diy portable radio - Page 1
Forum section: electronics / projects

author: shanky887614
author_rank: Contributor
timestamp: May 20, 2015, 07:00:56 am
content: ok long story short.my makita radio broke and im not paying £100 for another when it only lasted a year (it was treated well and Hardly used)anyway i found some info about people that had been making there own radios using an old car stereo.it got me thinking, hmm a radio powered by 12v battery supply in a toolbox, after a bit of searching i realised a few people have used ammo boxes and posted guides.after looking through a few for idea's i came across a drawing so i tweaked it a little bit.what do you guys think of this?im probably going to tweak it a little more because im going to run it off say 18650 cells instead of a drill battery (aa sized but 3ah cells)below is the original drawing i borrowedi just need to pick up a relay to swap between battery and mainsor i might get rid completly and just have it battery powered (will make it simpler)what would be a good way to set a discharge limit? that is one of the things i am looking into at the moment

author: smjcuk
author_rank: Frequent Contributor
timestamp: May 20, 2015, 07:30:48 am
content: That was my hifi when i was a kid. I'd keep it simple and use a sealed lead acid battery in the toolbox with the head unit and just connect a trickle charger to it when you're not using it. Put a 10A fuse inline with the head unit and make sure you have the accessory supply wired up according to the radio instructions. The design above is totally overkill.You can get some decent cheap head units that have USB ports these days as well so they make good stand alone mp3 players.Assume you are in the UK, so hit gumtree.com for all the bits. You can probably do this for 50-60 quid easy.

author: tron9000
author_rank: Frequent Contributor
timestamp: May 20, 2015, 08:36:35 am
content: Quote from: shanky887614 on May 20, 2015, 07:00:56 amI'd have expected more from Makita! But there it is, 1 years warranty:http://www.makitauk.com/service-care.htmljust a few things: remember to earth the metal box and I would keep the charge indicator, ditch the panel meter and somehow compliment another indicator with the charge indicator (e.g. bi-colour LED) to indicate when charge is low, and keep the 12V outlet.ORinstead of the 12V outlet, have a USB port with the power pins connected to a 5V supply, then you could charge your phone off it.The panel meter seems a bit superfluous to your requirements for just a radio, when all you really need to know: is it charging? Does it have enough charge?

author: shanky887614
author_rank: Contributor
timestamp: May 20, 2015, 08:55:06 am
content: Quote from: smjcuk on May 20, 2015, 07:30:48 amto be honest the radio i picked up (a new sony) for £40 has a built in fuse (10amp) on the back so it doesnt need one.thank you for the above postQuote from: tron9000 on May 20, 2015, 08:36:35 amthe top picture is the rough design to what im going to use, the bottom one is the one i borrowed off someone else (i was going to use li-ion batteries to keep the weight down)i might swap it to a couple fire alarm type batteries (sealed lead acid batteries) 12v 7a are quite small so will work well. plus i can use a car charger like you guys recommendedi was looking to get a good 8-10 hours out of it for use at workin truth there is no charger in the uptodate plan. i uploaded a copy that i was in the process of editing stuff out of

author: tron9000
author_rank: Frequent Contributor
timestamp: May 20, 2015, 09:54:27 am
content: Quote from: shanky887614 on May 20, 2015, 08:55:06 amerm, this was on my desk, are you meaning one of these (see attached)?cos I can tell you, it ain't small and it weighs about a kilo!

author: shanky887614
author_rank: Contributor
timestamp: May 20, 2015, 10:01:04 am
content: Quote from: tron9000 on May 20, 2015, 09:54:27 amsorry your right, i was thinking of the 2ah for the physical size1kg is fine for weight and i would rather go for a larger battery.that was one of the reasons i was toying with 18650 cells. there aa size and are 3.7v and 3ah each.the problem if i do go with the 18650 is i will need to look into putting a protection circuit or similar in

author: tron9000
author_rank: Frequent Contributor
timestamp: May 20, 2015, 10:21:18 am
content: 18650 cells are not quite AA sized, but I know what you mean, they are similar but are not compatible, 18650's are bigger by about 25% in length and diameter.http://en.wikipedia.org/wiki/List_of_battery_sizes#Cylindrical_lithium-ion_rechargeablehttp://en.wikipedia.org/wiki/List_of_battery_sizes#Common_battery_sizesI bought some a while ago off ebay for a head torch, and they were pants, utter crap, couldn't hold their charge! Plus the charge didn't cut out automatically, so had to keep an eye on it, was a bit paranoid about them over heating, leaking and consequently burning my shed down! Ironically, the ones I bought were called Ultrafire! Not a good choice of brand name for a Lithium based battery IMO!To get decent one's you will have to shop around, but be prepared to to pay a bit more than the ebay prices.good thing about lead acid is they are easy to charge and are less prone to catching fire if they leak or get damaged.

author: shanky887614
author_rank: Contributor
timestamp: May 20, 2015, 10:52:01 am
content: Quote from: tron9000 on May 20, 2015, 10:21:18 amyou couldnt have picked a worst brand ill post a linkjust one examplebudgetlightforum.com/node/27603to be honest i was going to go for the larger protected cells by say panasonic or sanya etc

author: technix
author_rank: Super Contributor
timestamp: May 20, 2015, 10:58:29 am
content: Here is what came to my head out front: single chip stereo FM receiver. Those chips are cheap, requires very few external components to work, and can be powered by a single 18650 cell for a very long time. Combine one of those with a TP4056-based Li-ion charger/protection chip and you get a working FM radio with internal rechargeable battery.

author: tron9000
author_rank: Frequent Contributor
timestamp: May 20, 2015, 11:13:52 am
content: Quote from: shanky887614 on May 20, 2015, 10:52:01 amwell shheeeettt!would'ya look at that! Bar-stewards!

author: vk3yedotcom
author_rank: Frequent Contributor
timestamp: May 20, 2015, 11:31:15 am
content: Great idea. If you can get a radio with a USB connection & MP3 player. If you're into long distance AM reception you'll find the car radio works better than average. As for the power source I used a split up 24v NiMH battery pack from old medical gear. 4 amp hours should be fine. I use them for other things so the charger is external. But if you've got room for an internal supply maybe put some terminals on it to make it a useful general purpose supply. Or even a charger for cordless drills etc.The acoustics of the box are really important for good sound quality. I built one in an esky (basically 2 x plastic with air cavity). Didn't bother with stereo - just used one speaker. With the lid on (which makes a huge difference) the sound is fantastic. Here's a video:

author: shanky887614
author_rank: Contributor
timestamp: May 20, 2015, 12:21:13 pm
content: Quote from: vk3yedotcom on May 20, 2015, 11:31:15 amvery nice, ill watch when i get home from work.eventually its going to look similar to thisdepending on the sound i might line it inside

author: tron9000
author_rank: Frequent Contributor
timestamp: May 20, 2015, 12:27:44 pm
content: oooohhh, like!Where can you get ammo boxes from? army surplus?

author: shanky887614
author_rank: Contributor
timestamp: May 20, 2015, 01:49:38 pm
content: Quote from: tron9000 on May 20, 2015, 12:27:44 pmyes army surplus and ebay. that is a 50cal Ammo box.they have a waterproof gasket in the lid so very usefulforgot to mention you can get them on Amazon as well

author: shanky887614
author_rank: Contributor
timestamp: May 20, 2015, 08:32:02 pm
content: ok ive had a rethink and this is my new plan (ill add the charger later and might put a 12v car socket in)ive got the case in my car and some old speakers in the garage so as soon as i get the battery and some leads and crimps ill put it together

author: shanky887614
author_rank: Contributor
timestamp: May 20, 2015, 08:32:28 pm
content: mod please delete duplicate

author: BennVenn
author_rank: Regular Contributor
timestamp: May 20, 2015, 08:34:24 pm
content: My girlfriend and I build this little guy up -http://bennvenn.com/TDA7498.htmMore sound than you need and runs from Li-po packs which have low voltage protection and a charger. All in all, pretty cheap and good sound. Does bluetooth, USB, radio and has a remote.

author: tron9000
author_rank: Frequent Contributor
timestamp: May 21, 2015, 07:47:41 am
content: Quote from: shanky887614 on May 20, 2015, 08:32:02 pmDoes the stereo head have the relevant power management controllers already in it? also when plugged in and in use, is it ok to run off the trickle charger? Wouldn't you need a a separate supply when mains powered?

author: smjcuk
author_rank: Frequent Contributor
timestamp: May 21, 2015, 07:52:02 am
content: I'd use the trickle charger as the mains supply as well. Think of the battery as a huge capacitor in function when the charger is connected.Technically this is the same as the alternator charging and providing power when your car engine is running and the battery providing power when the engine is stopped.Schematic above is fine but the battery is a two port device so it makes sense to display it as one.I'd also personally leave the charger and mains outside the unit for safety and so you don't have to carry it around.

author: tron9000
author_rank: Frequent Contributor
timestamp: May 21, 2015, 08:03:34 am
content: doesn't it depend on CC or CV trickle charging?If it was me, I'd go for CV trickle charging and set the output of the charger to about 13V-ish and design it to supply 2A-3A max (shouldn't need much more, unless its a right boom box!), or have I just confused the 2 modes? (coffee still taking affect)

author: smjcuk
author_rank: Frequent Contributor
timestamp: May 21, 2015, 08:20:34 am
content: No idea to be honest. It was a "maintenance charger" akin to one of these:http://www.halfords.com/motoring-travel/bulbs-wiper-blades-batteries/car-battery-chargers/halfords-maintenance-charger- assume they are current limited based on the description.I checked the battery voltage when connected and it was about 14.5v which wasn't enough to cause the head unit trouble.

author: shanky887614
author_rank: Contributor
timestamp: May 21, 2015, 11:26:36 am
content: surely most head units can take an input of 12-18v (maybe 24) just because of how common the battery size is

author: tron9000
author_rank: Frequent Contributor
timestamp: May 21, 2015, 11:37:02 am
content: to get more out of your battery, you wantit to accepta wider input power, 10V or 11V to 18V.EDIT: just re-read and I thought it should be clearer

author: shanky887614
author_rank: Contributor
timestamp: May 21, 2015, 08:40:34 pm
content: hmm, ive just looked up the details of the battery i was going to use and its too big and heavy2.5kg and it takes up a lot of space in there as well, i might have a look at stacking two smaller ones together or go back to the li-ion idea.ill finish rough sketch in sketchup then decide

author: BennVenn
author_rank: Regular Contributor
timestamp: May 21, 2015, 09:01:14 pm
content: http://www.ebay.com.au/itm/DC-12V-6800mAh-Super-Rechargeable-Protable-Li-ion-Battery-With-EU-Plug-Adapter-/161534557672?pt=LH_DefaultDomain_15&hash=item259c35bde8Grossly over rated, closer to 3Ah but has the under voltage protection and a charger. Over current kicks in at 2amps so maybe use two.

author: shanky887614
author_rank: Contributor
timestamp: May 23, 2015, 03:51:38 pm
content: im gutted, ill have to either put the radio in on a slight angle to fit it in.i forgot to take into account the cable connector on the back of the radio. ill either put it sticking through the lid or buy the taller 50 cal ammo box ( i didnt realise they did slightly bigger ones as well)i got a 5ah 12v sealed lead acid battery from a place on the way home that fits perfectly and will allow room for the speakers, i just need to buy the rocker switch off amazon etc then ill be ready to test build it

author: smjcuk
author_rank: Frequent Contributor
timestamp: May 23, 2015, 04:51:01 pm
content: If it's any consolation, the radio in my Fiat is the same; sticks out by an inch i.e. they didn't leave enough room for the cables.And yes it came like that, new...

author: G7PSK
author_rank: Super Contributor
timestamp: May 23, 2015, 04:54:08 pm
content: I find the best source of 18650 Lipo cells is old laptop battery packs. Most of the packs that fail only have one dead cell out of 6 or 9.

author: shanky887614
author_rank: Contributor
timestamp: May 26, 2015, 03:13:05 pm
content: ok this is the case im going to usealong with these speakersill use this battery and i have space for at least another one if i wanted to go overboard with speakers etcradio itself says it has 4x55w outputs (18a ish) but i dont belive that, the headunit has a 10a fuse on it i need to check the paperwork if that is just for the perm L or whatok ive got most parts nowradiobatterycablechargerconnectors etcjust waiting on delivery ofcasespeakers ( got some old ones in garage i can test it with)depending on the sound i might box it in or line it.

author: tron9000
author_rank: Frequent Contributor
timestamp: May 27, 2015, 08:19:04 am
content: How much was ammo tin? Thinking of using one for a low power portable charger/inverter

author: shanky887614
author_rank: Contributor
timestamp: May 27, 2015, 07:29:57 pm
content: Quote from: tron9000 on May 27, 2015, 08:19:04 am£15 there cheap (thats for 50cal ammo box)

author: shanky887614
author_rank: Contributor
timestamp: May 28, 2015, 08:42:45 pm
content: ok, ive finally got the bigger case and im going to change the design again.here is a quick sketchup of the designthis is the front view(top two holes are going to be 4" speakers (100mm across)bottom one i think ill put a 6" in (cause i can)this one below is inside, the big square box at the back is the radio and the smaller one is a 5ah 12v battery (i might swap it to a lot bigger battery now i have the space)(the line across the bottom is how far the 4" speakers stick out, i havent removed that from when i used the same model for the smaller case)

author: tron9000
author_rank: Frequent Contributor
timestamp: May 29, 2015, 09:37:41 am
content: looks good, make sure you don't cut your tweeter holes too close to the lid, otherwise it may not shut. Also remember to take into account for wiring, takes up more space than you think sometimes!

author: shanky887614
author_rank: Contributor
timestamp: May 29, 2015, 12:53:37 pm
content: Quote from: tron9000 on May 29, 2015, 09:37:41 amwill do, im an electrician by trade so im going to be using tri-rated singles for power etc and from experience ive got enough space to stash my charger in there.the amount of space availible will depend on the depth of the speaker

author: shanky887614
author_rank: Contributor
timestamp: June 20, 2015, 10:38:30 pm
content: i thought i should update on progresseverything works and this is the finished look, the aerial aerial is removable and comes out of the back.

author: tron9000
author_rank: Frequent Contributor
timestamp: June 22, 2015, 08:10:41 am
content: looks good. More photos?

author: shanky887614
author_rank: Contributor
timestamp: June 24, 2015, 06:39:14 am
content: ill upload some better ones later when i get home

author: Deathwish
author_rank: Unknown
timestamp: June 24, 2015, 07:36:20 am
content: Why battery powered, why not solar and clockwork wind up ?.

author: shanky887614
author_rank: Contributor
timestamp: June 26, 2015, 04:34:50 pm
content: deathehish because it might spend all day inside besides running off a sealed lead acid battery is very simple.at some point im going to add an external port to charge the battery (i might add a relay or similar in and a transformer so it will run off my 18v drill batteries)i couldnt find the 4mm black pins at the time so i improvised (i have found them now and will use nylon nuts with them)at some point i want to get an iso connector that will fit the radio and do it properly and wire it seperately for the memory (SW+L are linked atm)

author: shanky887614
author_rank: Contributor
timestamp: July 22, 2015, 02:44:00 pm
content: update:ive had it running the odd day and had it going from 8am-3pm (7 hours) constantly at reasonably loud volume.ive got another battery as well now as a spare in there, im going to put a 18v-12v transformer in there so it can run off my makita drill batteries as well.at the moment i recon i have had it running off the one battery for 10hours or so, that puts the running current at roughly 0.5ah.

author: shanky887614
author_rank: Contributor
timestamp: July 25, 2015, 05:22:30 pm
content: another update.ive seriesed up two 12v 5ah batteries to get one 12v 10ah supply, a lead to plug a charger in as well so i can charge it without removing the batteries (900mah charger and radio draws 500mah so all good)ill make a drawing later to explain myself better. (motorbike charger by the way)