[sheckta]

Hi, i'm here to ask a question to everybody in this wonderfull community...
Firstly please excuse me if i have a soso english... i'm french and i learned half at school and half with video games XD

Well... let's get into it, i have been searching for a Power Distrib Module and i wonder if anyone here has any plans to make one based on arduino or not...?

Making one myself is out of the question because i have no knowledge of electronics at all neither do i in programming...

But i know some here can do it!

I'm waiting for your input on that subject!

[theonewithin]

Power distribution module????


A fuse/relay box?

[PSIG]

PDMs have been discussed quite a lot (especially on Slack), and was one potential goal of the GPIO project. It has also been mentioned here in threads such as the Mini GPIO, but no specific PDM efforts have been reported that I've seen. Check the GPIO threads here and the info in the Wiki for possibly helpful info. Perhaps @dazq or @NickZ can add some more specific background here.

David

[dazq]

As psig said I have been working on a pdu/pdm , it is an evolution of gpio .
I have a couple prototypes under test .
Due to the serious nature of the modules I want more testing done before I release the code, yes the firmware and hardware will be opensource , but a built unit or perhaps a kit will be available when the time comes.

[EdMcGuirk]

Just curious because recently I have seen a couple of commercial power distribution modules promoted on some youtube car channels. The first device I saw was the ECUmaster PMU which acts as a relay and fuse panel however these devices seem to be in the $1000 plus range.

I was wondering if current could be reasonably accurately measured (10% is probably good enough) through the mosfet Rds? (I saw a white paper somewhere on this topic-I can't remember where) For example an IRF4905 mosfet has an Rds of .02 ohms and a current limit of 74 amps. It should show a voltage drop of .4 volts at a typical fuse value of 20 amps or .1 volts at 5 amps.

Throw in an ADS1115 differential ADC and a CD74HC4067 16-Channel Analog Multiplexer and I think the functionality of these PDMs can be cheaply duplicated.

Am I naive to think this would work?

(picture is a bit fuzzy, PDF is clear)

PDMcurrentsense.png (11.81 KiB) Viewed 7450 times

PDMcurrentsense.pdf

(20.43 KiB) Downloaded 233 times

[dazq]

I use a few different types of driver.
When using just a simpler MOSFET I use acs712 type or similar to monitor the current.
I did try a low ohm shunt with constructed monitoring but wasn't happy for use as an electronic fuse replacement.
Otherwise I use high and low side drivers which usually have monitoring and current limiting built in.
Even using these the cost of the unit is very low, it's the development you pay for.

[JHolland]

Just curious because recently I have seen a couple of commercial power distribution modules promoted on some youtube car channels. The first device I saw was the ECUmaster PMU which acts as a relay and fuse panel however these devices seem to be in the $1000 plus range.

I was wondering if current could be reasonably accurately measured (10% is probably good enough) through the mosfet Rds? (I saw a white paper somewhere on this topic-I can't remember where) For example an IRF4905 mosfet has an Rds of .02 ohms and a current limit of 74 amps. It should show a voltage drop of .4 volts at a typical fuse value of 20 amps or .1 volts at 5 amps.

Throw in an ADS1115 differential ADC and a CD74HC4067 16-Channel Analog Multiplexer and I think the functionality of these PDMs can be cheaply duplicated.

Am I naive to think this would work?

(picture is a bit fuzzy, PDF is clear)

PDMcurrentsense.pngPDMcurrentsense.pdf

Its not a very practical method, the problem is that Vds changes considerably with temperature and gate voltage. There are drivers that use the Vds value for feedback short circuit protection but they have a very wide operating area. If you want current feedback then a current sense resistor is much more accurate.

[NickZ]

I have been looking into and started designing one a little while ago. Still a work in progress. In theory is seems easy, but finding the right components to handle what maybe long term high load needs good research.
But basically finding some good switching mosfet's and current load sensing IC fed back to a arduino.
I have partly made the switch panel that uses a 3 wire communication and multiple switches, its just the load circuits to do.

[EdMcGuirk]

Is it worth getting complicated with having one current sensing circuit and cycling it into each power path?

[PSIG]

I don't know that it would save anything, as your sensing would have to follow through high-amp switching? Depends on your scheme and sensing method. Hmm. I have been using the same method as @dazq with current-sensing ICs, so simplest is using one per-channel, as all current flows through them. Perhaps you could read each one in sequence rather than effectively simultaneous, but I'm not sure if that's saving anything in itself. What are you thinking, Ed?

David