input voltage using a switch- > >>> mode power supply based on the TubeHobby one. > >>> The pictures and video shows voltage reading: is the only measurement > >>> I implemented on the software so far. Still thinking how to approach > >>> the scales/units. > >>> I have a shunt resistor on the board and I plan on having voltage, > >>> current, power, frequency and duty cycle for DC. I am using a I2C A/D > >>> with a PGA, measuring voltage on both sides of the shunt. This was a > >>> fairly cheap solution, but the way I did it only works for DC and the > >>> range is 0 to 32V. But allows me to measure current and voltage at the > >>> same time =) > >>> I have a video of the thing > >>> working:http://www.youtube.com/watch?v=PNYnFTeADow > >>> The maximum error I measured was 1,2% when comparing to my not-that- > >>> bad-multimeter. > >>> I plan on implementing resistance, capacitance, inductance and AC > >>> voltage/current capabilities. Suggestions will be greatly appreciated! > >>> The IN-15A showed on the pictures is not fully lightened. I am > >>> following Nick suggestion to burn it at 6mA for one hour. So far so > >>> good. > >>> I am still trying to find some IN-12B as those include the dot. I do > >>> have 4 bits free on the HV5522 that I could use to drive IN-12B dots > >>> or INS-1. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
