Simple Circuits

[ParkingLotLust]

Ive got a couple projects going on with my Celica, and these circuits would really help. Im trying to stay away from uC's if possible, but if what Id like to do gets too complicated (it shouldnt, but you never know) I might have to go that route.

#1
Push-to-start.
Basically, you'd push and let go of the button, it flips a relay for either a specific amount of time (3s probably), or stay holding the relay until it gets a signal from somewhere else (likely 5v or 12v), when it turns the relay off.

#2.
Gauge Sweep.
This one might prove to be a bit more tricky. I have yet to figure out all the details (sweep from 0v - ?) but Im looking at making a one-shot DC sine wave (picture an AC sine wave, put through a half-wave rectifier). On startup (upon a wire going high - basically when it turns on), it makes a sine wave that sweeps from 0v to an undecided voltage (figuring out the max. voltages needed), then back to 0v, all in about 3s. If possible, Id like it to hold at the peak voltage for about 0.5s

While it would be nice for someone to quickly throw these circuits together for me, I understand that you all have busy lives and dont have time to do this for me. However, it would be really helpful if you could point me to sites with similar projects, or explain how the circuit would work, and I could build it in a sim and go from there.

 

[Super_voip]

Look for Triangular or ramp generators

 

[ParkingLotLust]

#1 will look like this:
**broken link removed**
Out would be connected to a relay, the switch would be the start switch. The pulse is around ~1.5 - 2 seconds (wont know exactly until I build it).

Still unsure about #2. A triangle or ramp generator is the basic idea I want, but I only want positive voltage, and the triangle/ramp generators Ive looked at in the sim all cycle from + to -

 

[HarveyH42]

Wouldn't a diode block the unwanted part of the cycle?

 

[ParkingLotLust]

I just figured one out using two op-amps, but Ive just learned (after some thorough reading) that the gauges use PWM (manual says "pulses") to control their placement, not voltage. Any way to vary the cycle from 0 - 100% and back to 0% without using a uC? Ive never looked much into PWM (assuming thats what Ill need).