Looking for a way to mount the dioder LED strips of Ikea inside my Ultimaker Original, I came across the design of Martijndewinter. When printed, I noticed that the small notches of the clamps where not properly designed for some of the 4 clamps, actually they where not attached to the main part. Next to that, I was not very satisfied with the way I had to mount the LED strips on the Ultimaker.
So, based on Martijn's design, I created 2 new clamps. One to mount the dioder strip on the left and right top side (this is different from other designs I found on Thingiverse), and one to mount the strip inside the left and right corner of the front panel (which is an improved version of Martijn's design).
There is one drawback: the top lights are partly shaded by the belt. However, due to the different angles of the 4 led strips, you will still have plenty of light on the print in progress.

The top strips will just fit in, you have to fumble the connecting cable a bit to let it run free of the axes. The side strips are easier, as there is more space for the strips.

The connection cables which are supplied with the dioder strips are too short for this construction, so you have to desolder the plugs and put some slightly longer cables to the plugs (about 50% longer should be sufficient). The cable is difficult to get out, you have to flip the notch in the plug up.

So, the top and front strips are interconnected at both sides. The power cables can be lead to the existing holes in the bottom plate. The white dioder has a connection box to connect up to 4 strips. The main power lead is guided along the main board. The power switch of the dioder set is not mounted to the Ultimaker, but you can do that if you want to.

The top clamps are attached using 10mm bolts. The holes are 80mm from the back and the front of the top panel, and 7mm from the inside edge.

The side clamps are attached using 10mm bolts. The holes are drilled 80mm from the top, and 120mm from the bottom of the front panel, and 22mm from the side panel (use the inside edge to measure from, measuring from the curved side is very difficult :-) )

When drilling, make sure you have a piece of plywood below the hole to be drilled (just a small leftover of the panels will do fine). Not only will it prevent splintering, but it will also avoid drilling through the belt.....

If you want to, you can use the dioder connectors to connect to the Utlimaker Original+ main board, Ikea has (luckily) used the same plug for this on the white version of the main board. It will take some soldering and you have to connect each set of the strips in a serial way, as the Original+ supplies 24V and the dioder strips are 12V. Next to that you have to create custom firmware to be able to switch on the lights. See https://ultimaker.com/en/community/8807-main-links-for-marlin-firmware for more information on this.
The Ultimaker Original (so not the +) is supplying 12v, but I have no proper knowledge on connecting led strips to that main board.

You will also need:
4 10x3mm bolts (top left and right)
4 14x3mm bolts (front left and right)
8 hex nuts
3mm drill