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With the Little Foot Elegance Photo I introduce my latest and likely last self construction project for a stepper motor controller device. The likely last one because the hardware offers almost everything that you like and the software leaves enough space to introduce new functions for years. For this there is no need to make any changes of the hardware and the update of the software can be easily done at your home PC.
Before I start with the self construction instructions I would like to give a short introduction of the new Little Foot Elegance Photo Steppercontroller.
I developed the Little Foot Elegance Photo because the Pro update for the Little Foot Elegance caused to many problems and I did not want to give up such a project. The LF Elegance Photo is no update it is a completely new controller device. As anything had to be done from scratch I had the idea of a project without any compromises. Though having the cost in mind I wanted to establish a hardware to fit all future needs, so a real future investment. :-D
And here we are, a stepper motor controller like no other has been created ever before. I do not know anything alike, leave alone the price! There is another do it yourself project but unfortunately the designer looses himself in expensive special parts you cannot purchase anywhere. This leads more and more to a project that had been introduced but you can’t do it yourself, what a pity!
Besides the countless features of the Little Foot Elegance Photo one apect was of special importance for me. The controler should be much easier to assemble, avoiding a wire mess, and keeping the price low. Another important point was to avoid special parts you can’t purchase anywhere. What is the use of a controler project you cannot realise yourself because you cannot lay hand on the parts needed? All the assembly parts can be bought, even from private persons, at local electronic stores, I layed less emphasis on „clicky colors“ but on the design of an economic and performant system. I think the features of the Little Foot Elegance Photo give you a clear idea. :-)
Some features of the LFE Photo:
Yes, I could go on for a few pages, but sure you want to try all that yourself. So let’s proceed to the do it yourself instruction. ;-)
Stop! The following paragraph must not be missed:
Vending or distributing my project for comercial purpose without my written permission is forbidden!
Before you start to build one you have to purchase the assembly parts. Costs will be about 300 Euro and in Germany you can get everything you need at Reichelt and/or Conrad. Your local electronic store should have all parts as well. In the Forum for Astronomy und Astroelectronic I published a list of links containing all information needed. If you have any doubts just ask over there. I do not answer questions via e-mail and just ignore such requests. You will find enough space on the forum for all questions that might arise. To get access to the LFE Photo forum you need a registration. This do it yourself instruction does not contain any schematic or list of needed assembly parts. Such care is taken because in the past thiefs stole my projects and published them as their own ones elsewhere. I know that there is no real safety but at least theft of a project is a little more difficult that way. ;-)
After you have purchased all parts, assorted the modules and heated the soldering iron you can start right away. The given sequence is just an example. Any one can do as he likes, but it is no fault to follow the sequence you find over here. :-D
As a first step we construct the heating of the display. To do this we cut the heater wire to a length of about 30cm and thread it into the holes of the table. It is easy to recognise the beginning and the end by the throughruninng contacts standing alone. The long rows are for the side having a layer of copper. This layer shall increase the efficency of the display heating somewhat and shows which side is the top.
This done we turn the table upside down. We cut off the ends of the wire leaving about 1cm, DO NOT CUT IT OFF ALL THE WAY. Now we solder the heater wire to all the troughrunning contacts from underneath. To protect the display and hold the wire in place we put some tape (Tesa for example) on the top side.
Now we turn our attention to the table of the hand control box. I recommend to stick to the display heating, so nothing can happen to it afterwards. The first step is to insert the temperature sensor through the table from underneath, adapt it to the size of the hole and mold it from THE TOP.
Now we put the heater table on top of the hand contol box table that way that the holes fit and the heater tables snaps into place. We turn the whole thing upside down and solder the two tables from UNDERNEATH. The throughrunning contacts are made in a way that they connect when soldering tin flows into the holes, bomb-proof! ;-)
Before we take the next step we check the total resistance and the contact of the two tables. This is easiest done from the bottom side just soldered. The total resistance should be about 27 Ohm.
Having succeeded the assembly parts are soldered onto the hand control box table. We start at the smallest ones and carefully proceed to the biggest . Take special care with the SMD parts!
As a last step the display itself, lying directly on top of the heater table, is soldered onto the HB table.
Having done this too we work on the hand control box itself. As the procedure is the same as for the little LFE I see no need for a repetition and ask you to read the information over. ;-)
Having completed the work on the box we attach the push bottons and switches and solder the wire tips for wiring later on. The wiring for the HB cable and the reading lamp is also done now, later it is not that easy any more. Here too the procedure is much the same as for the little LFE which should be taken as reference. ;-)
Having completed this work we put the HB table into the box and wire all push bottons an the two switches.
After this is done the HB can be closed and the HB plug can be soldered to the other end of the HB cable. You find the wiring diagram for the HB plug in the document Pins & Pads. The construction of the HB is now finished.
Building the central unit yourself takes somewhat more time. The procedure is much the same as for the hand control box. Proceed from the smaller to the big assembly parts. Solder the plugs and the screw terminal to it at the very end!
Watch out!!! Make sure NOT to solder the voltage regulators (IC16, IC17, IC18) on top like shown in the component mounting diagram, but mirror reverse from underneath. Unfortunately I do not know how to show this by graphics, but cooling the regulator shall be done by the box. The standing voltage regulators are mounted from underneath and then switched over towards the edge of the table.
Make sure that the voltage regulators are in good contact with the boxes bottom as you slip the table into the box!
Having done this the connection wires are cut to length and prepared for wiring. Then the wires can be soldered to the plugs and switches and to the plug and socket connector on the other side. In case of doubt FIRST READ, THEN ASK, THEN SOLDER!!!
If you succeeded you can start to put the parts together. To do this remove all the spacer pins of the Sub-D plug and socket connector on the contoler’s rear side. Then the rear panel is fixed by screws and wired.
Before we finaly can put the parts together the motor current needs adjustment. As a control cannot work without Firmware you have to install a Firmware first. The instruction manual of the Little Foot Elegance Photo tells you how to do so in detail. In case of doubt once again first read, then ask, then act! After the Firmware has been installed tune the motor current in RA and DEC to the maximal possible value. Depending on the setting of the adjustment potentiometers (R54 and R55) this value can differ a lot. Do not be afraid to tune to max on the display. Then use the potentiometers of the pads 11 (RA) and 12 (DEC) to set a voltage of 0.71V. Adjustment is now done and you can go on to put the parts together.
The table is slipped into the box from the rear , the front plug and socket connectors are put on from the front side and the box is closed by the front panel. Finaly all spacer pins of the SUB-D connectors are fixed. Congratulation, you have succeeded to build the may be most advanced telescope control world wide yourself!
Before you start to use the control you have to adjust the motor current so it fits your motors. You must read the users manual too!
CS and enjoy your latest award a Lot!
Copyright © 2009 by Anand Rajiva , E-Mail: LittleFoot@rajiva.de
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