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Current time:0:00Total duration:10:02

Video transcript

this is our L 298 compact motor driver we're going to use it to control the motors on our little bitsy bot we're going to control those hair dryer motor speed and direction using this guy it's going to allow us to switch the high voltage we need for the motor and the high current with our low voltage and low current from our microcontroller which is called the Arduino so the Arduino here has a bunch of different pin outs we can use those to connect to the motor controller and control the motor it also has a USB cord that we can plug in our USB socket we can plug into our computer so we can program it to tell the motor controller what to do so the motor we're gonna use is this guy it's a basically a hair dryer motor and it's going to be used as our wheels on the Bitsey bot and so it'll allow us to drive around and do all kinds of things and the motor controller allows us to control two of these so that's one of the reasons we selected it we also chose it because it was a kit so to get started we need to use a rosin core so we're using a rosin core 60/40 solder and that a little the rosin core allows it to stick a little bit better so the first thing we're going to do is select our resistors for our L 298 chip and the resistors are going to be those first resistor are 47 K ohm resistors and you can tell they're 47 K ohm because like all resistors they have stripes on them that indicate what their resistance level is so these particular ones are yellow purple orange and gold and so we put the LED or we put the I should say the resistors in and we've bent their leads so that the resistors stay snug against the board and we're going to heat the solder pad that the resistors lead goes through so it takes a little while to get the hang of it but we're just heating the the soldering pads that the lead is going through and trying to make sure that they get just enough solder to wick all the way around the lead and make a clean connection sometimes it's it's tough to get the the point of the soldering iron just right so that you can get the the heat on the on the pad but we'll get it there and it's important to keep the tip of the soldering iron clean so now works inspecting the connections to make sure that they are solid and that our components are where they should be on the board and you can see that the solder has flowed through and is is there's a good connection on each of the of the resistors so we're gonna go ahead and trim off those leads will use a nipper pliers you want to trim them as close to the board as you possibly can you still want to of course leave the the solder connection intact alright so now we're going to install our next two resistors and we'll do these a little bit more quickly because you've already seen how we connect resistors these resistors are 2.2 K ohm resistors and they are used to protect our indicator LEDs you can see them in the top of the screen there the the green and the red ones and these are indicated you can tell they're 2.2 K because they're red red red and gold and so we just splayed the leads of the resistors there so we could hold them in place and then of course we soldered them down and those resistors are put in place vertically instead of horizontally because there's not as much space alright so now we're going to install our flyback diodes these diodes are going to protect our circuit from current that could come back from the motors these diodes are the same types of diets that you would use in say a bridge rectifier they it's important that they're installed in a particular way so you can see there's a little square at the underneath via our on the right hand side of the diode marking and that square shows that you should line up the silver stripe on the diode with that square so the silver stripes should face the out should be closest to the outside of the board and that means that the diodes are in the correct location and as we know diodes function like valves and they only allow the electricity to flow in one direction so it is important that they're installed in the correct way you can see how that diode is not sitting quite flat so I'm going to take my pliers and push it in the rest of the way it's important that the components on the board sit flush so then we'll just bend the leads out like we did with the other components and make sure they're all lined up appropriately and it's important again to keep the leads away from each other she don't want them to be touching when you solder them down and so we're just verifying that the leads are there and that the diodes are flush against the board and they are and so we'll solder them in place and then add the other six diodes that are required for protecting our board so we've got those in place and they're all soldered down and we soldered each of the pads and so now we're just going to trim off the leads and again you want to make sure that the solder pads don't connect too to each other they should stay separate anyway we're verifying now that the solder joints look pretty good and the components are in the right orientation and they are so you can see how they're connected and how the solder has flowed around all of the leads and that none of the solder joints are touching okay so now we're going to install a filtering capacitor this is a high frequency filtering capacitor it's 0.1 micro farad's and it's bipolar which means it can be installed either direction it's not like the diodes that that care which way they go and so we're gonna bend the leads out here on this and again we'll just heat up those solder pads and solder right to the pads now it's a the pads are closed on that one so you got to be careful not to use too much solder and we'll trim the leads off so now we are going to install our light-emitting diodes these light-emitting diodes are going to allow us to see what direction the motor is turning what direction the current is flowing all right so these indicator diodes are very important it's very important that they're installed in the correct way so they have a long lead in a short lead and the short lead needs to go to towards the square pad or through the square pad and there's also a flat side on the diode that will line up with the flat side on the opposite diode and that's how you know that you have the diodes in in the correct orientation and they will also sit completely flat on the board as you can see right there when they're incorrectly so just make sure those two short leads are facing one another and that they go through the the square pads that are in the center so again we're gonna Bend those leads out and that just holds the diodes flat while we solder them in place okay now that we've got the diodes in we're going to connect our interphase socket strips these basically allow us to easily connect wires from our Arduino to the motor controller and they allow a little place for us to plug the wire in so we're going to tape these down because they're not easy to hold in place their leads aren't long enough to bend and then we're going to set them on the on the pliers to hold them in place and then we'll just solder them down so now the next step is to connect our terminal blocks so the terminal blocks will connect will allow us to connect our motors right to the lt98 controller board and will also provide us a place to get power from the board to power other components so we've got a place to do that so here's our here's where we wire our battery that's our three terminal block and then our motors are wired on the two terminal blocks and again we're taping those down just to make sure they sit flush because they tend to have a tendency to sort of fall out of the board when you're soldering them in place here's an electrolytic capacitor so now we're going to install our twenty 2 micro farad 850 volt capacitor this is an electrolytic capacitor it has a it has the the round pad needs to be connected with the positive which is the longer capacitor lead it is it is polarized and now we have our five volt regulator this is going to allow us to get 5 volts from the board and we just pushed it through and we're soldering the pads down and that 5 volt regulator will allow us to use some of the power from the board to power our Arduino and so now we've got a our l2 98 chip which is the logic chip on the board and the LT 98 chip does all of the it takes the cig it interprets the signals from the Arduino and allows the power to flow to the motors and so the l2 98 chip is really heart and soul of the of the motor controller so it can only go in in one direction and when you put the lt98 chip in you want to make sure all the leads stick through an even amount and so what I like to do is put something under the other side of the motor controller just to make sure that the pins are all coming through evenly and so it also makes a little easier to solder to and again we're just soldering right to the to the see the solder pads heating the solder pads and connecting everything alright so we're double checking to make sure there are no shorts and that all the solder connections look solid and are in our good and it looks like they are so that's a it's a good sign and you can see there are no places where the solder has gone and connected across and then you can see the top of the board all the components are sitting flush and they're in their correct locations and that's that's pretty much it that's our ell 298 motor controller that we're going to use to drive the motors on our bitsy bot