Source code for Yaris Tachometer

[CtrlAltDefeat]

Originally Posted by metalshark

The biggest problem is the BS2 chip costs $50. I need to re-prototype this project using the new Parallax Propeller chip since they just dropped the cost to $7.95.

yes, $50 for just the chip would be way too much, an aftermarket tach would cost less. The Propeller version, however, sounds right up my alley... I think it would look good with rectangle or square LEDs (or rectangle shaped covers) closely set together. It would be awesome to somehow incorporate it into the gauge cluster...

[metalshark]

Originally Posted by CtrlAltDefeat

yes, $50 for just the chip would be way too much, an aftermarket tach would cost less. The Propeller version, however, sounds right up my alley... I think it would look good with rectangle or square LEDs (or rectangle shaped covers) closely set together. It would be awesome to somehow incorporate it into the gauge cluster...

I've figured out how to do that but people with more experience than I already know the cost of this can be shrunk a lot by just going to a cheaper microprocessor. When I get two of these beta test units out into the field I'd rather just public domain all the technical data to a thread/sticky on Yaris-World.com and let the hobby members grow the project. A processor in the BS2 class can be had for about $5 and support up to 4 digital readouts with ease. One like the BS2p40 can support up to 8 digital readouts or even more with serial display panel. At that point its getting into the full dash board display area. This is the type thing the folks at scan-gage are good at. The Parallax Propeller can support a small video display complete with graphics.

[metalshark]

Originally Posted by CtrlAltDefeat

yes, $50 for just the chip would be way too much, an aftermarket tach would cost less. The Propeller version, however, sounds right up my alley... I think it would look good with rectangle or square LEDs (or rectangle shaped covers) closely set together. It would be awesome to somehow incorporate it into the gauge cluster...

Another Yaris-World member is incorporating the display into the steering wheel on a beta test unit. I'm porting the application over to a better, cheaper uP as suggested by a member that has more experience than I. With the reduced hours at work, I'm starting to make better progress on the hobby.

[CtrlAltDefeat]

I am very interested in this... If I read the schematics correctly it uses LEDs to show the revs... how responsive will this be? If it's cheaper then an aftermarket tach and can be made to look good I would love a DIY tach... trying to think of where would be best to put the LEDs...

[metalshark]

http://i351.photobucket.com/albums/q...il209DL066.jpg
http://i351.photobucket.com/albums/q...oStichWire.jpg
http://i351.photobucket.com/albums/q...1/HPIM1368.jpg

The first picture is the trial layout.

The second picture is the stitch wire prototype I've used in the car for a year now.

The third picture is how I installed 15 LEDs in the dash. The display is currently set to start flashing all lit lites at 4 Hz when my revs hit my 6000 RPM shift point. The top red comes on at 6'800 RPM as programed and, yes the mill will make it.

[metalshark]

Originally Posted by CtrlAltDefeat

I am very interested in this... If I read the schematics correctly it uses LEDs to show the revs... how responsive will this be? If it's cheaper then an aftermarket tach and can be made to look good I would love a DIY tach... trying to think of where would be best to put the LEDs...

The BS2 chip scans at 20,000 cycles per second on its clock. The entire code is less than 100 lines. The output display driver section is a rather primitive analog/linear op-amp arrangement but it is very fast. This design is WAY faster in its response than any mechanical tachometer needle can possibly be. The code uses the pulsein command for data and in a worst case situation will generate an accurate RPM number in one revolution of the crankshaft.

[POORSHA]

i would be interested in your extra board and parts. i have been looking for a tach like this for a while. pm me when you know more.

[Shroomster]

lol might want to pm PK about this...I've been trying for months w/o success to procure a gauge cluster for him....

[metalshark]

Originally Posted by Shroomster

lol might want to pm PK about this...I've been trying for months w/o success to procure a gauge cluster for him....

send him this link. http://www.parallax.com/Store/Access...%2cProductName

[metalshark]

Here are the photos at the end of the day. Testing so far: Power supply OK. Input circuit OK. 15 Led driver amps OK. Tomorrow I check out the RS-232 connection.