Hi, this is Wayne again with a topic “Projects with Ryan Slaugh”.
Over the years, different companies have made different robots, they’ve made tall robots, they’ve made short robots and they’ve made middle of the road robots. The middle of the road robot is what i’m going to choose for this first part of a two-part project. We’Re going to take this guy apart, give him some new brains and a few more sensors. The first thing i do in approaching a project of this type is to dig into the machine and see what parts i have to work with. What can i use? What can’t i use so i find all the screws and take them out of the way and all the other parts pull them out, one by one, for instance, this six volt battery we’ll come back to that. A little later i see where there’s room for different parts where things can be taken off and as i take it apart, i try to log each screw. So i don’t forget where i put them, and sometimes there can be a terrible amount of screws on these things once i find all the screws and pull them out, we’ll pull this robot apart and we’ll see just what’s inside the body part comes across comes apart In two pieces, the head dome is a separate piece.
I see here that there’s some lights in the eyes of the robot two little leds here, those might come in handy later. I might leave them in just for a little fun. I start pulling wires off the main board and from the different sensors and different inputs and outputs, i’m not too worried about keeping the wires intact. I can cut them apart at this point because i’m going to be replacing most of it, the arms of this robot, while not mechanically functional, really are neat and i’ll, probably use them in the final project we can see here on the back of the body.
We have some voltage connectors some power input and output that may come in handy later for charging. Here we see the actual main board of the robot, those two guys there are the motor control units that this used. Here’S some processor boards and a tape deck the bottom part are where the motors are located. There’S two motors and the motor units are in this are really in good shape, so we’ll keep and use those for the remainder of the project, but we do need to get the main board and the tape deck out of the way. These old robots use a tape deck to record their movements and programs, but we don’t need to use that here, but don’t get rid of it.
It’S always nice to keep these for spare parts. The first thing i’ll do is take some tests to see how the motors run and from what voltage. They are six volt motors, although they can handle more and in the case of their operating current.
When the motors are going full out on the voltages, they will be pulling 300 milliamps max. When i use a design criteria, i might put in a little fudge factor there just to make sure i have enough cover to control the motors i’ll use our trusty uno. Now the uno will not be by itself in doing the motor control i’ll, also use the motor control shield. This is an excellent shield, has great inputs and outputs direct control.
I can do direction pulse width modulation. I can even sense the current from the motors. The next step is to do a little troubleshooting and write just a very simple sketch, where i can control the motor’s direction, turn them on and off and see how they react to control. This worked extremely well. I played with the bits high low and i got both motors moving in the same direction, and now i can actually put that into the final program, so this guy’s actually going to be a great motor control device and because it has extra, i o that i’m Not using, i can do bumper sensors light sensors, a myriad of things that this robot can sense in its surroundings, but this won’t be the only thing that this robot has more on that later back to the headlights or the highlights, i need to see how they’re Wired up – and i see that they’re wired in series – and they can very simply react to a 5 volt or even more input. I might separate them up a little later, though this robot is going to have a little more powerful brain, though it’s going to have a raspberry pi now raspberry pi’s don’t have a lot of an input output, so i’ll use an ala mode to give me more Capability there’s plenty of mounting space in the back shell of the robot for the raspberry pi. In fact, it looks like it was even built to go there, and i can have some cable run areas or put some panel mount connectors on the back. The uno with the motor control, can mount right to the neck right to the side of it and be easy to wire in now.
What am i going to do with this front? Part of the body? I have these two gaping holes and you know that just doesn’t look right, so i bought a little tv screen. 3.3 3.5 inch, tft lcd looks like it fits up there pretty. Well that’s going to give me a great interface into my raspberry pi. As far as this goes down here, i can just put a metal plate over our plastic plate included with this project, i’m going to use a wireless adapter and a wireless keyboard, so i can talk directly to the raspberry pi.
Let’S talk for a moment about the parts list. More importantly, i want to talk power consumption. You see we have two motors running six volts at 300 milliamps, each the arduino uno that can run six volts at about 150 milliamps, the pi at 700 milliamps and the alamo 200. So far we’re doing pretty good. On current, however, we throw in a 12 volt 300 milliamp. Sadly, the tft will not work at 6 volts how to get around that.
This leads me to use a block diagram i like using block diagrams, because i can quickly see how things interconnect. It’S not quite a schematic, but it gives me an idea of where signals are going so here we see how the raspberry pi, the ala mode, the uno, the motor driver and the lcd all connect together in reference to data lines from there. I can also notate on the diagram what the voltages of each what the requirements are for each voltage. This helps me quickly, visualize how things are connected together from there. I can add the actual voltage connections now in this case, because we had one item that needed 12 volts and the rest could use the six or even in five volt ranges, i decided to add a secondary power source, so the 12 volt battery will take the Six volt that was in the robot before and will up it to a 12 volt battery.
It will connect through the motor driver and into the lcd screen, giving them the power they need now remember. The motors themselves are actually 6 volts. However, they will work at 12..
If i worry about overdriving the motors or putting too much wear on them, i can pulse with modulate the output of the motor driver to slow them down and to give them effectively less of a voltage to worry about to power up the rest of the circuitry. I’Ll actually use a 9 volt battery 9 volts can directly be fed into an uno and for the raspberry pi i can use an lm7805 voltage regulator. Regulators take it down to 5 volts for use on that platform and again the ala mode gets 5 volts directly from the pi itself. Now one of the big concerns with this, especially using a 9 volt battery, is the current draw of the raspberry pi in the allen mode, all together with the uno and how long a nine volt battery may last.
The first thing after connecting up the circuit, would be to test how much current the system is actually taking when it’s an operation, and perhaps a parallel 9 volt will be needed to give it just a little extra life. I would make these rechargeable both in the case of the 9 volt battery and the 12 volt battery, so this system can be recharged at any time. So in this part, one of this two-part project, we got a good start at taking apart the old robot and making it ready for its new revision. We’Ve thought about power, consumption, different sensor options, processor options and put together a good start for step two or part.
Two of the project, i’ll finish up the wiring, make sure all the sensors are incorporated and then program up what the pi, the ala mode and the other uno can do together to make this robot work in the meantime, try to find your own robot or even An old rc car that you’d like to hack and put some brains into and if you have any suggestions or any questions, please leave them in the comments and again suggestions for the next part of the project to see if i can implement them by the time That comes out happy building. .