VW Beetle Choke Delay

while working on this I wanted to get an idea as to how long I should set the time delay I got my daughter to give the system a manual test getting her to disconnect the choke supply voltage and driving for a couple of minutes then pulling over and hooking up the choke supply than continuing to drive - what we found is that it didn't really make any noticeable difference. I've decided the project isntbgoingbto help in its current form. I'm thinking of reworking things and just making a data logger and making recording some temperature readings and work out a better solution - maybe some way of opening and closing the cooling flaps in the fan housing would be a better way to go

I picked up a couple of these super cheap Arduino UNO clones - What a PITA.

They use instead of an FTDI USB chip they use an infernal CHG340 chip yes there is a MAC driver for it

http://www.wch.cn/download/CH341SER_MAC_ZIP.html but the bastard driver produces a name like this

cu.wch ch341 USB=>RS232 fa210

The Arduino IDE doesnt like spaces and trys to write to the device at cu.wch which of course doenst exist. The only way I have managed to get the the things to work under OSX 10.10.5 is to create a symbolic link to the drive name.

sudo ln -s /dev/tty.wch\ ch341\ USB\=\>RS232\ 1450 /dev/tty.USB0

thanks to

http://arduino.stackexchange.com/questions/3700/rename-device-name-ch340-usb-to-serial-mac-os My recomendation is dont waste your money on this rubbish - stick to the real deal FTDI chips and saveyour self a world of pain. note the windows driver does appear to work

THe majority of this project revolves around the Dallas one wire temperature sensor the software for I borrowed heavily from http://www.pjrc.com/teensy/td_libs_OneWire.html

Each project I work on I work on trying to imporve what I do with code and try and understand it better. This time I wanted to look more at using functions - I was wanting to try making use of the abiity of a function to return a value ratherthan use global variables but I didnt quiet get there - maybe next time.

its a fairly sttaight forward code

Upon power up read the temp sensor. If its less than 10deg turn the power to the choke off.

then read the temp sensor every second untill the temp either rises to 20deg or 12000 milliseconds has passed (2 minutes) if either condition is true he power is aplied to the choke and it begins normal opperation.

as the circuit only is required to opperate for a couple of minutes - rather than hold a relay high the whole time I decided to use the normal closed contacts of the relay - this way the relay is only energised for the 2 minutes of opperation - once the time has exipred the circuit is no longer required untill the car is next started.