Riser helmet mods

Friday, January 13th, 2006

For the snowboarder in all of us, I’ve been working on the ultimate ski/snowboard personal voice communications system.

The idea is to get hifi music, handsfree cellphone conversations, and walkie-talkie radio access all neatly integrated. I would like to be able to go boarding, listening to my music, and receive a call without fumbling for the phone (of course, the phone is optional for those days when silence is golden). Then I would like to be able to talk to my buddies on the other side of the valley without reaching into a pocket for the walkie-talkie.

I looked around on the net and found a partial solution: The Giro Fuse helmets with what they call “TuneUps”. This fits my standard Fuse helmet and does allow for music and a walkie-talkie OR cellphone, but won’t handle all three at the same time. Also, it has one of those tiny little microphones-on-the-string that will produce verage sound and be a pain to activate in thick gloves. I need something a little more industrial. Maybe not throat-mic industrial, but something tougher definitely.

A little more research took me into the motorcycle world, I thought perhaps something like this might exist for bikers. And that led me to the StarCom1, a cool little device that does almost exactly what I need. It supports two headsets (one for the driver and one for a passenger) which is a bit of a waste in my case, but everything else is perfect.

Placing the order was a little confusing. Their site could be better laid out in terms of the kits and the options. But the company was really responsive and both sets arrived promptly. We need to do some custom installation magic, fitting this gear to skiing helmets rather than the usual biking kit for which it is designed, and we will need to setup a special box for the comms unit, the battery pack (I still don’t know how I’m going to create a 12V battery).

This evening Marianne and I got the first part of it done. We had to slice open the neck and ear padding on the helmet. The microphone is on a flexible boom, so the tricky part was figuring how to attach that to something that is basically made of sponge. I was going to try to superglue a piece of rigid plastic to the frame of the ear padding, but Marianne suggested just stitching the boom straight to the fabric. That seemed to work fine. The earpieces fit in nicely, and I glued the PTT (“push-to-talk”) button to the outside of the right ear cover. Doh, I glued in the place where the chinstrap comes down from the helmet, but it’s fine and the helmet fits snugly.

So now we have one modded helmet with the microphone and speakers in place and two cables hanging out the back. So far, I’ve tested the cellphone connection and music interface and it works perfectly. The walkie-talkie isn’t, yet, perhaps there’s some incompatibility between the cable and the radio. Will look into that next week.

The big issue right now is power. The device needs a 12V supply. I have the connector cable, I just don’t have anything to connect it to. On a bike, there would be a 12V supply handy, but I guess I will need to make up some sort of battery pack. Anybody know how to do that? Where can I get a battery pack into which I can plug 4 normal 1.5V batteries in series to make up 12V, and get a simple cable out? Any and all suggestions welcome.

46 comments:

  1. Matthew Saunders says: (permalink)
    January 27th, 2006 at 8:52 pm

    I’m not sure how your getting on with the power issue, but I was wondering if this would help.

    You can get battery holders that hold 8 x 1.5 volt batteries in a 2 rows of 4 cells configuration to make the 12 volts. This would be quite small for your purposes. An example of the holder can be found here: http://www.maplin.co.uk/module.aspx?ModuleNo=31427

    Depending on the power consumption and the time you want the system to work for between battery changes/charging, maybe using either C or D size batteries might be the way to go. Using Alkaline batteries would ensure the longest times. A ‘project box’ could be found to match the size of the battery holder, or some sort of soft bouncy cushion case would be good. You don’t want to fall on it – it’s gonna hurt!

    To go a little more extreme, how about a small 12 volt sealed rechargable lead-acid battery. If you can find a small enough one thats also quite light, this will give much longer usage times and they are cheap so you could have a spare. Your not going to find any of these in the mountain shops, but if you plan the connecting cable to the battery holder/pack so that you can interchange packs – those AA or C size batteries could be used in emergency. An example battery can be found here: http://www.maplin.co.uk/Module.aspx?ModuleNo=27088

    If you want to go a step further with the sealed lead-acid battery, why not take along a solar charger? You probably wouldn’t want to take it down the slope but if you can stash it somewhere at the bottom, a battery could be charging whilst you are using the other battery or whilst you are having lunch etc. You can get solar panels that will trickle charge a 12 volt lead-acid battery that are only 352x125x14mm in size. An example can be found here: http://www.maplin.co.uk/Module.aspx?ModuleNo=47902

    Hope this helps. Good luck with the project.

    Matthew

  2. Ankur Dasgupta says: (permalink)
    January 31st, 2006 at 11:38 am

    Hi mark,
    Just read about your efforts, i had a busines sidea, if you feel this is worthwhile, maybe this can be another of your efforts to make viable products available to the people.
    The philosophy behind it: Most of the working class, mainly in the technology area are gizmo freaks: cellphone, laptop, digital camera, camcorder. And many times we have more than one of the same product eg 2 cellphones. The problem faced is how to ensure the battery is in a running condition – we often forget to charge !!
    so what we can do is make a product, resembling a spike buster, which have 5 power points, that can be programmed to switch on and off on a pre-defined interval. the benefit is that the battery chargers of these gizmos can be connected and left connected to ensure a periodic charge which will ensure any of the equipment is always ready to use.
    Pls let me know if you liked this idea, and of course, if you do want to make something from this. I would be delighted to be kept in the loop of the happenings and its launch, will be my pleasure to know that an idea of mine works :-)
    Thanks
    Ankur

  3. Iaan says: (permalink)
    January 31st, 2006 at 12:21 pm

    Perhaps one can get a 12V battery pack, made for radio control cars. These are rechargable, and lightweight.
    Any radio control shop should stock them.

  4. Emil says: (permalink)
    January 31st, 2006 at 1:06 pm

    Uh, Mark, I guess it’s a typo, but I wouldn’t expect to be able to find *any* mere battery pack that manages that feat. Four 1.5 V cells won’t give you more than 6 V, perhaps a little more when the cells are really fresh. To reach 12 V, of course, you’d need eight cells. It’s possible that 12 V could be reached from a lower initial voltage, using electronics, but that might be cheating. Also, you didn’t post any numbers saying how much current the devices need, which makes it even harder to know what’s going to work. Oh well. I’m not an EE, just another CS with a soldering iron, but thought I’d point that little calculation oddness out. I hope you find something.

  5. Dinda says: (permalink)
    January 31st, 2006 at 11:51 pm

    http://www.radioshack.com/search/index.jsp?kw=12v+battery&f=Taxonomy%2FRSK%2F2032152&categoryId=2032152&kwCatId=2032056&cp=2032056

    Will one of these work? I suspect eBay might be another source – The “BatteryGuy” on there is a great source of hard to find batteries. If you can’t get one delivered to where ever UB these days I’m sure I can arrange to mail you one. Otherwise I can ask my real ‘geek’ friends on how to jumper the 4 smaller ones together.

    Glad to see you’re finally updating the site more often!

  6. Dave D says: (permalink)
    February 1st, 2006 at 3:19 pm

    Hi,

    [Arrived here after a random surf following Ubuntu trail.]

    Ok, I’ll bite – my 5 cents worth, after skimming:

    Are you sure you need external power?
    Looking at , it appears to have built-in 9V battery.

    But an off-the-top-of-my-head response to your battery-pack questions:
    I’d suggest buying a premade battery pack – less hassle.
    Things to consider:
    * terminal voltage (StarCom manual indicates acceptable voltage range of 10V to 15V DC)
    * capacity (current x time) [not sure how much current this StarCom thing draws(?)]
    * weight
    * temperature considerations

    So for example, something like
    http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=1329
    is a possiblity. 5.2 ounces is ~150g, which is pretty light. Not sure if the capacity is enough. Voltage is 10.8V which is in range (could always go up to 14.8V — http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=1975 ).
    They also have a link to a universal charger.
    Lithium-Ion batteries are light, but I wouldn’t know if there are temperature or other considerations.
    Another option would be NiMH ??

    If you know a tame elec.eng. they’ll sort you out.

  7. Dave D says: (permalink)
    February 1st, 2006 at 3:34 pm

    Hi,

    [Arrived here after a random surf following Ubuntu trail.]

    Ok, I’ll bite – my 5 cents worth, after skimming:

    Are you sure you need external power?
    Looking at , it appears to have built-in 9V

    battery.

    But an off-the-top-of-my-head response to your battery-pack questions:
    I’d suggest buying a premade battery pack – less hassle.
    Things to consider:
    * terminal voltage (StarCom manual indicates acceptable voltage range of 10V to 15V DC)
    * capacity (current x time) [not sure how much current this StarCom thing draws(?)]
    * weight
    * temperature considerations

    So for example, something like
    http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=1329
    is a possiblity. 5.2 ounces is ~150g, which is pretty light. Not sure if the capacity is

    enough. Voltage is 10.8V which is in range (could always go up to 14.8V —

    http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=1975 ).
    They also have a link to a universal charger.
    Lithium-Ion batteries are light, but I wouldn’t know if there are temperature or other

    considerations.
    Another option would be NiMH ??

    If you know a tame elec.eng. they’ll sort you out.

  8. Dave D says: (permalink)
    February 1st, 2006 at 3:37 pm

    Hi,

    [Arrived here after a random surf following Ubuntu trail.]

    Ok, I’ll bite – my 5 cents worth, after skimming:

    Are you sure you need external power?
    Looking at , it appears to have built-in 9V battery.

    But an off-the-top-of-my-head response to your battery-pack questions:
    I’d suggest buying a premade battery pack – less hassle.
    Things to consider:
    * terminal voltage (StarCom manual indicates acceptable voltage range of 10V to 15V DC)
    * capacity (current x time) [not sure how much current this StarCom thing draws(?)]
    * weight
    * temperature considerations

    So for example, something like
    http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=1329
    is a possiblity. 5.2 ounces is ~150g, which is pretty light. Not sure if the capacity is enough.
    Voltage is 10.8V which is in range (could always go up to 14.8V —
    http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=1975 ).
    They also have a link to a universal charger.
    Lithium-Ion batteries are light, but I wouldn’t know if there are temperature or other

    considerations.
    Another option would be NiMH ??

    If you know a tame elec.eng. they’ll sort you out.

  9. Dave D says: (permalink)
    February 1st, 2006 at 3:40 pm

    Oops!

    Apologies for multiple posts — originally tried from Mozilla (twice), didn’t seem to be working, so tried from IE.
    But now I see three.

  10. Carthik says: (permalink)
    February 1st, 2006 at 11:09 pm

    Nice surprise with the blog, Mark. Thank you for everything, and it’s good to see that you chose to use WordPress, a fine open source blogging tool, over other options.

    Keep on blogging.

  11. Colin Brayton says: (permalink)
    February 2nd, 2006 at 1:18 am

    Decadent! If you get it working, it would nice for bicycling through the park, though won’t it look kind of, er, dorky? I guess the fashion angle comes later.

    I actually came by to congratulate you prematurely for all the ‘Goobuntu’ speculation. Good PR for the ‘buntu brand, which I use and love and proselytize with fervor: I gave away 5 CDs down in Brazil recently. Will users have to start distinguishing between Goobuntu and Trubuntu? A name with lots of U’s in it turns out to have been a nice choice!

  12. raul says: (permalink)
    February 2nd, 2006 at 5:08 pm

    Hello Mark. My name is Raúl Sanchez. I am he gives Bilbao Spain. I love the computer one and mainly Linux in short Ubuntu. My problem is that I don’t have economic resources to be able to buy a PC. Will No have an old PC for my and to be able to job with LINUX?

    He would thank it to you he gives all heart.

    Thank you.

  13. Bernhard Kainz says: (permalink)
    February 3rd, 2006 at 1:41 pm

    Hi,

    I’ve read something about a burtonjacket and cap with integrated bluetooth port. It’s called “Audex Protective Gear”. You will find it at: http://www.audextech.com/. The bad thing is that it’s really expansive.

    Greetings from Munich, Germany…

    Bernhard

    p.s.: Keep on working and supporting ubuntu. Really great software….

  14. Robin Gilham says: (permalink)
    February 6th, 2006 at 2:57 pm

    Hi Mark,

    The easiest is to get the battery pack that takes those small penlights – they have a 9v type clip on connector on the top. Get a 9V connector at the same time and you will have a cable to give you 12V. If you are in Cape Town, Communica would be the place, else you could try Maplin or RS components in the UK. I used a similar arrangement to power my PS2->Palm Vx keyboard interface while backpacking arround South America with my wife, Nicci, for six months – so it should be robust enough. Enjoy the skiing!!

  15. thebugis says: (permalink)
    February 7th, 2006 at 6:24 am

    It’s interesting to see all that you have done, all I can hope for is that your intentions are true and will remain true to the cause. Now back to your post, keep us posted on this project, it’ll be interesting to see if you can manage to combine all three functions into one. All the best!

  16. sunoindia says: (permalink)
    February 7th, 2006 at 1:48 pm

    thanks for making the best os – ubuntu. we need it more and more. ubuntu is great. superb!

  17. Martin says: (permalink)
    February 7th, 2006 at 11:08 pm

    Man, sounds like you´re having fun ! Great !

    I enjoy your work…

    -When do you come down here in Dominican Republic ???

    We are starting to realise the whole open source thing, and we need someone like you because of your stature. Here, it s a bit like Africa, but latino…

    I am in Las Terrenas, which is a tourist area…

    Visit anytime, you might want to adapt your headphones to use it on a kite-surf !!!

  18. Marko says: (permalink)
    February 12th, 2006 at 6:58 pm

    You’ll need 8x 1.5v batteries in series to get 12v!
    I would look for a dry-cell scooter battery, they’re pretty small and lightweight, unlike their lead-acid counterparts.

  19. Michael Goulde says: (permalink)
    February 13th, 2006 at 7:14 pm

    Mark – why not use this 12V battery?

    http://store.batteryspecialists.com/du21malba12v.html

  20. ajs says: (permalink)
    February 14th, 2006 at 5:13 pm

    You will need to use ten 1.2V cells in series to get 12V, though you may find you can get away with just 9.6V {8 cells}, or maybe even 7.2V {6 cells}. You can get battery holders from somewhere like Maplin Electronics. First of all you need to choose what size cells you are going to use. To do this you will need to know how much current your appliance draws. The capacity of batteries is measured in amp-hours, 1Ah = 1 amp * 1 hour, or 100mA * 10 hours, or 4 A * 15 mins. So if your appliance draws 75mA, then a 1.5Ah battery will last for 20 hours. AA size cells are rated about 1.5-2Ah, C and D size about 3-4Ah. Other sizes are available with solderable metal tags attached, for building up custom packs — but then, you won’t easily be able to use disposables in an emergency. This may be important., depending upon whether the appliance is survival-critical or not.

    Wiring cells in series adds up the voltage, but does not change the amp-hour capacity. Wiring cells in parallel adds up the amp-hour capacity, but does not change the voltage.

    For recharging, you will need a power supply which puts out a little more than the battery voltage, and a series resistance to limit the current. The resistor value can be calculated using Ohm’s law: R = (Vpsu – Vbatt) / I. The current I should be the amp-hour capacity of the battery pack, divided by the time in hours for a full charge. So if you have 1500mAh cells and you want them to be fully charged after 10 hours, then I = 150mA = 0.15A. The resistor will get hot. The power it dissipates is given by P = V * I, where V = (Vpsu – Vbat) and I is whatever you calculated. You can use series or parallel combinations to get the exact value.

    Note; all the cells you use MUST have the same amp-hour rating, although they need not be the same make. For example, you cannot use a mix of 1.5 and 1.7Ah batteries in the same pack. Also, the power supply you use as a charger MUST be able to supply the current you are asking for; and remember that most have an internal resistance which must be taken into account, the voltage seen at the terminals will fall as you approach the maximum rating. Get an AVO, and experiment a little.

    Example: we have a PSU which measures 13.2 volts; and a 12V battery pack rated 1.5Ah, which we want to charge in 10 hours. The charging current will be 0.15A and the voltage dropped across the charging resistance is 1.2V. So R = 1.2 / .15 = 8 ohms, the nearest available value is 8.2 ohms which gives us 0.146A — close enough. And the power dissipation is 1.2 * .146 = 0.176W. So a 0.25W resistor will be fine here.

  21. Shermozle says: (permalink)
    February 14th, 2006 at 5:27 pm

    Maybe you can just go straight for 12V batteries in parallel? Certainly would seem more flexible. Try this from Maplin:
    http://www.maplin.co.uk/Module.aspx?ModuleNo=31508&criteria=12V%20battery&doy=14m2

    Depends on how much power you need to draw, as these look rather small.

    Was out snowboarding in France last week. Conditions were crap but improving by the end of the week. Very jealous you’re heading out :)

  22. Björn Bringert says: (permalink)
    February 14th, 2006 at 5:31 pm

    To get a cheap and simple portable 12 V supply, I’d probably use standard rechargeable NiMH batteries in a battery holder. Since NiMH batteries give you about 1.2 V, using 10 of them should do it. A simple battery holder such as this one: http://www.elfa.se/elfa-bin/dyndok.pl?lang=en&dok=206875.htm along with the right connector should be all you need. These things should be available from pretty much any electronics supplier.

    A good NiMH R6 (AA) battery gives you over 2000 mAh at 1.2 V, which means that 10 of them will give you about 24 Wh. If this isn’t enough to power your equipment for a whole day, you could step up the battery size. One nice feature of this approach is that if you run out of batteries, you can just buy some standard R6 batteries from any store in the world (assuming that the equipment can handle getting 15 V instead of 12 V).

    Another alternative if you need more power would be to use a laptop battery. A quick web search got me this: http://www.sarrio.com/sarrio/12voltlaptop.html , an external lithium polymer battery which gives you 90 Wh at 12 V and weighs 3 lbs.

    Since you mention motorcycles, you could get a motorcycle battery, but that seems a little suicidal, what with them containing sulphuric acid and all.

    If you are going to go snowboarding with a big battery pack, you may want to keep it safe from impact and short-circuiting. Shorting even standard R6 NiMH batteries can produce a lot of heat.

  23. Justin Seiferth says: (permalink)
    February 14th, 2006 at 5:32 pm

    Mark,

    There are several 12v Lithium Ion rechargeables on the market- they are relatively expensive but long-lasting and work well in cold weather and very well if confined in clothing where the body will keep them relatively warm (although you cannot charge them in the cold). Here’s an example http://www.pinecomputer.com/pinecom/relibapays.html. I wouldn’t recommend ganging Alkaline or Nickel Metal Hydride; they suck in the cold.

  24. jkinz says: (permalink)
    February 14th, 2006 at 5:37 pm

    two 9 volt transistor batteries in series followed by a resistor to step voltage down should work and makes smaller package

  25. Tony says: (permalink)
    February 14th, 2006 at 6:43 pm

    Mark, I am reluctant to post such an obvious answer to your question, but you can buy a holder for “n” batteries at Radio Shack, and wire them up in series or as you wish. :-)

    best to you,
    tony

  26. David Goodger says: (permalink)
    February 14th, 2006 at 8:02 pm

    4 1.5V batteries make 6V; can’t you just use 8 1.5V batteries to make 12V?

    What kind of current does the StarCom draw at 12V? That might be the more important factor, determining what size batteries you’ll need to get decent life out of them.

  27. max stevens-guille says: (permalink)
    February 14th, 2006 at 9:18 pm

    Mark,

    Check out http://www.batterygeek.net/digital-camera-battery-packs-dvd-batteries-6-12-44.htm

    One of the most commonly preferred features of our BG 6-12-44 DVD battery is the tiny dimensions and light weight. It is about the size of a deck of cards and just a little thicker at 2.25 inches long by 3.25 inches high by 1.5 inches wide. It weighs about the same as a 12 ounce can of Pepsi. Also, it comes with a free leather case with a belt clip and even a free handy car charger adapter so you can recharge your DVD battery anytime when you’re on the go in any automobile.

    Seems to be able to provide 12v / 44 watt hours.

  28. Niels Mache says: (permalink)
    February 14th, 2006 at 11:37 pm

    Hi Marc,

    you may use two Sony NP-FM50 M Series InfoLITHIUM batteries (or similiar batteries) in series. This is convenient because you can re-charge the batteries with a standard camcorder battery charger. The NP-FM50 voltage is 7.2V.
    Two of them are 14.4V which is a perfect 12V motorcycle replacement. You can also try a singe battery. Eventually the communication system works with a single battery (7.2V)

    The Sony NP-FM50 is available for £10-20. On Amazon:
    http://www.amazon.co.uk/exec/obidos/ASIN/B00005K4LY/qid=1139959347/sr=2-1/ref=sr_2_3_1/026-8997356-1108422

  29. Mat Cook says: (permalink)
    February 15th, 2006 at 1:30 am

    You’ll probably need 8 x 1.5v batteries for a total of 12v. I’m guessing you’re thinking of the AA/Penlight size?

    Good electronics stores will sell the packs you would need, this is an example in the uk:
    http://www.maplin.co.uk/module.aspx?TabID=1&criteria=battery%20box&ModuleNo=31427&doy=15m2

    It might work better with a number of 2 or 4 cell battery holders in series (rather than one big 8 way block), so that you can make something that fits comfortably on a belt or shoulder strap.

    Rechargeables would probably work best, especially as the current requirements might be fairly high (especially if it expects a connection to a bike). NiMh batteries are endothermic on discharge so you won’t risk the batteries getting hot (on the other hand, if you’re snowboarding you might appreciate the warmth…)

    Regards,
    Mat Cook

  30. Andreas says: (permalink)
    February 15th, 2006 at 4:18 am

    You’ve probably figured it out by now, but the following battery pack may be what you’re looking for: http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=2357

    Best of all it’s rechargeable! :-)

  31. El says: (permalink)
    February 15th, 2006 at 5:24 am

    Hi Mark,

    I’m sure you solved the problem. But if you do have Radio Shack out there in London then perhaps something like this: http://www.radioshack.com/product/index.jsp?productId=2062244&cp=&kw=aa+battery+holder&parentPage=search

    will do the trick (ok – it’s part of the solution).

    Take care and happy boarding.

    El

  32. Peter Fedorow says: (permalink)
    February 15th, 2006 at 7:21 am

    4 x 1.5V = 6V, you need 8 cells for 12V with regular alkaline batteries. With rechargeable you’ll probably want 10, as they put out about 1.2V instead of 1.5V.

    Personally, I wouldn’t want to have to mess with so many batteries on the slopes. For a prototype I would go with 2 9V batteries in serial and a 7812 (12V) regulator IC from Radio Shack. If that gives enough run-time, then use a DC-to-DC converter, powered off of either 1 or 2 9V battery. 1 battery into a DC to DC converter will reduce your run-time some over the 7812 with 2 9V batteries, but it will be more convenient. If that makes the run-time too short for you, then keep it with 2 9V. The DC-to-DC converter will give you longer run-time, because it doesn’t regulate down the voltage by throwing away, (turning into heat,) the energy dissipated by reducing the voltage from 18V to 12V.

  33. Kevin says: (permalink)
    February 15th, 2006 at 12:52 pm

    Interesting idea: I would add another device, a helmet cam which comes with a 12V rechargeable power source. I use Viosport helmet cam to make my ski/snowboard podcast.

  34. Thomas Black says: (permalink)
    February 16th, 2006 at 1:01 pm

    There are standard battery housings available for this sort of thing, a electronics or hoppy shop would be able to help. My suggestion would be to rather go for a pack of NiMH batteries and have them spot welded together and shrink sealed. That wasy you can try and sew them into a jacket pocket or similar. You can then use the same cable for power out to use for charging. Of course finding the right kind of charger is another problem.

    On that note, I wonder about voltage – if this system was meant for a bike, as in motorbike, it probably has built in capacitors and voltage regulators to balance out the uneven power supply you get on a motorbike. In that case you may need a surplus of voltage to keep everything happy. Eh, 4 normal 1.5 batteries in series to get 12V? That’s 8 by my calculation. To have a surplus, you may be talking even more (NiMH are also only 1.1V). That’s a lot of batteries, it may be worthwhile looking for something in the 12V Lithium variety.

  35. craig says: (permalink)
    February 16th, 2006 at 6:03 pm

    Instead of creating a custom battery pack, would it not be easier to mod the power out on your phone/ipod/walkietalkie to power the Starcom?

    Alternatively have a look at getting an iPod battery booster and trying to use the power out from the booster to power the Starcom. A search on Amazon should find it – think it’s called Nyko iBoost Battery Pack.

    Otherwise check out . There appears to be a handy sized power pack there but it is possibly the worst site in the world. It also doesn’t look to tough to build if you are bored one day :-)

  36. David says: (permalink)
    February 18th, 2006 at 1:08 am

    Hi Mark,

    I enjoy your blogs and other content that you have brought to the web. I must say that you are one who inspires us out there (well at least myself) for the things you have achieved and the ongoing work that you are putting in. Keep it up.

    Just something that may interest you about your wonderful idea for the slops, if you have seen this already then please forgive me but something I remember listening to on Stuff Mag’s Podcast and just done a search for it . . . http://direct.motorola.com/hellomoto/audex/audex_jacket.asp

    It all your needs in one, well almost I think, maybe not the two way walkie talkies but close enough.

    David.

  37. Juan Sebastián Narváez says: (permalink)
    February 18th, 2006 at 4:40 pm

    For an in-series connection perhaps the easiest would be a cylindrical receipient, like that of a flsh light, and have a wire sticking out from each end, fitted with suitable spring loaded caps. There are commercial ruggedized, water tight flashlights that could serve as a model or as starting material for your project.

  38. Will says: (permalink)
    February 27th, 2006 at 6:20 pm

    There are a number of universal rechargeable Li-ion packs available. I’ve used them for various wireless camera devices etc.
    An old laptop battery pack is thin, removable, rechargeable and generally 12V.
    O’niell are making solar back-packs (much trendier but only likely to produce about 3-4W)
    Otherwise a bag full of potatoes connected with stolen Telkom wire worked in school…

  39. dmflad says: (permalink)
    February 27th, 2006 at 7:53 pm

    Maybe look into radio control(R/C) airplane or car set ups using LiPo(Lithium Polymer) batteries. Seems the packs keep getting larger and with the newer larger electric motors guys have been able to retrofit their gas-powered R/C airplanes to electric. No idea about battery time. Shot in the dark, but hey you said any suggestions.

  40. bbm says: (permalink)
    February 28th, 2006 at 11:28 am

    You need to make use of solar power. O’Neil already has a bag available. Why not build it into your ski jacket, as you wouldn’t always want to carry a bag. I guess this means you would need a battery of some kind and would be using solar energy to recharge it.

  41. j-a-p says: (permalink)
    March 18th, 2006 at 11:53 pm

    I think you’ll find you need 8no 1.5v batteries connectied in series to get a 12v supply.

  42. Eirik Hjelle says: (permalink)
    March 19th, 2006 at 2:18 pm

    As you proparbly already know you 4xAA 1,5V batteries in series produces 6Volt DC and since you are looking for 12VDC you’ll need a converter circuit. I did a quick browse through the internet and found a fairly easy circuit which I think will serve the purpose you are looking for, http://www.aaroncake.net/circuits/6-12conv.htm . I found a batteryholder for 4xR6 (AA) batteries for you at http://www.elfa.se/elfa-bin/dyndok.pl?dok=7385.htm . Hope that can help you :)

  43. Jens Kristian Egsgaard says: (permalink)
    March 21st, 2006 at 4:21 pm

    Hi Mark
    If you still have problems with the power supply, I belive you should try use 8*1.5V batteries in serie; that should produce the voltage on 12V. If you only use 4, you will get only half the voltage and you would have to use a transformator, which will be a problem with direct current (and wouldn’t be handy, anyway).
    Regards
    Jens Kristian Egsgaard

  44. ULrich Wilsenach says: (permalink)
    May 25th, 2006 at 7:22 am

    The standard security Remote control batteries (smaller than AA) runs at 12V… simply wire in parrallel to get life you require..
    available at any camera and security products store..

  45. brocly says: (permalink)
    June 12th, 2006 at 10:36 am

    Great job guys…

  46. arai motorcycle helmet says: (permalink)
    December 17th, 2006 at 12:07 am

    Doesn’t it seem like all blogs are narrow down the center of the screen like a newspaper column? Does anyone besides me miss full page, full sized websites that don’t feel all boxed in? I would like to take a poll and see what everyone thinks about this. I think it is possible to make a full screen blog that doesn’t look bloated or stretched; check out my blog and see what you think. Is it too horrible and should I scrap it for an HTML site?