Thread: Arduino Modular Engine Sensors Unit (~$50)

Originally Posted by loanrangie

This looks right up my alley, pardon my ignorance what type of os for lack of a better word do/can these run ?

The arduinos have a boot loader that allows you to download custom code via usb. There is no os as such, you're writing code that directly interfaces the io and mcu resources.

Arduino has opened the world of micro electronics right over the last few years. When I last played with mcu's (both atmel and some Phillips/nxp only 4-5 years ago) you needed programmers which you could make yourself or buy off the shelf, and all io circuits generally needed to be built. I made use of some pre made boards with some idc headers which made life much easier but much more convoluted than todays stuff with simple plug in shields etc. What's even better about a lot of arduino boards is that they come with the isp header so you can still use your old programmers and code if you don't like the standard arduino interface.

My last project was a dual battery controller combined with a dual stage thermo fan controller configurable via a 2x16 lcd display. Was based on an atmega 128 ( http://www.futurlec.com.au/ATMega_Controller.jsp ) so had massive amounts of io to play with to expand in the future. It died when my mcu board blew up after sitting it on a metal screwdriver The board supplier was hopeless so got bored and packed it all up after that.

Sent from my Transformer Prime TF201 using Tapatalk 2

Thanks Stuee, i new it wouldnt use a normal os like windblows or linux , i guess language would've been a better word.
Sounds pretty cool what can be done, do i see a mini USB socket on Babicat's pic to use for programming ?

Yeh the one posted in this thread has a mini usb socket.

The model:
Arduino - ArduinoBoardNano

I gather the language is based off C++. Personally I prefer the more procedural languages like Basic and C as they better reflect the behaviour of the MCU (i.e process line by line), and they also compile into much smaller sets of code when loaded onto the MCU, which used to be important but modern chips have ample amounts of memory now days. Likewise those messing around with them before me would have preferred machine code.

I used to use the free version of this:
CodeVisionAVR

Haydent would probably be aware of this if he's come from rc multi-rotors, but when I finish the 101 I want to make my own drone using the ardupilot (An arduino based platform).

Back on topic, you need to put some thought into:
- what type of sensors you will use. i.e standard automotive VDO temp and pressure or basic RTD's etc. My preference would be towards using standard automotive sensors as they have been designed for the harsh environments, are easily available if broken and are easy to mount.

- the power requirements for all the IO. i.e 5V from the arduino board or reg, or 12V from the car system. This will change how much wiring is required to go in and out of the unit to sensors. Alternatively, if using the 5V, you may need an additional regulator depending on how much power is needed. You will also need to look at heat dissipation as the standard 5V regulators dropping down from 13.5V-14V while running will burn a lot of heat. Consider a switch mode 8V supply to drop down before the Arduino.

- how accurate you want the sensors to be. If using the cars battery to power sensors you may want to have a reference voltage feeding into the Arduino to make measurement adjustments (don't feed 12V directly into the arduino).

- how will you interface the arduino to all the sensors, outputs, screens etc. Its easy enough to prototype it up on a breadboard, but I would try and make use of as many components or "shields" off the shelf if you plan to sell any units in the future. The biggest pain in the ass when I did my projects was manufacturing a pcb, then a couple of months later wanting to add or remove components and redoing it all. Limiting yourself to wahts available commercially has a lot of restrictions, but also drastically cuts down your testing and troubleshooting time.

- how will you communicate between the display and sensor unit (arduino)? If you drive a display directly from the arduino you will use up a lot of valuable IO and resources. I have previously used a standalone serial display that used basic serial comms between the MCU and display to present information. Only used two pins and was reasonably easy to program. The display had its own controller as such that did all the hard work. If you use a display driven directly off the arduino consider using two arduino's and interface them with serial, I2C, or even bluetooth or wireless if you want to get fancy.

A similar project to what your doing but from 2009:
multidisplay - Arduino based open source display for interesting measurand´s of a car. - Google Project Hosting
Their V2 looks impressive but still in development.

Not much. Just a basic boot loader that loops the scripts you write and put on it to work with it's input/output pins.

Didn't realise there was a second page on my tapatalk...

Thanks for the breakdown stu.

Also just to clarify the USB port is really only for programming via it as a virtual com port. It doesn't act in host or slave mode...

As far as pins go, im going to start with an lcd in 4bit mode which uses 6 digital pins. The nano has 11 "free", so that leaves 5 for buttons to control it. Then there are 8 analog input pins.

So that means upto 8 sensors.

That's enough for now.

Im also keen on later making a second sender arduino box that lives under the hood to either reduce the number of wires going through the firewall to ~2 for a serial com link, or none of a wireless link where used. Also it could increase the potential number of sensors if needed.

Originally Posted by EchiDna

what kind of sensors can be attached to this thing? I've only seen thermistor types but to make it a goer, it really should have the ability to run upper/lower alarms at user defined set points for water temp, air temps from ambient to EGT, and items like oil pressure, boost gauge etc...

For sure I will be programming alarms, that's what it's all about for me.