You don't know til you try . . .

Cisco SG500 <-> 2960/2950 VPN

, posted: 20-Oct-2015 09:47


I am no Cisco tech so this may seem obvious to the Pros.
Googling did not return the solution in one hit.
Recently had to get get a network of Catalyst 2960 and SG500 to work together with VPNs.
The SG500 was the backbone and powered the 2960's via POE.

The SG500's do not support VTP.
They do support the industry equivilant of GVRP (IEEE 802.1p).
This means you have to manually set up VPNs on both devices.
Names assigned to the VPN do not matter only the VPN number.

The ports default to Trunks, you would assume that all VPN traffic would pass through by default.
Not so.
1. Create the VPN on the SG500.
2. Assign the port to the VPN.
3. Add the port to the VPN.

2 and 3 may seem like the same thing.
2 Controls access, while 3 controls membership.

Of course I may be doing this wrong but this is what I had to do to get it to work for me.

You can imagine 10 switches x 5 VPNs adds up to a lot of manual configuration without the auto propagating VTP.

Good setup guide on the SG500

VLAN and VTP config information


, posted: 9-May-2015 10:24

I have been helping a friend out with an extended warranty claim at dicksmith.

They have basically mucked her around and trying to fob her off.

Maybe a little social media pressure will make them do the right thing. :)

Her story

My post on their FB page.

Hopefully I can post an update in a few days when #DickDelivers ;)

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Debugging, old school

, posted: 25-Jul-2014 16:25

This user complained of intermittent crashes and failure to boot.
Externally it looked ok.
Not too much dust.

After opening noticed little black streaks all over the place.
Identified as cockrock feces.

Sure enough I spotted some live ones chilling out on the ram.

I wonder how manymore I will find toasted in the power supply.

 photo db-1-20140724_091040_zps57bd3a3e.jpg  photo db-2-20140724_091112_zps1b27b88b.jpg

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Mobility Scooter eCarts conversion

, posted: 30-Jun-2014 19:58

After seeing how cheap mobility scooters were going for I decided to try and turn one into a little electric cart for the 'kids'.
Mechanically they would be worlds better than the plastic kids ride on toys you can get.


I wanted a 4 wheel model, 3 just wasn't going to cut it.

Picked up one for $100 ish.

Cosmetically it was a little rough.
Frame OK.
Batteries were dead.
Controller had a fault.
Motor OK.
Tyres OK.

The important bits were ok.
Frame, Motor, Tyres.

Due to the age of the system, there was not many troubleshooting documents to be found on the interweb.

I also wanted to run it at 36V, which the stock controller would not be happy with.
Going diy you do loose some of the nice built in features of the controller, unless you buy another with those features.
-Over current protection.
-Regenerative braking.
-Speed regulation
-lots of others
Something with these features is about us$230 landed

The controller was stripped down to see what was inside.

12 years old? Look's like new :)

H-Bridge Mosfets were rated to 60V. P60NE0
There were 2 Driver ICs. ir2104
We will be able to reuse this part of the controller.

The drivers make it much safer on the hobbyist since you can't short the battery by setting the wrong Mosfets on.

There was a voltage regulator onboard (7805) but I could not easily figure out how to turn it on.
And didn't want to risk breaking anything else on the board in case I want to use it later on.

Cut the signal traces to the H-Bridge drivers.
Supply control signals and whola.
Working motor controller.

Bits used
-12v Regulator
LM317, might bump it up to 15v.
Or change for a DC-DC to maximise efficiency.
-Arduino ProMini v2 (Clone, m168)
-Pedals from a computer steering wheel racing set.
-Battery will be a Lithium Polymer (LiPo) pack from Hobbyking.
us$116 landed for a 33.3v(9s) 5.8Ah
Top speed should be 15-20kp/h
At low speed for the kids we should get 30-45 mins runtime.

Currently the program on the Arduino is pretty simple.
Push accelerator pedal to go.
Let go to coast.
Push brake to stop.

To potentially add
Pretty simple in code.
Just need to add a switch.
-Boost button.
Low speed with a 10 second full speed boost available every few minutes.
Make racing interesting.
-Adjustable max speed.
So multiple carts can be set to the same max speed.
During a race it will be driver skill that determines the winner.

Other people have put petrol motors in theirs.
I stayed with electric to keep the noise/maintenance/risk down.
A friend is helping with the metalwork/fabrication side.

Can do a more detailed write up if 3+ GZ members are interested. :)

Android Stealth Instant media upload

, posted: 18-Mar-2013 19:08

So you are an activist or high risk photo journalist.
Or just just filming the fuz doing something they shouldn't be doing.

You are documenting evidence when someone grabs your smartphone or demands you delete the incriminating evidence.

While I am not any of the above the technical aspect interested me.
What is the quickest way to get media off your device with the fewest

Many camera programs come with a share feature.
The new google+ client also has instant upload.
Unfortunately it uploads any photos/videos you take.

What if you do not want all you your snaps uploaded?
What if you need more?
Or in this case less.

No notification that your local media has been synced so who ever has
your device has no idea that the images are already in cyberspace.

I tried a few apps but all failed on one point or another.
.Too many clicks
.Unable to be selective about what is uploaded
. Notification of upload

1. You need a camera app with a custom store location that is different from your main app.
2. Dropbox account + Dropsync

The wining combination for me.
1. Mobile Hidden Camera - zecurizoft
Even has a disguised icon/name and stealth mode so there is no indication the device is recording.
Set the video to auto segment at 5mb , makes background uploading easier.
The downside is there is no viewfinder/preview so you do not see what is capturing.

2. Dropsync - TTXAPPS
Can be set to stealth sync in the background with no notifications.
Configure it to sync only the alternative camera apps store location.

-In use-
Unlock phone.
Start app.
Start record.
Point in direction of action.

-Vs normal-
Unlock phone
Start app
Start video
Point in direction of action.
Stop video
Select share
Select share method, (facebook, etc)
Wait for upload.
Start next video

Hope you are in a good reception area.
If you get caught and told to show them the images, start up your gallery app.
Nothing there as the files are stored in a non indexed location.
If your device is taken from you it will keep uploading until power is removed.

Someone non technical will have a hard time knowing what to look for.
Unfortunately the giveaway is the network icon showing data transfer.
That might no be a bad thing as it also let you know it is working.

So be prepared before you go looking for trouble
Try me

SATA SSD into an IDE only laptop.

, posted: 2-Feb-2013 19:07

Why you ask?
17", 1920x1200 resolution
This will be hacked into an industrial application so the fewer moving
parts the better.

We start with a Dell Inspirion 9300.

The current going rate on trademe is nz$150-200.
Pretty good for a 17" 1920x1200 display.
Not the fastest processor but enough for my application. PentiumM

Depending on what you are doing you could use a SD/CF to 44pin ide adaptor.
A lot less effort but you are limited to slow performance.
You can still buy IDE SSD's but they suffer from first generation controller issues.
Intermittent freezing, poor speed.

-Options left were
1. SATA to USB adaptor
2. 44pin IDE to Sata adaptor
3. IDE CDRom to SATA tray.

While the seek times would still be great the transfers would max out at usb2, 30 Mbytes /s

It won't fit in the original HDD drive bay.
Not a major as in this case the PCMCIA is on top of the bay.
Removing this makes enough room to keep it all in there.
Unfortunately the adaptor does not work 100%.
It boots and then the drive disappears.
Not sure if it is a os thing.

Photobucket Photobucket

Fit wasn't great so had to strip it down to bare bones.
The bios would not boot off the drive directly as it was not detected as an optical drive.

A. You can modify the boot loader on the primary drive to boot from the second drive.
Not the best as we are trying to eliminate that drive.

B. Boot from USB and point to the second drive.
Now you have a usb sticking out of the machine.

C. Could not boot from SD reader, no bios option.

This BIOS complains hard when there is no primary HDD.
Stalls boot for 60 seconds before giving a continue message.
So I will get a SD to 44pin IDE adaptor to shut it up and keep things tidy internally.

Until that arrives I will modify the USB Stick into a more streamline configuration.

We are limited to IDE/ATA100 speed, 90Mbyte/s actual ?

Further modifications on this machine might involve putting on bigger heatsinks for complete silent operation.

To make the USB boot stick I used

Samsung galaxy cutdown

, posted: 3-Jan-2013 22:07

Further to my last entry about broken screen.

What is the bare minimum required for it to operate as a wifi network camera?

This much.

Photobucket Photobucket

Well actually a little less.
But I kept the speaker, sim/sd socket on there.
The lower half had the hard buttons, mobile antennas, vibration motor, mic.

Android remote control via USB

, posted: 13-Dec-2012 09:42

With broken screen still a useful device.

Was using it as a network camera.
IPWEBCAM, great program.

Samsung Galaxy S + 30m drop + asphelt =

Everything else still worked, just no screen.
The top part of the digitizer still worked.
Just enough to slide unlock.

Looked into options to remote control it.
All it needed to do was auto start the IPWEBCAM program.

There was the app based methods.
VNC, Team viewer.
Not much good here as it required them to be installed.

Came across Screencast.

Just what I needed.
Unfortunately I needed to run some commanded that required root access.
The phone was rooted, it still required the allow button to be clicked.
Easy if the device had a full D-Pad.
The Galaxy S does not.

Final part of the puzzle

And we have a winner :)

So if your screen is toast but you still want to poke around your device, here is how.

Also tried T-Plan robot.
Promises remote control without rooting.
Could not get it to work easily.
I didn't bother asking for support as I got screencast working.

How big a heatsink do you need to run a green laser pointer continuously?

, posted: 7-Jul-2012 09:53

At least this big. Ambient 15degrees Celsius.

Purchased from eBay, us$4.61 including shipping.

I need to run them 12 hours at a time, overnight for a project.
Due to the low price these do need a few seconds to warm up.
Once warm they behave as normal.
They start dimming when the case get to 28+ degrees.
Case is diameter 13.75mm. I only have a 13.5mm drill bit so a little pressing with the vice get's it in there.
I could also have scrapped off the rubber black coating for better heat transfer/fit.
Or used a smaller/no heatsink and fan.
Being battery powered why waste energy when you can go passive.
Will also be quieter.

While they many only seem like toys with 5mW of power they are still dangerous due to the concentrated nature of the beam.
Keep away from eyes and planes.

Laptop backlight woes

, posted: 4-Jul-2012 09:46

You know the story, turn the laptop on and screen is dark.
It makes all the right noises.
In order of least to most expensive fix.
Cables - Inverter - CCFL Tube - Screen - Mainboard

In my case I could still see a image with a torch shining on the screen.
It also flickered on briefly at boot.

YNV-18 , HP 8730W
I scoped the pins to make sure it wasn't the mainboard.
7 pin connector.
1+2 , Vcc, either battery or pluged in ac adaptor.
3+4 , Gnd
5,6,7 Didn't note exact allocation at the time,
PWM (for brightness control), Enable Backlight (active high), Enable Light sensor (active high)

The hunt for an inverter began.
A used replacement was located online.
us$14 including shipping.
Even with the fastest shipping it was 4+ days away so went with standard shipping 5-14 days.

On to Trademe for something temporary.
There were a few pin compatible units available.
Purchased one.
Tried a few when I went in to collect.
No go :(
Grabbed a known working one that wasn't pin compatible and tried my luck.

It was also 7 pin.
Wired the 3 control signals to the Enable backlight line.
It works :)
I didn't make the joining cables long enough, otherwise I could have put the cover back on.
No major, just wait for proper one to arive.
I can still close the lid.
Full brightness all the time though.

I also contemplated and upgrade to a LED backlight.
Nearly double the brightness would come in handy during summer outdoors.
Unfortunately they don't hav e a 17" kit.
No eta on one either.
I could have joined two 8.4" kits together.
May still do if I find this too dim outdoors.

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