Ultimaker and Prusa MK2 heated bed mod

Ultimaker Prusa MK2 Heated bed solution

image of heated bed
After battling through the Ultimaker wiki and the reprap wiki to figure out how to get a heated bed working ont he Ultimaker, I decided to write up my solution.
The Documentation and information available the moment is pretty sketchy. After trying a couple of things and blowing up half my Ultimaker, I decided the wiki was a terrible resource, lacking in opertinent information at best, and leaving massive assumptions.
The biggest assumption on the ultimaker wiki is that you can connect the headed bed to the onboard FET driver directly. While this worked for me temporarily, the heat from the FET caused it to stop working. My advice is to NOT connect directly via the onboard FET and use a relay.

The instructions below are for how to connect a Prusa MK2 heated bed to the Ultimaker with board revision 1.5.6.

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3 Hour Hacks: Part 1


I am planning a small series of 3 hour hacks. Each hack will be allocated a 3 hour window only. There are penalties for failing to adhere to the rules. Points will start at 100 and count down. Rules are as follows:

  1. Research is time free. It does not count towards the total time. (learning should be free, right :) )
  2. Must not go outside of 3 hours. -10 points for every 30 mins outside of this.
  3. Must use all items available. Must not purchase any items for hack. -20 points for each item purchased. (Sub-note: You are allowed to purchase the first item, the one to be hacked only)
  4. Hack must be funny, witty, clever, convoluted, impractical, or otherwise absurd.
  5. The device must serve a purpose. It must have a use. -20 for no valid use!
  6. The hack doesn't have to be nice or finished. -1 point for each stupid build mistake.
  7. Upper limit of £20 for all parts in hack, even if from junkbox. Does not include initial purchase. Estimate prices, but be conservative :). -5 points per £/$ over this.

Hack 1) Hard Drive CPU/RAM meter.

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Android on Kaiser hacking

I have been messing around with getting Linux to boot on the HTC Kaiser, with the end goal of ditching windows. Presented is the LED hack. I am suffering from NIH syndrome on this one, but still cool.

EDIT: I got some emails asking how I got Android on there...
XDA-developers tells you what you need to know. Other non-Kaiser HTC devices should check the XDA developers Wiki

EDIT2: The phone works in Kaiser! Nice work premy!


In a nutshell-> An LED on the phone keyboard is flashed on and off at high speed by incoming serial data.
The serial code that is normally used to talk to a hardware UART is horribly hacked to pipe all serial communications out through the fn led on the keyboard. This is then read by an LDR that is connected to an AVR ADC port. The ADC port then polls the LDR waiting for it to go over a defined threshold. For each 8 bits of on-off flash sequences form the phone, the AVR will combine and put them into a register ready for reading.
The PC then reads the data through USB from the AVR using Dick Streefland's usbtiny software USB stack.

In fact, the whole hardware is based on my OSIF board, with a couple of extra headers soldered on and some small code to parse for the flash sequence.

Because it's coooool.
In all seriousness I needed to get that data out of the device somehow. Copying log entries by hand is a pain.

Where are the pictures?
Okay, Okay.

Yes, this is running Google Android :)

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VW Passat Comfort Control Module harness repair

If you own a VW Passat, and also have some funky things happening with your electronics you probably have something wrong with your Comfort Control Module (CCM), or at the very least, the wiring harness.

If your Passat has these symptoms, in part or in full, you are almost certainly in for a rough time.

  • Remote keyfob not working
  • No electric windows
  • No interior lights
  • Funky clicking noises coming from the passenger seat (RHD)
  • General strange things going on with your electrics

All of these things are controlled by a box called the Comfort Control Module (CCM) that sits in a box under the passenger floor panel (RHD). This box hold all of the key electronics that control all of the above functions. Unfortunately for us Passat drivers, there is a bloody awful problem with water getting into the foot well of that car, and ruining your fancy control electronics.

If you have, or suspect you have water coming into the car, I would highly recommend you follow this excellent guide to cleaning out the drainage holes by Ewan

After you have followed this guide, and you have removed the source of the problem, you will need to check all of your wiring, and also your CCM.

So how do you do it? I will try and give you a head start. I wasn't really prepared for what would be involved in this, and took some photos as a reminder to me... I always forget where all of those screws go.

As it turns out it wasn't too painful.

Things you will need

  • A philips head screwdriver
  • A flat head screwdriver
  • A soldering iron/cable joining kit
  • (Optional) A multimeter
  • (Optional) A VAG-COM KKL cable and a registered VAG-COM software
  • patience
  • A strong arm and a indifference to blood, sweat and tears
  • Caffeine. Tea/coffee. Whatever is your poison

EDIT:- I removed the clip connections and soldered them while trying to figure out a different issue. It is much cleaner and I have more faith in this arrangement

Step 1 - removing the panels

The CCM is under the carpet in the passenger foot well. You need to remove a couple of pieces of trim to gain access to this.

The first thing to remove is the plastic trimming at the front of the door.

First up is the panel on the left of the foot well, in front of the door. This is held in with one screw and covered by a plastic cap. Use a small blade to pop the cap off, and then remove the screw.
This panel also has some clips onto the chassis, so more brute force is needed.
This foot plate is clipped into the chassis, and comes off with a reasonable amount of force. Use a flat headed screwdriver to gently prize it up from the front of the car backwards. I started from the underside of the panel (the floor) and pushed upwards with the screw driver.
This piece of trim runs the whole length of the car, but you should only need to unclip it as far as the seatbelt.
Last in this section is the clip that hold the carpet to the floor. Although there are 2 of these, I found I only needed to remove the one closest to the door.

Step 2 - lift the carpet

The carpet is very thick, and will require a lot of force to lift it up. You will not be able to lift it all the way over to get easy access, as the whole carpet is in one huge piece. Believe me, you don't want to remove the dash to get it up... it is not worth it.
As you can see from mine, there is rather a lot of water in there. Get a cloth and mop it up. I also ran a fan heater in the car for a few hours to get the wetness out of the carpet. This makes it easier to get though the next bit without getting wet.

Step 3 - remove the CCM

You should see a large black box with a bundle of wires going into it. Put your hand in, and pull the black box out. It is not attached to anything, so it comes out easily enough.
The module is inside of this plastic box. As you can see from the photo, the box has clips on one end. Use your flat headed screwdriver to pop these open. Inside you will see the module. The wires go into two large connectors that are plugged into the CCM.
Remove the CCM from the enclosure by flexing the plastic clips away from the base of the module. be careful not to snap them off. Be gentle.
There are push clips at the top and bottom of the connector. Push these and remove the connectors. Slide the rubber seal upwards to remove the harness from the enclosure.
You should now have the harness and box separated.

Step 4 - Clean and dry the CCM

You will need to check the CCM printed circuit board (PCB) for water damage. Removal is similar to the larger enclosure. Use the flat screwdriver to pop open the clips. There are 2 at each end.
Now you should have your CCM PCB out. Be careful not to touch the sensitive electronics, as this may cause it to never work again.
Look over it for water damage. If your board look really corroded, you may be out of luck. You can replace this with a second user one, but this is beyond the scope of this guide. If you need another one, you will need to get some additional help form the vw forums. You will need a VAG-COM cable, and a license to program your new module. Luckily mine was clean.
Put it somewhere nice and warm for a couple of hours.

Step 5 - Look over your wiring harness

As you can see, my wiring harness was a goner. The water had soaked into the binding, and it had come off in huge sections.
You will see some wires are wrapped in a black tape. This is where they are factory joined to the main harness. This is where they fail. Carefully remove the wrapping from the cable from the twin connectors backwards.

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How to Build an Open Source MIDI Keyboard

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GPS Hack

Pretec compactGPS serial modification

Below is a description of how to modify the compactGPS
to work with a standard serial port.
This mod will allow you to use the device using your PDA
serial port, a PC serial port, and a PDA/GPS car kit.

This device is a compact flash adapter for GPS If you are a walker or hiker, you should look at this device. It is very accurate, and has a very low data acquisition time.

This worked fantastically for me for 2 years, until I discovered TomTom. I purchased tomtom and installed it. This also worked fantastically. I could plug in the receiver, and get a location of my car!
The only problem I had was that I didn't have enough memory in the PDA to accomodate large maps. I was stuck with very small maps. The problem is that the GPS receiver uses the Compact flash port... The same port I need for a memory card upgrade
This became very annoying, and I went to work...

First I disassembled the GPS device (it was out of warranty) What I saw inside was a small device, and 5 wires connecting it to a compact flash card.

My first thought... only five wires? I could put an extension on that, make the GPS part separate. This would at least solve the problem of having to hold the PDA at silly angles the whole time. It could be placed anywhere... on the dash, or atop a rucksack.
So I went to it. This also worked fine. But still the problem of the small maps.
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Extending the GPS cable

Different view of gps wiring

Building the module

More wiring

Still waiting for the glue to dry

Drying glue

Drying glue

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