Digital Speedometer 12v
- Thread starter Deoodles
- Start date
Adam-NLV
Well-Known Member
Yes , a little board to 'hard wire' & solder it. That's one way and prob the easiest.
Another way is to wire-rap it. uses a wire-rap tool.
https://en.wikipedia.org/wiki/Wire_wrap
If you want to wire rap it, you would get these sockets for the 555 chip like I did.
https://www.ebay.com/itm/10-x-8-Pin-Machine-Tooled-IC-Socket-USA-SELLER-FREE-SHIPPING/233103897104?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649
The chip socket is wire-rapped and then the 555chip is plugged into the socket.
Another way is to wire-rap it. uses a wire-rap tool.
https://en.wikipedia.org/wiki/Wire_wrap
If you want to wire rap it, you would get these sockets for the 555 chip like I did.
https://www.ebay.com/itm/10-x-8-Pin-Machine-Tooled-IC-Socket-USA-SELLER-FREE-SHIPPING/233103897104?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649
The chip socket is wire-rapped and then the 555chip is plugged into the socket.
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Adam-NLV
Well-Known Member
Yep, its definitely Old school but that's the way I was taught in college. I wonder if they even teach that method, they probably use a 3D printer to make their boards now!
My final project was an international digital clock, all wire wrapped! What a mess to troubleshoot...
It worked , sometimes.
My final project was an international digital clock, all wire wrapped! What a mess to troubleshoot...
It worked , sometimes.
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Adam-NLV
Well-Known Member
Thats what I was telling Ray. When i was into this stuff in the 1980's a power Transistor would cost $24.00 each and if you blew it, you were SOL.
Now everything is so really very cheap, it blows my mind.
Nothing wrong with progress, or old-school know-how. What works, works.
You guys do realize that, if you succeed with this, you'll have made your own "speedometer healer"...and be able to dial-in the accuracy with precision. (I am guessing that you're talking about trimpot adjustment) The toughest aspect will be coming up with a calibration standard to base your adjustments. There are a few ways of doing that, which don't require specialized equipment.
You guys do realize that, if you succeed with this, you'll have made your own "speedometer healer"...and be able to dial-in the accuracy with precision. (I am guessing that you're talking about trimpot adjustment) The toughest aspect will be coming up with a calibration standard to base your adjustments. There are a few ways of doing that, which don't require specialized equipment.
Lol yes that’s what it would be. But the education counts for something. This is slightly more fun than trying to figure out what happened to 2nd gear
It’s got to be range adjustable to account for variations in speedometer gears and tire sizes. I just don’t know how. Thankfully Adam is the mentor here. 
In effect, what you're trying to accomplish is a change in the number of impulses the speedometer "sees" per wheel rotation...only it's a fraction per wheel rotation. Best analogy I can provide would be an automotive timing light with a "dial-back" function, used to determine, in realtime, how many degrees of ignition advance you're getting when there are no visible degree markings on the harmonic balancer.
Adam-NLV
Well-Known Member
Not so much to change the number of impulses per rotation but the length of the impulse aka:frequency that's happening per second not per rotation.....My initial idea is just to slow the impulses (frequency) down or to delay them from 20 ms that they are at now when drill is at full speed, and adjust the 'pot' (potentiometer) to 15 ms delay time. or In layman's terms; slow down the pulse to beat at fifteen million times a second down from the 20million times a second it beats now.
We'll use the 555 to do this.Thanks for the enthusiasm, I'm getting stoked for this too! Will check the mail this morning and hopefully the 555 from California are here.
The ones I ordered from China 40 chips for $2.99 LOL
will take some time to get here..
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That's a much more accurate description. It is all about the pulse width.Not so much to change the number of impulses per rotation but the length of the impulse aka:frequency that's happening per second not per rotation.....My initial idea is just to slow the impulses (frequency) down or to delay them from 20 ms that they are at now when drill is at full speed, and adjust the 'pot' (potentiometer) to 15 ms delay time. or In layman's terms; slow down the pulse to beat at fifteen million times a second down from the 20million times a second it beats now.
Thanks for the enthusiasm, I'm getting stoked for this too! Will check the mail this morning and hopefully the 555 from California are here.
The ones I ordered from China 40 chips for $2.99 LOL
Adam-NLV
Well-Known Member
That's great Ray! You are on your way to circuit building know how.
That output that lights up the LED will be fed into your digital speedometer. But instead of that Red button switching the 555, we will use the sensor output as the button to switch the 555.
(then delayed by 5 milliseconds afterwards !) that will give us a calibrated reading (hopefully).
That output that lights up the LED will be fed into your digital speedometer. But instead of that Red button switching the 555, we will use the sensor output as the button to switch the 555.
(then delayed by 5 milliseconds afterwards !)
that will give us a calibrated reading (hopefully).
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Both of you guys are doing work that's above my pay grade(!). This is cool stuffs.
FYI, if I didn't f*ck up the math too badly, the stock tire size + a single pulse (once-per-rotation) should work with ~56ms between pulses (1120rpm@60mph). Thus, Adam's 5ms delay is roughly 10%...a pretty damned good ed-u-macated guess, if I do say so.
FYI, if I didn't f*ck up the math too badly, the stock tire size + a single pulse (once-per-rotation) should work with ~56ms between pulses (1120rpm@60mph). Thus, Adam's 5ms delay is roughly 10%...a pretty damned good ed-u-macated guess, if I do say so.
Adam-NLV
Well-Known Member
Good news, i found one of my part stashes! Found the box that the box was in but a box was stacked on top of it...
This why i'm not current up on component prices; i have my own component supply and don't usually need to buy any.. I have another box with more part boards somewhere in some box.. I see mostly Op amps which are for audio builds but I will keep looking for a 555.
This why i'm not current up on component prices; i have my own component supply and don't usually need to buy any.. I have another box with more part boards somewhere in some box.. I see mostly Op amps which are for audio builds but I will keep looking for a 555.
