BAMF 2600p
- Thread starter Jewjo
- Start date
Jewjo
Well-Known Member
Update for today:
Dremeling takes a lot longer than I recall. The only thing I accomplished today was dremeling out holes for the buttons and screen. I almost did the d-pad too, but I didn't have the patience. Obviously, I won't finish this tomorrow, but hopefully I'll be able to find time and space in my dorm to finish this thing before 2011.
Dremeling takes a lot longer than I recall. The only thing I accomplished today was dremeling out holes for the buttons and screen. I almost did the d-pad too, but I didn't have the patience. Obviously, I won't finish this tomorrow, but hopefully I'll be able to find time and space in my dorm to finish this thing before 2011.
That's some pretty bad news as I planned on using 6 AAs to power the whole thing eventually. Can't I just throw some resistors on the 9V going into the screen?XCVG said:
XCVG
ModRetro Legend
You could throw some resistors inline, but it's not recommended as there are several caveats. First, they will get hot as Heck. Second, resistors don't just reduce voltage- it's dependant on the amperage or something like that. I can't really explain it well, but basically if you change the amperage you are drawing, you change the voltage that gets put out. Third, putting resistors in parallel will allow you to pull more power through without them exploding, but it will reduce the total resistance. I believe it is R1xR2/R1+R2 for two resistors, but I'm probably wrong.
Also, I do not recommend powering anything off AAs, ever. The problem is that rechargables are 1.2V, and alkalines are 1.5V. If you plan to use rechargables, alkalines will most likely fry stuff. If you plan on using alkalines, rechargables won't power it. Six alkalines provides 9V, but six rechargables puts out only 7.2V. Seven will get you a better 8.4V. So unless you have a good flexible power regulation scheme, I don't recommend AAs. If you do use them, clearly label which type to use. Maybe provide a nice switch to bypass one cell? Maybe some sort of autoswitch?
Also, I do not recommend powering anything off AAs, ever. The problem is that rechargables are 1.2V, and alkalines are 1.5V. If you plan to use rechargables, alkalines will most likely fry stuff. If you plan on using alkalines, rechargables won't power it. Six alkalines provides 9V, but six rechargables puts out only 7.2V. Seven will get you a better 8.4V. So unless you have a good flexible power regulation scheme, I don't recommend AAs. If you do use them, clearly label which type to use. Maybe provide a nice switch to bypass one cell? Maybe some sort of autoswitch?
Jewjo
Well-Known Member
Now I feel dumb, I didn't know that rechargeables were only 1.2V. My 6 AAs are rechargeable, but you're telling me now that 7.2V is too few? And from what I understand, you're saying I can't mix it up a little with say, 5 rechargeables and 1 alkaline for a total of 7.5V? I do have two 3.7V Li-Pos with appropriate charger and prot circuit. I couldn't ever get them to work (because I'm incompetent), but it seems that they are my best option other than buying any more batteries.XCVG said:
Man, batteries are my most hated part of portablizing, bar none.
XCVG
ModRetro Legend
Never mix alkalines and rechargables. Just not a good idea.
7.2V might work- it is enough for the PSone screen. It should be enough for the Atari, but the 7805 might be old crap and not be able to take it. If you replace it with an LDO regulator or TI card it would work fine. The thing is, you must never use alkalines in a setup like this. It will fry your PSone screen. Now if you put in a switch to bypass one cell, you could use five alkalines, which gives an acceptable 7.5V.
7.2V might work- it is enough for the PSone screen. It should be enough for the Atari, but the 7805 might be old crap and not be able to take it. If you replace it with an LDO regulator or TI card it would work fine. The thing is, you must never use alkalines in a setup like this. It will fry your PSone screen. Now if you put in a switch to bypass one cell, you could use five alkalines, which gives an acceptable 7.5V.
Jewjo
Well-Known Member
Woah, man, I have no idea what any of that stuff is.XCVG said:
I briefly considered doing something like that, but then I realized that it would end up being too expensive replacing batteries left and right. Sadly, I'm no longer at a point in my life where my parents will buy me batteries whenever I run out.
XCVG
ModRetro Legend
Low Dropout voltage regulators. Usually this term is used to describe a different version or similar alternative that works down to a lower voltage. For example, a normal 7805 may crap out at 7V (just a guess), but an LDO would be good down to 6V (it depends on the part in reality). The term "TI card" is used in the portabilizing community, usually referring to the PTH08080 or PTH08000 but sometimes referring to other TI regulator modules. These are little modules that you can set the output voltage with a resistor. They are switching rather than linear, which means higher efficiency (and by extension lower power consumption), reduced heat output, lower drop out, and higher current capacity.
As for adding a switch, it might be useful just in case. Yeah, you probably intend to use rechargables, because you can't afford alkalines. But what happens if you're in Japan, you don't have a charger, and your batteries are dead? It's kind of unlikely, but possible.
As for adding a switch, it might be useful just in case. Yeah, you probably intend to use rechargables, because you can't afford alkalines. But what happens if you're in Japan, you don't have a charger, and your batteries are dead? It's kind of unlikely, but possible.
