Speedlimiter circuit using lm2917

Thread Starter

Manthi

Joined Nov 13, 2010
14
Couple of questions.

Is the both lines what come on battery same line or? (+)
All triangels are gnd?
What is that rly_sign1no and it lookin like a coil? is that what you get the imbulse for testing?
And the 2n3906 transitor is connected onthe gruond?? and which (emiter or collector) coming to gnd??
Same as whit q3
Triger? meaning somthing?
Why reed switch is connect to the gnd?
I noticet that r4 is huge 1MΩ

R2 200k Pot?

The second lm555 7dis and 2 triger is empty?

All c:s are capizators?

After r4 there is c5 and and after that is another c5?

My school shuold have theese all.


Thanks a lot :)
 

SgtWookie

Joined Jul 17, 2007
22,230
Couple of questions.

Is the both lines what come on battery same line or? (+)
There is just one battery supply shown, BAT, on the left.
The power to the 555 timers is regulated by the Zener diode D1, and it's current is limited by R5. If your nominal system voltage is 14 with the engine running above idle, the Zener should get 20mA current, which will keep the voltage pretty stable. It's an inexpensive shunt regulator.

The voltage to the relay coil does not need to be regulated.
All triangles are gnd?
Yes.

What is that rly_sign1no and it lookin like a coil? is that what you get the impulse for testing?
The one on the left labeled SW1 is an approximation of your reed switch being closed by a magnet every 96mS.

The one on the right is an actual relay.

And the 2n3906 transitor is connected on the gruond?? and which (emiter or collector) coming to gnd?
Q1's collector is connected to ground.
Same questions with Q3
Q3's emitter is connected to ground.

Keep in mind that the transistors are shown as standard symbols; nothing special about them. With PNP transistors, the arrow on the emitter points towards the base; with NPN transistors the arrow on the emitter points away from the base.

Trigger? meaning something?
The "Trigger" text is a label for that node. I labeled that node so it would have a meaningful name when plotting the signal, as shown in the simulation results.

Why reed switch is connect to the gnd?
When the reed switch closes, it places a momentary ground, which trips the trigger and causes Q1 to discharge C1.

I noticed that r4 is huge 1MΩ
Yes; that's to give U2 a greater time-out time than U1.

R2 200k Pot?
Yes.

The second LM555, 7-dis and 2-trigger is empty?
Yes. There is no connection to those terminals.

All C's are capacitors?
Yes.

After r4 there is c5 and and after that is another c5?
Don't get confused with the symbol C5 which is a capacitor, and the node label C5. That was simply a way to show what the voltage on C5 is on the plot.

My school shuold have theese all.
Keep in mind that you should use ceramic or metal poly film capacitors that are stable over a wide temperature range.

You should test each capacitor before wiring it up, as their values can vary quite a bit. If they measure considerably different from what I have shown in the schematic, you will need to adjust the values of the resistors to match.

Keep in mind that your circuit will need to be built very ruggedly, as operating on a scooter will be a very harsh environment. Vibration, shock, temperature variations, and humidity/fluids will be a problem. You will likely need to coat the circuit with an acrylic lacquer to seal it from the elements, and then mount it in an enclosure of some kind.
 

shortbus

Joined Sep 30, 2009
10,045
If the speedometer is electronic(from a previous post), why couldn't the pulses be taken from that ? Then a frequency to voltage converter like a LM331 can be used. Measure the voltage output at the speed you want to limit at and use a comparator to shut down ignition or fuel injection.
 

Thread Starter

Manthi

Joined Nov 13, 2010
14
There is just one battery supply shown, BAT, on the left.
There is leaving 2 lines?
The one on the left labeled SW1 is an approximation of your reed switch being closed by a magnet every 96mS.
So i dont need it.

Keep in mind that your circuit will need to be built very ruggedly, as operating on a scooter will be a very harsh environment. Vibration, shock, temperature variations, and humidity/fluids will be a problem. You will likely need to coat the circuit with an acrylic lacquer to seal it from the elements, and then mount it in an enclosure of some kind.
I have ready solition on this.
If i pack it tide will the tempature inte circuit rise up?


I see u1 gnd is going gnd and 12v power line and its lookin like short circuit?
 
Last edited:

SgtWookie

Joined Jul 17, 2007
22,230
There is leaving 2 lines?
The battery negative terminal is also connected to ground.

re: SW1:
So i dont need it.
You need the reed switch you said you were going to use.

re: rugged, shock, vibration, temperature:
I have ready solution on this.
OK, good.

If i pack it tight, will the temperature in the circuit rise up?
There should be very little power used in this circuit.


I see U1 gnd is going to gnd and 12v power line and its looking like short circuit?
No, it's connected to the negative battery terminal, which is also chassis ground.

Perhaps I should have omitted the "ground rail" and just used ground symbols everywhere. I simply used ground symbols where it was not convenient to run a wire.
 

Thread Starter

Manthi

Joined Nov 13, 2010
14
Ok now i get it :)
But is the c5 connected to the rail whic goes to u2 6thrs terminal
I think it´s not. Fix me then if i am wrong :D

u1 u2 have the 8 and 4 terminals connected same line?
 

SgtWookie

Joined Jul 17, 2007
22,230
Maybe this project is too hard for you right now.

I think you should leave your scooter as it is for awhile, and start experimenting with some circuits that are much more simple. Otherwise, you may be left stranded with no scooter to ride, and you live too far away (nearly 8,000km) for me to come and help you fix it.
 

Thread Starter

Manthi

Joined Nov 13, 2010
14
I showed the circuit to my teacher.
My teacher and he solved the full circuit. This will be free experiense to me and my scooters is throttled and when i get this working i take throttleds off.
 
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