Make It Move

Description

A good quality, temperature-controlled solder iron is probably the most important accessory for any serious electronics hobbyist.  However, in a pinch, other types of soldering tools can get the job done.  Just be careful not to over heat the PCB, as this can cause the traces to delaminate from the board.

The eutectic lead solder alloy 63/37 is easier to work with than 60/40 lead solder, as it melts at a slightly lower temperature.  However, 60/40 solder is fine as long as it's designed for electronic work.  Avoid using acid core solder, as these can damage the components and the PCB.

You'll need a pair of diagonal cutters to trim off excess wire leads after soldering components such as resistors and capacitors.  Amost any brand of cutter will work, even ones sold for use in making jewelry, as long is it's designed for cutting wire.

Masking tape can be used to temporarily hold slippery components in place while you solder them.  Masking tape, however, works better than scotch-type tape, as the paper backing on masking tape hold up better when subjected to soldering temperatures.

While not essential, we strongly recommend adding an inexpensive multimeter to your tool kit, as it can help you identify and verify resistor values (some models can even measure capacitors and inductors) and check voltages.

It often feels like you need extra hands when trying to hold a PCB board still while you solder in components and this contraption, which is available from many different vendors, can be a real frustration reducer.  And,a s shown, many models also include a magnifier, which can help you correctly identify resistor color code and also get a close up view while you solder tiny connections.

Breathing in fumes from molten solder is probably not the healthiest thing to do, so it helps to have a way to suck away the smoke and odors.  You can buy professional systems that have activated carbon filters, or you can do what one enterprising individual did and build your own fume extractor out of a fan salvaged from a defunct PC.  Click the image to the left for more details.

Instructions

Inspect the printed circuit board (PCB) for damage and to get familiar with the part designations printed on the top side of the board.  Also, before you beging sodlering, read through the instructions below and make sure your kit included all the parts need to assemble it (we appologize in advance of we screwed up and failed to include something) and that you can properly identify each part.

Note: if you're missing a component, please contact the email address shown on the assembly diagram included with the kit for a replacement part.

First, make sure none of the pins on the bottom of the DIP socket are straight.  If not, carefully straighten them.  Then press the socket into the 8 holes in the PCB where the ATTINY designation is displayed and check to make sure the socket lays flat on the PCB and that all the pins show on the other side.  Also, be sure to align the notch in the top of the socket with the same mark in the pattern printed on the top of the PCB.  This will help avoid putting the microcontroller in backwards in a later step.

Use a piece of masking tape to hold the socket to the PCB and prevent it from moving while you solder all 8 pins on the other side.  If desired, trim off the excess from each pin with diagonal cutters.

Press fit each both potentiometers into the positions marked P1 and P2 on the PCB.  The parts should snap into place but, if not, use a piece of masking tape to hold them in position while you solder all three pins on each potentiometer.  If desired, trim off the excess from each pin with diagonal cutters.

Press fit each both pushbuttons into the positions marked STEP and RESET on the PCB.  Note: the pins are in a rectangular pattern, not a square, so the buttons will only go in one of two ways.  The parts should snap into place but, if not, use a piece of masking tape to hold them in position while you solder all three pins on each pushbutton.  If desired, trim off the excess from each pin with diagonal cutters.

Depending on which kit you received, you may have two sets of 3 pin headers, one right angle set and one vertical set.  Which set you install depends on how you intend to use the Make It Move board.  The right angle set is good when you need a low profile for the board.  The vertical set makes for a more compact PCB assembly but, as the connectors to attached servos will then stick up vertically, the completed assembly will have a higher profile.  If in doubt, we recommend you attach the right angle set.  If you use the right angle set, the pins should stick out and point away from the PCB.  Use a piece of masking tape to hold each header in position while you solder it.  The pins on these are rather thick, so be careful if you try and trim them with diagonal cutters.

Install resistor R1 (color code Yellow, Violet, Brown), solder and trim leads.  For more information about resistor color codes, read this page, or check this handy guide.  If you have trouble reading the color code, or are unsure you have selected the right resistor, try using a magnifier, or check the value with a multimeter.

Install resistor R2 (color code Brown, Red, Red), solder and trim leads

Install resistors R3 and R4 (color code Green, Brown, Red), solder and trim leads

Install capacitor C1, solder and trim leads

Insert the LM317 voltage regulator being careful to align the flat side of the plastic package with the flat side of the symbol printed on the circuit board.  Note: the leads may already be bent onto the .1 inch spacing needed to fit into the hole pattern on the PCB, or you may have do bend them manually.  If you have to bend them manually, use needle nose pliers, work slowly and and be gentle.

Thread the leads of each wire coming from the battery box through the hole near the outside of the PCB down from the top, then loop back up through the adjacent hole directly above it (refer to the PCB image above.)  The red wire should connect to the + pad and the back wire should connect to the - pad.  Leave both loops of wire underneath the PCB slack while you solder the wires coming out the top of the + and - pads, then trim the soldered wires.  Finally, carefully pull the wires to remove the slack.

If you have a multimeter, we recommend that you test that the voltage regulator is working properly before you install the microcontroller chip.  Start by putting 4 AAA cells into the battery holder with the switch in the off position.  Then, move the battery switch to on and make sure that nothing on the board, or the wires from the battery box get hot, which might indicate a short circuit.  If anything seems suspicious move the switch to off immediately and carefully look for possible causes of shorts, such as solder bridges.  If everything seems OK, use the multimeter to check the voltage regulator by touching the positive probe lead of your multimeter (usually red) to the upper right contact on the DIP socket (see PCB photo above for a reference) and the negative probe lead (black) to the lower left pin of the DIP socket.  You should see a reading of approximately 4.5 volts.  If not, you may have installed an incorrect value for R1, or R2. 

Carefully inspect the ATTINY85 chip for bent leads and carefully straighten any that may be bent, or misaligned.  Note: the pins on both sides of a brand new chip tend to be spread wider at the points (like this / \) than the width of the socket, so you may need to gently bend them in so that they're parallel (| |) and can fit into the socket.  Also, it's very important that you install the ATTINY85 with its pin 1 (the pin with the small hole, or dot next to it, as shown in the photo at the left) so that it's closest to the notch in the socket (and also the notch in the printed symbol if you installed the socket correctly.  It can be tricky to get the chip to go in the socket smoothly, so take you time and make sure that none of the pins bend out, or under the chip as you insert it.  This type of socket is designed to hold the chip in securely, so it can take a bit of force to get the chip seated fully into the socket.

Here's what you should wind up with when you've completed all the steps described above.  Good job!  However, before you move on the next step, take a few minutes to look over the completed PCB very carefully, looking for poor solder joints, or sorts caused by solder bridges, as these may cause problems that lead to frustration when you try to start using your new Make It Move board.