Instructables

Low-cost Battery-powered portable widescreen DTV

Picture of Low-cost Battery-powered portable widescreen DTV
Use ordinary D batteries to power a small DTV converter box connected to a portable DVD player or handheld TV.

Last September, Hurricane Ike swept through town and just about everyone was without power for days, unable to get news or weather updates. Being a computer programmer, I have two backup UPS (Universal Power Supply) battery backups that I charged up in advance so I'd have *some* emergency power during the inevitable blackout.

When the storm hit, I was able to power my portable TV for a mere 3 minutes before my UPS was drained. My sister took shelter at a friends' home, who happened to own one of those tiny 2.5" battery-powered handheld TV's. My sister noted how helpful it was (and would be) to have one for emergencies, but I reminded her that after February 17, (now June 12) 2009, that handheld TV would be nothing more than a paperweight, as TV stations went all Digital.

I then started looking online for a portable digital TV, which I discovered all cost between $150-$350. Ouch. That's when I started thinking about just plugging a small DTV tuner into a handheld TV. It wouldn't be as "portable", but I didn't care about "portability", just something to provide TV reception during a blackout. If the TV was powered by batteries, I only needed to power the tuner, preferably using cheap off-the-shelf batteries that I can stock up on the next time a storm hits. And once the Digital switch-over takes place, those old handheld TV's are going to become super-cheap as people find they can no longer use them.

To save even more money, I ordered two government $40 DTV coupons online and (after much research) used one to purchase a "MicroGEM MG2000" Digital Converter Box (the smallest unit made) for the most compact package. The power requirements of the MG2000 is only 6.5v. Hoping I could power it with only 6v (four 1.5v batteries), I also purchased a 4-D cell plastic battery holder (only to discover later it just wasn't enough power).

Mostly, this "Instructable" is just about building a battery pack for the DTV tuner. Everything else is done for you. If you find/have a DTV receiver whose power requirement is an *exact* multiple of "1.5v" (6v, 7.5v, 9v, 12v), you can do all this without "building" anything!

I apologize for not having taken any photos *during* construction, but I didn't think of turning this into a how-to until after I was done.
 
Remove these adsRemove these ads by Signing Up
jpnagle593 years ago
Come on boys, .4-.8 volts makes for not much concern- the box has a filter... Want HDTV? Like Last_Liberal said, it is for emergencies and such. Good thinking LL...if you want HD or Imax, rent a big generator, that way your neighbors can plug into it, and you can charge them for the juice...

Just trying to help here folks, not criticize...

Good point here- if you are expecting to have bad weather that will isolate you from having modern devices that work, rent that generator or buy one as fast as you can...they go fast, very fast...

Here's another tip- if you have a land line telephone, check to see if you have voltage available on the wires. Remove the telephone jack, check yellow/black, and red/green with a meter to see what you have. Here at my house, I don't have a land line telephone, but I still have juice on the jacks. I have a 5, 6, 9, 12 volt regulators already put together with telephone plugs, so I can just plug into the existing jacks to get the voltage that I need.

If you have land lines, and you use red/green on the jacks- make sure you have a regulator, just in case a ring voltage comes down the lines. It can be a larger voltage, and if you are not aware of it- it will cause damage to devices if not handled right...

I used this 'trick' back in 1969 when hurricane Camilla hit the gulf with 210 mph winds. The telephone lines to my house still had voltage, I used it...

Yes, I'm that old....
floryzzz4 years ago
 NOW TURN IT ON (i mean the cooker)
nice thing
ReCreate5 years ago
is there anyway to achieve a perfect 5.0 volts using 1.2 v batteries and 1.5 ones?
a five volt regulator
It outputs 4.98V What a rip off XD
i think it will still work
Oh sure it will work, I figured that out about 3 months after i asked the question, I never knew about regulators before ;)
Ok, but some times you dont get ripped off. i once got a set of AA's. They each put out about 1.8Volts :)
Wow, 1.8?
yes, on a 1.5v battery
Weird...
You dont need perfect 5 volts, most devices are designed to be able to work with a little bit more or a little bit extra voltage
Yes but more than .8 of a volt could kill them, and less that .8 of a volt and they could malfunction...
That all depends on what you are working with, I am running three camera charger boards on 12V, they are designed to work with 1.5V.
You are overpowering a camera by 10+ Times? That is truly amazing, Show me a picture of the setup if it is true.
HELLO?
Last_Liberal (author)  ReCreate5 years ago
Doing the math, four 1.2v batteries would give you 4.8v, which *might* suffice, but my experience has been "just over is better than just under".

If you have access to 1.2v cells, I'd recommend three 1.2v batteries plus one 1.5v battery for a total of 5.1v. That's as close as you're going to get.
Thanks man it worked
4x 1.5 will be fine as said below.
Thanks
ahhh also with the rechargeable batteries i stick them in the fridge after charging them for me they last longer
flag them if they say something mean u are trying to help them dont take their rudeness and i meant to reword what i wrote but im buzy and lazy
Winegard RCDT09A they made that for portable tvs..................................
Flea5 years ago
You should take the words HD out of the instructable. Portable HD media players costs over $400 which I wouldn't consider low cost. You shoul replace it with LCD. Or change the title to "Low cost battery powered HD tuner". Otherwise, it's very misleading. I'd also recommend using rechargable batteries. They're 1.2V, so 6 rechargables would give you 7.2V. A little closer to the 6.5V used by the device. Plus, you'll save money on batteries and the environment :). All in all, a nifty idea.
Last_Liberal (author)  Flea5 years ago
Please note that my use of "HD" was responded to below. Only your choice of display affects the quality of the output. While I chose a portable DVD player, if you used an LCD monitor, you could get full HD (good luck powering it on batteries for more than a few minutes though).

On the use of rechargeable batteries, as my goal was to have a battery powered digital TV in a weather-related blackout following the February DTV switchover, one would be hard pressed to recharge NiCad's once the power went out... especially since NiCad's last about 1/3 as long per charge as alkaline batteries do.

While NiCad's may *start* with a higher charge, that charge *quickly* dissipates, and the receiver I chose fails to work without at least a steady 6.5v of power.

Thanks for the feedback and kind words.
NiCAD batteries are old technology. They do not store much power, but their discharge rate (as with NiMH) is much more stable than Alkalines. Below are graphs of NiCAD discharge rate and NiMH+Alkaline discharge rates. Rechargables provide a much more stable voltage. The main problem with rechargables is that they lose a signifigant amount of charge if you store them for long periods. Thankfully, this is the problem Sanyo's Eneloop battery solves (hey, they're sponsoring this contest, might as well promote them). Eneloops should retain about 80% of it's charge after a year of storage. They should also power your portable DTV for a longer period than Alkalines.
nicad_test.gifnimh_vs_alkaline.gifnewgraph.gif
Last_Liberal (author)  Last_Liberal5 years ago
(Since it appears to be an issue, I changed the title to "DTV" instead of "HDTV".)
your a genius!!!! now i might do this to doggie-t.v.
DanAdamKOF5 years ago
Pretty cool, but this isn't really HD if you're hooking it up through composite. Should still look pretty sharp though.
Last_Liberal (author)  DanAdamKOF5 years ago
Well, technically, it's only standard SD (480p) resolution, limited only by my choice of display. The tuner I chose is capable of full 1080i/p, so a higher rez screen can indeed do full HD. The DVD Player I used is capable of supporting true widescreen video, though the second Player I tried was not (yes, I checked the Player's settings), merely stretching the video, thinking it was on an ordinary 4:3 monitor. :(