Universal Bluetooth Robot Controller

This is a short section. The keypad. Not the cheapest, but was the smallest, and with my controller. Size is a factor.

The modification to this keypad was simple, I removed the header, and replaced it with wires, and moved the Bussed Resistor network to the back.

The reason for this was I wanted it to sit as flush with the case as possible, and the parts were in the way.

The blue wire was my bad, the header pins they used were giving me trouble and sure enough I pulled up the solder pad. It's happened before, but nothing I can't fix.

BEFORE : Clicking images will open in new window.

AFTER:

I could have soldered the wires to the back, but for stronger solder joints, i decided to go through the holes.

The header prior to being incased in hot glue. The loose wire is the 5v, and it gets its own female header.

I'm using the PacTec PPT-4081.

The case is sturdy, and high quality. The plastic is very strong, and if left unmodified, is water resistant, probably  water tight within reason of course. The black outer layer, is a rubber foam. Gives a good grip, with just the right firmness. This is also responsible for sealing out water and debris.

You'll notice in my pictures, the case is upside down. I did this for one main reason. Comfort. The case, when held with 2 hands, is far more comfortable upside down and used like a game controller, than right side up when used like a multimeter.

I have long slender fingers, so a wider grip is simply more comfortable. No overlapping fingers.

The front. (upside down.)

This next image is a very large one. It's the back half of the case. The 6 screws (included) fit well, and leave a nice snug fit. Very nice.

The face plate measurements aren't perfect due to the odd rounded design.

Cutting into it.

Well I don't have a whole lot of tools, and I can't say I’m proud of the job I did. I've cleaned up the edges pretty nicely, but they still aren't precision cuts.

I ended up using an old xacto blade, which I heated with a pocket torch until red. (smelled pretty foul) But it did cut it fairly well. Later holes I used a solder iron with an old oxidized head that I was going to toss otherwise. It smelled worse. But since it's below freezing outside.. what can you do.

Yup.. that's one seriously straight line. -sigh-

Jagged edges? Nothing a fresh Xacto blade can't fix.

Need a place for that keypad.

A bit of single sided foam tape to keep debris out. The holes at the top are for the Bluetooth adapter's SMA plug and it's LED's. The LED hole was just sealed with hot glue. It works fine, nothing fancy.

Below you see the 10k slide pot's hole. This wasn't originally planned, but I’m happy with how it turned out.

You can also see the holes for the thumb sticks. At first I thought I made them too large, but when I was done, I realized they were just right.

I originally intended a couple small round holes just for the joysticks to stick out, but then I decided to fit the whole thumb stick into the hole. Whatever, it works.

And now we're mounting! I used hot glue. It's cheap, easy to use, and can be removed if you mess up. Because of the size constraints, I couldn't fit special fancy brackets or breakout boards. Before you judge the project, thinking Hot Glue is amateurish, weak, or for the poor. Weigh your options. $60-$150 for special/custom brackets, or $0.25 in glue sticks. Also the hot glue keeps debris out, moisture, and adds a bit of flexibility. It'll bend rather than break.

Roving Networks RN-24-E, Class 1 100meter Bluetooth RS-232 module.

When gluing in the thumb sticks, I had to be very careful not to get any glue in the moving parts of the sticks. such as the center of the turquoise pots, or under the buttons. These sticks receive a lot more glue later on.. Let’s just say, they aren't coming out.

The keypad wires get trimmed later on. Those were just way to long.

That covers the case construction. There wasn't a whole lot to it. Just a lot of cutting. I would suggest anyone making one to use a Dremel, and a wet blade. 1 second on, 1 second off, just so you don't stink everything up, and you can get smoother edges.

PS, I’m getting a Dremel for Christmas, so future projects will look a lot cleaner.

First things first, we need an IC Socket for the MCU. Since I'll be using a 40 Pin MCU, I need a 40 pin socket. To allow for more user space, I've broken away and trimmed down the center bar for more user space in the center of the socket.

Now then, don't make the mistake I did by building the Main board first, in fact it comes last. I had to scrap the original board and start over.

You design the board to fit your case, not the other way around.

You need a PCB to attach all your goodies to right?  I've been using these. They are cheap and Flimsy, and they work fantastic. I bought 30 at once.

A Razor will trim the left over notches on the sides. Maximizing the user space without weakening it too much.

Ok, now we're going. I started attaching header pins and the socket. There are dozens of high quality guides on YouTube on how to solder, so I won't get into it.

The 3 pins in the lower left are separated and didn't solder straight as I use salvaged parts. But they work fine, and lead to the serial LCD.

Quick TIP: When soldering Right Angle Male Header pins, it's easy to use a 2×4 Female header to get the size and the angle just right. See the top of the aforementioned image. It holds the pins in place while I solder them, without burning fingers or having pins stick up.

This image here just shows the additional headers, including the 2 power pins to the Bluetooth adapter.

Now we need power. The regulator of choice? The Texas Instruments REG1117-5.

It's small, good current, and doesn't get to warm. Why more people don't use these is beyond me. I've ran it in my controller for 20 minutes straight and it barely got warm.

I like to trim off the fins for a few reasons. One being it makes it shorter, so you can actually fit it inside the IC socket. Like in my Bot Board Mini Pro 28 As seen by the lower orange arrow. Use a tool like needle nose pliers and try to straighten the pins the best you can.

The board now has regulated power.

What you're looking at here is two 10uF capacitors immediately above the 5v regulator.

The wiring is simple. 1 capacitor between the ground and Vin on the regulator, and one linking ground and Vout. This helps with various spikes, noise, and other power related issues.

The small 0.1uF (104) capacitor inside the IC socket is between the VSS and VCC. This is also to reduce noise.

The new 2 pin header above the regulator goes to the reset button. One pin to RES line on the MCU, the other to ground.

Next up, the underside. Definitely click the image to open in new window.

The pins of the IC socket are hard to see, and not all headers are soldered in. Just the corners and the needed pins.

The programming pins S_out, s_in, ATN, and GND, are all pretty straight forward, and thus use direct links using some scrap leads from trimmed resistors, capacitors etc.  The VCC and VSS have nice long leads for future links.

The capacitors and regulator has its own little mess over to the side. That Loop bit you see is the ground linking the second capacitor. It isn't pretty, but it works great.

A lot of the best things in life, aren't all that pretty.

Wiring: 2 images

Wiring, you can see I "stitch" through some of the holes. This is uncommon for me as I haven't done this in projects before. Usually I try to make the top sides as clean as possible, But since this board won't be open for display, I simply didn't care. So I did this to get the wires out of the way.

Wiring Part2:

Now it's getting hairy, we have a lot more wires going around.

The black loose wire is the ground to the controls. It's loose because I want to solder that on last, but I wanted a heavy enough wire so I didn't use my traditional kynar.

The wires inside the IC socket do go somewhere!

The larger male header at the bottom goes to the buttons and 5v, where the smaller one goes to the pots- the joysticks and slide pot

You can see I have the keypad header wired up now.

That's it for the MCU board. The only thing that you're not seeing is, the 4 analog pins, the ones immediately under the programming header, received some 0.1uF SMD capacitors. This was because I was getting a lot of noise and jumpy values.

The MCU pinout:

A bit of explanation is due.

P0-p3 goes to the 2 joystick Axis. P30 goes to the slide pot.

P31 despite being an analog pin is just being used as an input pin, should I ever need to use that analog pin, I’ll reroute the center select button to p8.

The _______ was from when I printed this out, should I need any extra notes to write down.

The 8 C/R pins are the keypads inputs/outputs. C1-C4 = column 1-4, and R5-R8 = Row 1 to Row 4, the colors are the wires of the keypad, just for personal reference. When coding, have it check if any of the columns are pressed, and then if any of the rows. Column 2, row 3, would be second button over, 3rd down.

VIN is not used, as I supplied my own 5v. But is listed for reference.

Well more stuff is getting mounted.

A 4 +1 way button stick is placed between the joysticks, and our slide pot is in place. The slide pot, for the Rover is essentially a master speed control, which increases the speed up to a multiple of 10.l So speed 1 = 6, and speed 10 = 60. Very useful, like switching gears on a car.

The craft stick section in the center, is mostly so I have something to work on, and to secure the button down a bit.

Ya it sort of looks like a face. The glue looks really bad in how it refracts the light, but cost being a factor, well worth it. And the thumb stick toppers hide the glue.

Pay more attention to the top of the next image. The controller gets its programming connector. A Female DB-9 serial connector.

There's enough spacing around the connector for the male to fit comfortably. Giving you remove the screw headers from the male end. Else you'll need an adapter.

The ground of the thumb sticks and the center stick is getting wired up.

The wiring is done in a way so UP will = 1023, and down is 0, and Right is 1023, and left is 0.. on both sticks, despite one being upside down.

The end faze. The connections are simple. The SMA Bluetooth antenna, and under it, the black dot is the reset button.

The DB9 connector. The switch is a dual rail slide switch, which switches the RX/TX of S_in/out, between the DB9 connector and the Bluetooth. This means bluetooth and the programming header can use the same MCU S_in/S_out pins, just not at the same time.

This protects the Bluetooth adapter and the PC from signals interfering with each other.

Due to a wiring goof up, I had to redo that whole mess of red wires in the center near the sticks. I wasn't able to take as many pictures and I would have liked. All the hookups have been tested with the continuity test on the multimeter, and everything is good to go.

The battery is a 2cell, 20C, 800mAh li-po, if you look close at the bottom of the case, you'll see the 3 pin charging connector sticking out.

The controller… gets a heart.

And the controller construction.. Is done.

It works, the keypad puts out values 1-16, and The LCD looks good and is very legible even with the camera's flash.