User avatar
RichardUK
Posts: 241
Joined: Fri Jun 01, 2012 5:12 pm

Pi into Old Laptop

Sat Feb 14, 2015 11:34 am

I've started a new project after finishing my 3D Printer project.
I brought an old 15inch laptop from eBay for £5 + £9 postage, there are a lot on there. I've gutted the case as you see in the pictures at the bottom of this post. I have ordered a LVDS board made to drive the panel I have from the HDMI port on the RPi. So now I am looking at the battery system. And this is why I am here, the charger and battery that came with the laptop work fine and will give a nice fit, was made for the laptop after all. But Li-ION don't seem that safe for a maker project and it's hard to find a charging circuit. I did find one here but it's full of warnings.

I need 5v for the Pi and 12v for the LCD driver. I maybe able to get 5v from the LVDS board.

So, to my question. What are my options?

Here are the pictures after the laptop case has been gutted. I'm using a B+ for fitting but will use a Raspberry Pi2. May have to trim the USB ports. A bit tall. At the moment I'm £34 down but still need to get the Raspberry Pi, sort the battery, keyboard and look at the touch pad. Hoping to be in under £100.

Many thanks. Richard e Collins. :)

Image

Image

retard
Posts: 4
Joined: Sat Feb 14, 2015 1:28 pm

Re: Pi into Old Laptop

Sat Feb 14, 2015 7:47 pm

How much power will your "laptop" consume?

And how much run time are you expecting/shooting for?

I'd run a Lithium Polymer battery with the appropriate capacity or run a few of them together to bump up the run time or voltage as per your requirements.

User avatar
RichardUK
Posts: 241
Joined: Fri Jun 01, 2012 5:12 pm

Re: Pi into Old Laptop

Sun Feb 15, 2015 10:09 am

The idea is to get a few hours on battery, I want to be able to have it uninterruptible so that plugging it in to the mains it still runs and charges the battery. I don't know how much it will use, I should be able to measure that with my bench supply when I have all the parts to mock up the design.

I did a little more googling about and I'm thinking either 14.8v battery and a car pc power adaptor that will take the varying power out put and give me 12v and 5v that I need. Or go for 7.4v (or similar) and a power boost up to 12v. What ever happens I think I will need a voltage regulator to deal with the voltage change as the battery drains. I'm far from a battery expert, learning as I go. :)

edit: I've done a bit more research and it seems that the battery has the charging circuit built into it with an i2c interface for reading it's state. I done some probing and looked at the connector on the old laptop motherboard and seems four pins are the voltage @ 14.8v and two are the i2c pins with a 7th pin that seems to give out 14.8v but is connected differently, I think this needs to go to ground to enable the battery. This is based on what has been done for other batteries people have reversed engineered.


Many thanks,
Richard.

User avatar
RichardUK
Posts: 241
Joined: Fri Jun 01, 2012 5:12 pm

Re: Pi into Old Laptop

Sat Feb 21, 2015 11:50 am

So I got the driver board for the display. Works really well and should fit without problem. Now I can start to lay it out and have a think about connecting the keyboard and touch pad.

Here is the eBay listing for the board, £15 and took 10 days from china. So very pleased with that. Runs @ 1440x900 :)

Image

Severian
Posts: 49
Joined: Wed Jul 10, 2013 6:22 am

Re: Pi into Old Laptop

Mon Feb 23, 2015 6:29 am

Howdy,
I have been wanting to do something similar to this. The biggest thing I have not figured out is using these HDMI to LVDS boards. They all say to send them your exact LCD pannel model and then they will tell you if their board is compatible. Did you just get lucky, or did youfind a compatibility list somewhere? Or, maybe something else. Your idea of building into al old laptop is interesting, but I plan to make a custom box for mine. I expect it to look something like a lunchbox.
Thanks,
Ralph

Picer
Posts: 3
Joined: Fri Jan 30, 2015 6:25 pm

Re: Pi into Old Laptop

Mon Feb 23, 2015 3:55 pm

Hi,

I did something similar with an broken Acer laptop. So I can give you some hints.
RichardUK wrote: So, to my question. What are my options?
Power supply
I had the same issues with the battery charging and in the end it was to complicated for me. I used an dual voltage power supply I had laying around. So not really portable, but it works for me. If you come to a simple solution, I would be interested.

Keyboard and Touchpad
The touchpad has probably an PS/2 connection. You will need an PS/2-to-USB adapter. The cable is probably an CSI/DSI ribbon cable with around 12 pins. I did not use the ribbon cable but soldered directly to the touchpads board. This was an Synaptics TM540. There are some how-to's for an TM1004 chip in the net. These worked fairly well. Only the left and right mouse buttons were on other pins.
The keyboard has probably only an CSI/DSI ribbon cable with max. 26 pins. You will need an keyboard controller from an old keyboard. From an USB keyboard or from an AT- or PS/2-keyboard if you use an combined PS/2 keyboard and mouse adapter. More on the keyboard connection I wrote here:
http://www.raspberrypi.org/forums/viewt ... 40#p681340

Audio
I did not follow this road very far, but you can use the speakers with an amplifier. It did work with an amplifier I had here, but this one was to large. It should work with something like an PAM8403, but I did not test it.
I decided in the end for an USB soundcard.

USB connections
I put an activ 7 port USB hub in the case. One port is powering the Pi, two ports are for internal use (not used at this time) and 4 ports are going to the outside.

I used an Pi B+ and replaced it in the last days with an Pi2B. Of the four USB connections on the Pi are two free, one is for the combined PS/2 keyboard and mouse adapter and the last goes to the USB hub. For the last I soldered a new cable with only the data lines to prevent backpowering.

Good luck
Robert

User avatar
RichardUK
Posts: 241
Joined: Fri Jun 01, 2012 5:12 pm

Re: Pi into Old Laptop

Mon Mar 02, 2015 11:47 pm

Severian wrote:Howdy,
I have been wanting to do something similar to this. The biggest thing I have not figured out is using these HDMI to LVDS boards. They all say to send them your exact LCD pannel model and then they will tell you if their board is compatible. Did you just get lucky, or did youfind a compatibility list somewhere? Or, maybe something else. Your idea of building into al old laptop is interesting, but I plan to make a custom box for mine. I expect it to look something like a lunchbox.
Thanks,
Ralph
I think I got lucky, I took the panel out and used the part details on the back. When I searched eBay found a seller that had hardware for the panel I had. I still had to let them know which one it was as they selected the correct cable. I've spent the last few days lengthening the cable so that the control board can fit in the laptop case.

User avatar
RichardUK
Posts: 241
Joined: Fri Jun 01, 2012 5:12 pm

Re: Pi into Old Laptop

Mon Mar 02, 2015 11:54 pm

Picer wrote:Hi,

I did something similar with an broken Acer laptop. So I can give you some hints.

Good luck
Robert
Thanks for the feedback, that will help a lot when I come to get the keyboard and touch pad working. Have a few old USB keyboards knocking about to sacrifice. ;)

One idea for the battery I had is a car PC power DC-DC converter. Most only do 12v to 12v. But the £40+ (ouch) ones can go from 6v to 24v range and give out the 12v and 5v I need. I've given up on the battery pack that is for the laptop as it's too easy to make a very bad mistake hacking them about.

User avatar
RichardUK
Posts: 241
Joined: Fri Jun 01, 2012 5:12 pm

Re: Pi into Old Laptop

Tue Mar 03, 2015 12:02 am

So I have finished the work on the display, I've had to lengthen the cable, 24 wires to cut and solder. Used twisted wire from a network cable to match the original.

Image

Here is a youTubevideo too. :)

Picer
Posts: 3
Joined: Fri Jan 30, 2015 6:25 pm

Re: Pi into Old Laptop

Wed Mar 04, 2015 11:22 am

Just two pictures from the converted Acer laptop.

Image

The case shortly before reassembling. On the left side a board with USB- and AUX connectors. On the lower left corner is the power distribution board. Power comes from the connector on the upper left side, is routet to a switch at the right side and back to the board. From there 12 V go to the panel driver board (the green one one the right side) an 5 V to the USB-hub ( not installed yet).
In the middle is the keyboard connector. This is connected to the keyboard controller on the lower right side by the grey ribbon cable.
The red wires on there are part of the keyboard matrix adaptor. The keyboard controller is underneath. From there the keyboard cable goes back to the middle into the PS/2-USB adaptor. The second cable, the one with the green jack, comes from the touchpad.

Image

The case is closed. As there is a large cover on the downside, the Pi and the USB hub can be installed from here. This provides easy access to them. So replacing the Pi B+ by an Pi 2B was a matter of minutes.

Robert

User avatar
RichardUK
Posts: 241
Joined: Fri Jun 01, 2012 5:12 pm

Re: Pi into Old Laptop

Wed Mar 04, 2015 8:11 pm

You've got the same LVDS board as I have. I've done some work and got the LVDS board permanently mounted in a nice place at the back. I tried a control board from a few old USB keyboards but no luck. I do have a spare TrinketPro that I could turn into a keyboard scanner. I think it has enough pins. Can act as a USB device. Some goggling this evening to see what would be needed to get that working. :)
I have also order a better HDMI cable to help with routing.

This is the layout I'm going with, I've removed where the battery would go. Using the base of the battery container to fill the hole in. :) It will leave room so that I can have space with a riser for access for the IO pins. Maybe print a recess to make it neat.
But current job is the keyboard.

Thanks for the feedback everyone. :)

Image

cae2100
Posts: 143
Joined: Tue Jan 08, 2013 10:35 am
Contact: Website

Re: Pi into Old Laptop

Wed Mar 04, 2015 10:26 pm

Ive been looking into doing this also, but using the existing laptop battery so it didnt look too out of place having extra batteries or spots missing. This is what I found to help with that:
http://linuxehacking.blogspot.com/2014/ ... aptop.html
They look like it just has an enable pin on some laptops, but others, they're on all the time, other than that, you can read the charge, statistics, etc from the battery itself through SMBus, which is pretty much the same thing as I2C, so you should just be able to directly read everything through that.

For the touchpad, Ive discovered that alot of the synaptic touchpads are just old ps/2 touchpads, which a simple microcontroller can do the ps/2 to usb simply, or just get a cheapy little converter to do it off of ebay.
If it isnt smoking and blown into pieces, it's not pushed far enough yet. :P
http://cae2100.wordpress.com

Return to “Other projects”