I'm going to be brief about making this thing because you will have to do some problem solving to build this based on the tools and materials you have access to. For the most part, its not too difficult and the tools are fairly common. Some thinking may be required on your part.

The timer was removed from its plastic housing, and I found it had a convenient 1/4" shaft on it, which was easy to mount a gear on. The knob was kept to allow me to wind up the timer easily.

The gears are laser cut from acrylic, as is the top of the tracker. If you don't have access to a laser cutter or don't want to spend the money to have it cut by a laser cutting service, there are other Instructables on how to make wooden gears from plywood using a saw. You can definitely recreate these gears using this method. The gears were designed from the Solidworks Toolbox and altered slightly for my use.

The gears are held on shafts which have a flat side, and a point at one end used as a simple pin bearing. The idea is to minimize friction by having a very small surface area where the weight is. This proved to be insufficient for the large gear, so a spring and a bearing were added beneath it to hold it in place firmly, while still minimizing friction. The top of each gear shaft is held in a small nylon bushing which is machined to press into the acrylic top, keeping it in place.

The wooden portion of the housing is just two pieces of 1.5" thick poplar board from the local hardware store. I bolted the two pieces together while working on them, then glued it afterwards, because hole saws can't cut through that thickness so I needed to be able to separate the two pieces during the cutting.

The bottom is 18 gauge steel plate, cut to match the rest and align with the four bolts that hold the whole thing together. On the very bottom is a 0.5" thick aluminum block machined with a 1/4-20 hole where the tripod mounts to.

The alignment laser is mounted inside a little threaded holder that goes onto the end of the shaft where the ball head normally mounts. I use this to align the RDS correctly, then remove it and install the ball head. A simple version of this would be to cut some extruded aluminum to make an X-block that the laser could be strapped right to the side of the ball head, if the ball head has a good concentric face on it. Mine does so I will be using this method in the future to align, as it is easier and probably more accurate.