Pages

26 September 2011

028 - DIY prototype of an iPad 2 holder for car glove compartment


  • Prototype of a DIY iPad holder for car glove compartment. © Øyvind Teig, 2011
  • Disclaimer: The holder may destroy the iPad, and its use may be dangerous in the car. On the road it must be used by a passenger, not the driver. This is not a general iPad mounting device for dashboards.
  • You may have a car with a glove compartment where the suggestion described here is impossible, no matter how much you tweak it!
  • There are lots of non-prototype, well developed, off the shelf holders to buy out there! (Like http://www.tabletbite.com/top-ipad-2-car-mounts-chargers-and-car-accessories-2149/)
  • Created 23July11, updated 9April12
The need

We recently bought a new car, but navigation and an advanced music system we purposedly left out. Good sound and an aux input was all we required, which the standard system did deliver. None of us use the car every day since we work within walking and cycling distance from home. And we thought that no matter how modern or advanced any such system would be today, a year or three from now it might not be that glamerous. Also, we had an iPad 2 that we thought could be used in the car.

So, we went for the passenger glove compartment. To my delight I saw that there were some clips, probably meant for a pencil, but could also hold the iPad 2 - which sits beautifully in the bottom of the compartment. This would be a "lower" position (picture below, inset, right).

I used a kitchen type rubber band for a 100 km travel test, and I quickly saw that the flexible grip it gave, was perfect. I attached the rubber band in the top glove compartment lock ring, made of metal. The iPad fell nicely into position, horizontally, and did have a place to lean to on the back, top edge. The volume control in the top had free space above it.

It was also possible to place the iPad in the lower lock mechanism, in an "upper" position (main picture below, and inset, left). In both positions, the screen was easily readable from the driver seat, and the passenger (me or my wife) was eaily able to handle the touch screen, as well as the side buttons. And it didn't feel to take away much foot or leg space.

Also, a cable between the headphone output and aux input connected the iPad with the car, as we didn't buy blue tooth in the car. Most importanly, the integration between the iPod music and the Navigon navigation apps works fine. When "the lady" tells us where to drive, the music is faded. And: the GPS did work like a dream, it seemed to see the satellites. We were on the road of the navigation screen all the time.

Additionally, with a better holding mechanism than a kitchen rubber band, it could probably be made rather secure. However, see disclaimer above and in the pictures.

Aside:
Charging an iPad in the car ::
- Battery life is enough for a long day's driving.
- However, being able to continuously charge on the road still feels quite ok. For us : with navigation and music running, with the iPad 3.5 mm ear phone or sound output connected to the car's music system's aux input. The first solution is mentioned below, but it made too much electromagnetic (EMC) noise in a "ground loop", so it's useless.
- We ended up with a Kensington PowerBolt car charger. It delivers 5 V (Volt) voltage at 2.1 A (Ampere) current required by the iPad. There is not hearable EMC. So it must be a switchmode (switching mode DC/DC) power supply, even if I can only assume that from my calculations below. I mailed Kensington support, and they replied that this information was not available. Fair enough, but I still think it's a switch mode power. Kensington also has a PowerBolt Duo, which delivers two USB 5V outputs, at 2.1 and 1 A. At full load for half an hour, busy charging an iPad anf an iPhone at the same time, it heats up to 60-65 DegC in our car - since I could touch the metal parts, but not for too long. This rather low temperature and assumed heat removal from the contact, strengthens the switch mode case: the Wattage loss could not be 3 A * (14-5) = 18 W, as it would have for a series regulator. But I am only 65% sure!-) As an electronic engineer I'm impressed by these units' low EMC emission, and ground loop high frequency currents. Thanks, Anders, for tipping me about them!
- Not suitable for iPad, only for laptop charging with the music system off: An iPad power may easily be connected. But our 12VDC (Volt DC), supplied in cigarette lighter car connectors - to 230VAC (Volt AC) inverter (*1) generated too much EMC noise for the aux connection (being a switched mode power supply). Having a reliable 230V AC source in the car is so nice, because we can use the standard chargers, and also use a laptop in the car - simultaneously. In the new car, one of the 12V connectors do have power also with the key out, so it's possible to charge at stops using that inverter.
- But I will be trying a 12V to 5V charger, the iPad needs 2A - of the type that sits directly in the cigarette lighter connector. However, I would doubt that this could be made non EMC (as serial regulated with full power loss), since 14W (Watt) heat is rather stiff to get rid of inside the connector (Max 12V - 5V = 7V times 2A is 14W). I'll keep you updated.
(*1) "150W Power Inverter" from a manufacturer called "am" (bought over the counter at Mamoz here in Trondheim). We have used it flawlessly in the car some years now. It's small and rugged, all metal and no fan, with 90% efficiency (so it would need to cool 15W, relate that to the cigarette power supply). It replaced a plastic unit with a fan from another manufacturer that lasted one trip before parts of it melted. But Mamoz took it back.
The prototype


I have erased the car maker logo in the middle of the steering wheel in the above picture.

You need some aluminum, a good metal saw, two bicycle spokes, a rubber band, screws, solid plastic (I used som lexan), tape, a carabiner of some sort, cable ties and a spare few hours. I found all of this in a spare box in my shop. (Please help me with correct English words in this blog, my vocabularly falls short in this field.)

The iPad's glass is somewhat protected by its aluminum edge. But the pressure on the glass should of course be as small as possible. Using lexan plastic on the top, and a piece of tape inside, will fare well with the glass and avoid stripes which easily could have the glass fracture.

I will not do a do-it-yourself DIY recipe here. You'll make it, and hopefully you will laugh last.

The strecth in the rubber band is about 2 mm. Pull the holder 2 mm apart and slide it down from the top, or pull it at more strength and place it anywhere. This should be enough pressure, I believe. With that pressure, it's even possible to hang it up like a picture frame. Don't do that, ever.

At first I thought it best to curve the inside of the two aluminum hands, to follow the iPad 2's curvature. With the present solution, however, there's space for iPad 2 switches, camera lens ring etc. And also space for the flat end of the bicycle spokes, seen in the right part of the picture above.

The pressure to the sides is also relieved a good deal by the end of the aluminum hand which is pressed to the back side of the iPad. This probably also tightens the grip better, so that a shock will hold it better in place.


Be sure not to set the iPad on anything metallic, to avoid glass fracture when the car bumps up and down. If it's placed by the lock mechanism in the door, check that all parts there are plastic. I glued a piece of rubber inside each of the plastic bottom clips, as I believe that must be better than hard plastic. Also, should it kick up, have a look at the scenario and see what happens if the iPad's aluminum edge hits the top lock ring, which probably is metal. If Apple had designed for this, the less than one mm aluminum frame protecting the glass edge might have been made thicker. However, you might need a piece of rubber or perhaps leather up there? I found a plastic tube that seems to do the job (above). It slips easily on and off, and the lock holds it in place.

Also, find a good elastic rubber, the cheaper the less useful. I tested some in the garage, and found only one that I thought acceptable. It should not feel like chewing gum.

Post script: bringing it abroad

The other week we went to France and again rented the same car model, the one that we have at home. I packed the iPad 2 holder, the charger and the 3.5 mm sound cable. I did not succeed in connecting the iPad sound via Bluetooth, and there was no 3.5 mm aux input like at home, so we had to listen to the Navigon navigation lady from the box. This was better than one should think, and the iPad 2 only needed to be switched so much up.

The nice thing was that the holder worked like a dream. Also on the row of small bumps just before pedestrian crossings, even if I forgot to bring the plastic shield for the lock. We kept the iPad 2 in the upper position always. It did the little dance it should.

I started by stating that it's best with two persons in the car. It still is, but I heard that some built-in car navigation systems inhibit you to do quite a lot while driving. One may have to stop to set a new goal, I was told. Then, the difference becomes less.

By the way, the Navigon / iPad 2 pair in many ways outperformed the built-in system. Of course, except the integrated features which piped the most important info to the dash board's front display (like direction and road number). And the integration with the rest of the multimedia functions.

Search words in Norwegian: prototyp stativ holder for iPad 2 for bruk i hanskerommet på bil, som du kan lage sjøl selv, som ikke skal betjenes brukes av sjåfør i fart, bare passasjer, kan ødelegge iPad. Blåtann.
.

No comments:

Post a Comment