Tacho for 1 cylinder 2 stroke

heavywater · 13th March 2012, 9:44 PM

Hey,

Just wondering if anyone has an idea of how I could build a tachometer for my bike engine using maybe seven segment displays (preferably 0 - 9,999RPM) ?

Thanks.

paulvk · 13th March 2012, 10:02 PM

You use the pulse from the spark plug. This is the easy way as you only need a small pulse transformer cliped around the lead to detect it. I think silicon chip had one as a project search their site for it.

Regards Paul

mike-s · 13th March 2012, 10:12 PM

Remember if you do this it will be a compromise between fast refresh speeds and ease of readability of the numbers onscreen. Silicon chip mag had an article about making this very thing a few years ago. They may have plans/pcb's for this. Another alternative is maybe altronics if they are still around, they had a lot of kits in their cat'n'dog,uhm, catalog.

heavywater · 14th March 2012, 1:24 PM

Thanks lads i'll check those out

dualmassager · 14th March 2012, 2:53 PM

Most tachos off the self are for 4-stroke, so be careful. Most of these tachos just hook up into the ignition source and measure the frequency.

aXis · 14th March 2012, 3:57 PM

It might sound overkill, but if you're going to build your own I'd reccomend using an arduino and a character LCD display. The wiring is quite simple, and you'll have more flexability in the display. You could also display more than just RPM, eg battery voltage & temperatures.

The Character LCD's on ebay are dirt cheap and very readable. I'd go for one with few lines but larger font - search for "Character LCD large" - I can see there is a 16x1 with 8mm characters here for only $7.

Programming would also be dead easy - have a regular 1 second timer, count the number of pulses between the start and end of the timer, then update the display.

mike-s · 14th March 2012, 5:38 PM

Quote:

Originally Posted by dualmassager

Most tachos off the self are for 4-stroke, so be careful. Most of these tachos just hook up into the ignition source and measure the frequency.

Configure it for use with a twin 4 stroke, problem solved.

ywn · 14th March 2012, 6:01 PM

i use one of theres on my rotax http://www.alfano.com/home.php

it will tell u speed if u set up the gering and wheel size as it works on revs to determen the speed ( so when idling it will have a seepd reding but once moving its will be fine . it has water temp sensers

13th March 2012, 9:44 PM	#1
heavywater Member Join Date: Oct 2009 Location: South Australia Posts: 178	Tacho for 1 cylinder 2 stroke Hey, Just wondering if anyone has an idea of how I could build a tachometer for my bike engine using maybe seven segment displays (preferably 0 - 9,999RPM) ? Thanks. __________________ HAF932\|i7 920 @ 4.20Ghz\|NH-U12P-SE\|6GB Trident 1600Mhz\|EX58-EXTREME F12\|Gainward GTX 275\|150GB Raptor\|4x 250GB Hitatchi's\|Thermaltake Toughpower 850\|Death Adder\|Dell Keyboard\|Benq FP222W\|

13th March 2012, 10:12 PM	#3
mike-s Member Join Date: Dec 2003 Location: Sydney, Australia Posts: 1,726	Remember if you do this it will be a compromise between fast refresh speeds and ease of readability of the numbers onscreen. Silicon chip mag had an article about making this very thing a few years ago. They may have plans/pcb's for this. Another alternative is maybe altronics if they are still around, they had a lot of kits in their cat'n'dog,uhm, catalog. __________________ Successfull trades: RakOon, drfbro, mR_CaESaR, Spyfox If I've got crap for sale on ebay you like, click here. Old hardware giveaway thread here. Sony Vaio Club Member #21

14th March 2012, 1:24 PM	#4
heavywater Member Join Date: Oct 2009 Location: South Australia Posts: 178	Thanks lads i'll check those out __________________ HAF932\|i7 920 @ 4.20Ghz\|NH-U12P-SE\|6GB Trident 1600Mhz\|EX58-EXTREME F12\|Gainward GTX 275\|150GB Raptor\|4x 250GB Hitatchi's\|Thermaltake Toughpower 850\|Death Adder\|Dell Keyboard\|Benq FP222W\|

14th March 2012, 2:53 PM	#5
dualmassager Member Join Date: Aug 2009 Location: Melbourne Posts: 949	Most tachos off the self are for 4-stroke, so be careful. Most of these tachos just hook up into the ignition source and measure the frequency. __________________ Main Rig:Intel i7-930\| ASUS Rampage III Extreme \| G.Skill Sniper + Trident 18GB\| Powercolor 5870 1GB PCS+ + ASUS 5870 v1 1GB (XFire)\| Enermax Modu87+ 700W \| NZXT Tempest \| Samsung F3 1TB \| Dell U2311H + 2x AOC i2353PH (IPS 5760x1080 )\| ATH-AD700/Logitech R10 /Denon C751

14th March 2012, 3:57 PM	#6
aXis Member Join Date: Jun 2001 Location: Kalgoorlie, WA Posts: 3,337	It might sound overkill, but if you're going to build your own I'd reccomend using an arduino and a character LCD display. The wiring is quite simple, and you'll have more flexability in the display. You could also display more than just RPM, eg battery voltage & temperatures. The Character LCD's on ebay are dirt cheap and very readable. I'd go for one with few lines but larger font - search for "Character LCD large" - I can see there is a 16x1 with 8mm characters here for only $7. Programming would also be dead easy - have a regular 1 second timer, count the number of pulses between the start and end of the timer, then update the display. __________________ Former OCAU Extreme Cooling Club H2O Member Intel Core Duo E6600 Noctua NH-U12F

13th March 2012, 10:02 PM	#2
paulvk Member Join Date: Mar 2010 Posts: 698	You use the pulse from the spark plug. This is the easy way as you only need a small pulse transformer cliped around the lead to detect it. I think silicon chip had one as a project search their site for it. Regards Paul

14th March 2012, 6:01 PM	#8
ywn Member Join Date: May 2003 Location: port macquarie {nsw} Posts: 817	i use one of theres on my rotax http://www.alfano.com/home.php it will tell u speed if u set up the gering and wheel size as it works on revs to determen the speed ( so when idling it will have a seepd reding but once moving its will be fine . it has water temp sensers __________________ -ABIT- Ownage #52 ATi Owners Club Member [#??] AMD Phenom Owners club # [ Intel Owners Club Member #38 ls1 v8