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Re: Bespoke digital dash for T25
Posted: 18 May 2013, 20:48
by ed_crouch
Too right. I thought I was being well clever. Gonna pack up my toys and trudge home now. Bastards.
Only kiddin! There's some seriously good work here. Hats off to you!
Re: Bespoke digital dash for T25
Posted: 18 May 2013, 21:07
by scottbott
what happened to that rather nice looking dash that was layed out ready to be assembled?
Re: Bespoke digital dash for T25
Posted: 18 May 2013, 21:58
by syncroandy
Yes, I'd like to hear more about the Arduino board Ed. How many inputs and displays can one board support? I'd like to to hook up oil temp and pressure using standard vdo senders, and a type k thermocouple for egt.
Re: Bespoke digital dash for T25
Posted: 19 May 2013, 08:09
by KINGPRAWN
scottbott wrote:cannot understand what you are talking about,might as well be greek,but a digital dash would be good,will keep my eyes on to this post

Ditto that!
Re: Bespoke digital dash for T25
Posted: 19 May 2013, 20:11
by nutbox
Definitely watching this thread I have the same board but have a 3.2" tft and shield with memory card slot,but I do really no how to code much.
So I am glad someone is doing this and can show they way it's done if you don't mind
You can get a T piece that you can put in the oil pressure hole and the screw the oil pressure and oil temp sensors to.
I also had a thought whether you could control the cooling flaps with a stepper motor to replace the thermostat because I ain't got one on mine.
Cheers dazz
Re: Bespoke digital dash for T25
Posted: 19 May 2013, 21:17
by discipleofsketch
ed_crouch wrote:
Any interest or am i out here on my own?!?
I spent a few evening researching how I could add a digital rev-counter to my diesel T25 (1Y, no ECU), as it doesn't have a rev counter at all. Ended up reading a blog post about a a DIY project where a guy had a dab of paint on the flywheel, with some kind of sensor getting a reading from that. Would love to hear of other ways I could get some digital engine data to play with from my entirely mechanical engine! I was thinking of having an on-board raspberry Pi + small LCD monitor for the readout
Re: Bespoke digital dash for T25
Posted: 19 May 2013, 21:23
by ed_crouch
On something like a diesel you could put a trigger wheel on the crank pulley and use a variable reluctance or a Hall effect sensor. This will produce a pulse train proportional to engine speed, and a microprocessor can run a frequency counter code to operate a gauge or readout. Almost all efi systems use trigger wheels.
Re: Bespoke digital dash for T25
Posted: 20 May 2013, 16:41
by icosahedron
Keep it simple on a diesel and do it the way VW went about it. The alternator frequency is directly proportional to engine speed.
Re: Bespoke digital dash for T25
Posted: 21 May 2013, 11:35
by discipleofsketch
icosahedron wrote:Keep it simple on a diesel and do it the way VW went about it. The alternator frequency is directly proportional to engine speed.
yep, I just need some sort of analog-digital interface to put it into the domain I understand (as a software developer, not electronics expert!).
Re: Bespoke digital dash for T25
Posted: 21 May 2013, 21:46
by ed_crouch
You'll be needing a uprocessor IDE then! I use Arduino.
Re: Bespoke digital dash for T25
Posted: 22 May 2013, 10:44
by syncroandy
Found a useful introduction to connecting analogue automotive senders into the 'digital domain' here:
http://forum.arduino.cc/index.php?topic=87073.0
Basic circuit diagram for an analogue sender input:
