Telrad Flasher

[Tomatobro]

I own several Telrad finders and all are equipped with a 555 timer flasher. Having just ordered another one I thought it was time to bring the flasher circuit into the 21st century

A 12f629 pic will run at 2 volts so I programmed one to give me a "soft" rise and fall in luminosity intensity. The pic drives the LED through a PNP transistor. The timing of the rise and fall is fixed along with the off time.

I have added a 4.7k resistor across the Telrad pot to open up the brightness adjustment span on the lever.

 

 

[johninderby]

Ah the trusty old 555. Been around forever. Somewhere I’ve got a box of them. Had some LM3909 as well put away somewhere but can’t find them.  

 

[sloz1664]

I own several Telrad finders and all are equipped with a 555 timer flasher. Having just ordered another one I thought it was time to bring the flasher circuit into the 21st centuryA 12f629 pic will run at 2 volts so I programmed one to give me a "soft" rise and fall in luminosity intensity. The pic drives the LED through a PNP transistor. The timing of the rise and fall is fixed along with the off time. I have added a 4.7k resistor across the Telrad pot to open up the brightness adjustment span on the lever.

I love this idea as I find contorting my body to look through a telrad and view the star I am aligning to can be difficult at the best of times. This idea would help immensely. the Any chance of a circuit diagram and programme information please.

Steve

 

[Tomatobro]

18 hours ago, sloz1664 said:

I own several Telrad finders and all are equipped with a 555 timer flasher. Having just ordered another one I thought it was time to bring the flasher circuit into the 21st centuryA 12f629 pic will run at 2 volts so I programmed one to give me a "soft" rise and fall in luminosity intensity. The pic drives the LED through a PNP transistor. The timing of the rise and fall is fixed along with the off time. I have added a 4.7k resistor across the Telrad pot to open up the brightness adjustment span on the lever.

I love this idea as I find contorting my body to look through a telrad and view the star I am aligning to can be difficult at the best of times. This idea would help immensely. the Any chance of a circuit diagram and programme information please.

Steve

 

What skills/equipment do you have? Can you program pics? I could post  you a pre programmed Pic but are you ok to do the rest? Send me a message and I will see what I can do to help.

[Tomatobro]

I have sketched out what the modifications are. The Pic and transistor are mounted on a small piece of stripboard.

[sloz1664]

Thank you so much Tomatobro.

Steve

[Tomatobro]

Not sure SGL will accept the code listing but here goes.

Telradcode.odt