Optoisolators have an LED on one side shining on a phototransitor (or something similar) on the other side. Turning on the LED turns on the transistor but there is no electrical connection between the two. That means, in our case, the pyro circuits can be separate from the microprocessor controlling them. Any ground bounce (due to high currents) or RF pickup on the long leads (aka antennas) is far less likely to affect the operation of the processor/sensor system. I don't know the circuit in detail so that's about all I can say with confidence . They are typically used where high voltages need to be safely controlled.I have no idea what an optoisolator does, but the two of them were next.
Thanks for the good pics. Need to get my next cataract surgery out of the way at the end of January before getting started on my Eggtimer builds. Do you have any favorites when it comes to soldering gear?
Your soldering looks very good. The eggtimer should work as expected.
The surface mounted parts on the other eggtimers are not that much harder to do. I think you do have the soldering skills.
Why the vertical resistors? Space savings? Is that your trick or does Eggtimer recommend doing so?
It's really a very efficient technique, since through-hole boards normally require a good bit of vertical space anyway. And it looks cool.Pre-SMT, vertical resistors were a thing... if you look at older R/C receivers, virtually all of them had vertical resistors to save space.
Got to watch out for the bare legs shorting together in really dense layouts though.It's really a very efficient technique, since through-hole boards normally require a good bit of vertical space anyway. And it looks cool.
After that, solder the transistors and the screw terminals I got for the outputs, and we're golden.
I'll post again when I get around to doing some test firings with it.
Got to watch out for the bare legs shorting together in really dense layouts though.
Remember that solder follows three things:
- Heat
- Flux
- Other solder
Those that subscribe to the "quick joint is a good joint" approach and using higher heat usually end up with problems of the PCB pads and traces detaching due to the adhesive and PCB substrate not being able to withstand the heat. You might be able to solder it but you might get zero reworks without damaging the PCB irreparably. High heat is not necessary. Normal leaded solder melts at 213degC, and you can solder at about 240degC with a good iron and technique if you are keen. The extra 30degC is needed to give the metals enough energy to form the intermetallic joint that provides the conductivity. I generally run around 280degC, but many would find that too difficult to get good joints with. I am lucky enough to have a good iron. I suggest no hotter than 300degC. That should provide a balance between compensating for poor technique and not being too harsh on the PCB, if you are lucky.I like to use higher heat than most folks recommend... And I try to use shorter duration to compensate. That's just me.... Doing this is "risky", but you can compensate/mitigate the "risk" with techniques....
Got to watch out for the bare legs shorting together in really dense layouts though.
Some good advice in the above post.
Except: <high heat; low duration>
Those that subscribe to the "quick joint is a good joint" approach and using higher heat usually end up with problems of the PCB pads and traces detaching due to the adhesive and PCB substrate not being able to withstand the heat. You might be able to solder it but you might get zero reworks without damaging the PCB irreparably. High heat is not necessary. Normal leaded solder melts at 213degC, and you can solder at about 240degC with a good iron and technique if you are keen. The extra 30degC is needed to give the metals enough energy to form the intermetallic joint that provides the conductivity. I generally run around 280degC, but many would find that too difficult to get good joints with. I am lucky enough to have a good iron. I suggest no hotter than 300degC. That should provide a balance between compensating for poor technique and not being too harsh on the PCB, if you are lucky.
Sounds good! I have seen guys run 350degC and turn up to 400 for when they need a really quick joint .Oh! Well I guess I don't really use THAT high of heat then.
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