How do I test RF using BOE?

PureGrain · 2006-11-24 20:57

I have a small emitter and receiver I took from a couple of my kids small toys. These are working as i tested them in the devices before starting to scavage them. My question is, how would I know which peices to take from the parts I scavaged and also how would I connect them to the BOE to test them?

I think I figured out which part is the receiver by looking to see that the antenna is connected to it. So that may be figured out, but how would I connect this to the BOE and is there a + or - way of connection? If so how or where could I find out how to tell?

I know this is alot but I am a total newb to this stuff and just looking for some sort of small hints. As I wait i will try to figure it out on my own, I just like to get help when I can to speed up my process. ;o)

Thanks in advance.

Kevin Wood · 2006-11-25 00:33

If you can post some photos, it would be easier to give advice.

One thing that you could try doing is drawing out a rough schematic by looking up the parts, and seeing what connects to what. A multimeter would help here, as you could do continuity & voltage checks.

As far as the reciever, it should only need power to receive, and you would be looking for an output pin for the signal interface to a servo or motor.

PureGrain · 2006-11-25 02:04

One problem I am having with this is, the device I am using come out of a SMALL motorcycle (West Coast Chopper) which has to be the smallest thing ever. One other thing that is making it dif to figure out is that it uses a small battery pack that charges two smaller batteries that powers the small servos that makes the motorcycle work.

These micro resistors and parts are making it hard for me to manage this project since I am a newb to all this.

I took the small white peice that looks like a coil off the main board on the small device and connected it too the BOE as you will see in the photo.

I connected it and used this code to make it operate. I am getting some readings off of it but when I use the transmitter I get nothing diff.

' {$STAMP BS2}
' {$PBASIC 2.5}
RcPin PIN 10
time VAR Word
DO
PULSIN 10, 1, time
time = time/8
DEBUG ? time
PAUSE 1000
LOOP

Now, since I have several of these small devices and only one transmitter, I checked to be sure that using either one did not make a diff. Which it did not. The transmitter I have is for 49MHz. I used the receiver out of the 27MHz device and the 49MHz device with no diff at all on the readings. Maybe someone can point me in the direction of what I need to do. Should I buy something that will work out of the box? I think it is more fun to get this working since it is a challenge so gimme your opinions please.

I also used this code I found in another thread and have it working giving me some readings as well but not when using the transmitter, I think this is just some random frequency it is picking up.

' {$STAMP BS2}
' {$PBASIC 2.5}
Pulse PIN 10 ' pulse input pin
#SELECT $STAMP
#CASE BS2, BS2E, BS2PE
Scale CON $200 ' 2.0 us per unit
#CASE BS2SX, BS2P
Scale CON $0CC ' 0.8 us per unit
#CASE BS2PX
Scale CON $0CF ' 0.81 us per unit
#ENDSELECT
time VAR Word
Main:
PULSIN Pulse, 1, time ' measure positive pulse
IF (time > 0) THEN ' if not 0
DEBUG HOME,
DEC time, " units ", CLREOL ' display raw input
time = time */ Scale ' adjust for Stamp
DEBUG CR,
DEC time, " us " ' display microseconds
ELSE
DEBUG CLS, "Out of Range" ' else error message
ENDIF
PAUSE 200
GOTO Main
END

ANy help would be great and i hope the pics come out well, because my camera is good but I am just not sure why the pics came out so bad.

PureGrain · 2006-11-25 22:43

Ok, I have figured out that I am not using all the parts needed. It seems that I will need to learn more about what I am trying to do before I can use these parts. I did get a wild hair since someone said that the peices from a ZipZap car would work well; I went out and purchased one of them to see. I cannot seem to bring myself to take this little booger apart to scavage parts because it is working fine and my cat loves it. ;o)

I will wait for it to break or just purchase another another one.

If anyone has any idea of how to make the parts in the pic work or have any idea how to make a receiver for the transmitters I would appreciate the help. I would much rather take the time to build something rather than to use something pre-made. Afterall I am trying to learn this stuff. ;o)

Kevin Wood · 2006-11-25 23:20

I think you misunderstood the original intent of the advice. Instead of taking the receiver modules apart, and trying to recreate the circuit, interface the whole module to your BS2.

You'll need power for the module, and look for the interface connections to the ZipZap motors. These should have the control signals for the motors.

PureGrain · 2006-11-26 00:32

Kevin Wood said...
I think you misunderstood the original intent of the advice. Instead of taking the receiver modules apart, and trying to recreate the circuit, interface the whole module to your BS2.

You'll need power for the module, and look for the interface connections to the ZipZap motors. These should have the control signals for the motors.

I did misunderstand for sure. The pics of the original device is out of a small motorcycle which powers two small servos from it's own power source. Has all the parts stilll included. I will just have to figure out how to get it to work with the boe-bot. Since it has it's own power source of rechargable batteries I am affraid to hook it up and fry something.

The ZipZap is still together as I am happy with playing around with it at the moment. Making some changes to it and modding it seems to be a bit of fun as well as my original idea. I intend on using one at a later date once my cat destroys this one as we play with it. ;o)

Thanks for all your help.

Kevin Wood · 2006-11-26 02:49

Okay, let's say that you had a Boe-Bot that you wanted to make remote controlled, using the ZipZap parts. You pull all of the parts out of the chassis, set them on your kitchen table, and hook up the receiver module, batteries, and wheel servos. When you use the rc transmitter, the servos spin back and forth, stop & go, but the parts are just sitting there on your table.

Now, if you took those parts, mounted them to a chassis, and added some wheels, you would have an rc vehicle. If you mounted all of this on your Boe-Bot, and replaced the Boe-Bot servos with the rc servos, you would have an rc Boe-Bot. If the signal going to the rc servos is compatible with the Boe-Bot servos, you could disconnect the rc servo, and connect the wires to the Boe-Bot servos, achieving the same result.

If you wanted the Stamp to read the signal that the receiver module sends to the rc servo, you would disconnect the signal wire from the servo, and connect it to a pin (with proper compoonents) on the BS2. You would then use one of the "input" commands to read the value of the signal, which you could then process with the stamp.

So, in a pretend circuit, the servo signal is connected to BS2 pin 1, and there are LEDs connected to pins 10, 11, 12. Depending on the values you read from the transmitter, you could turn the LEDs on/off in various combinations.

The thing you have going for you here is that once you remove the plastic shell of the ZipZap, there are only so many connections. Usually, in a dc circuit, red wires will be voltage, black will be ground, and a different color will be a signal line. With an inexpensive multimeter, you can easily locate the power connections, and trace out circuit connections using continuity tests.

PureGrain · 2006-11-26 03:59

Ok, I think I got it. I was just concered by plugging this into the BOE I would screw up something. Maybe I should just go back to the basics of the book and read up on what connects to what so I can have a better understanding of what I am doing. ;o)

I am a Linux Sys Admin during the day and a freelance web design/programmer in my spare time. This is just a hobby for me and my kids when we have time. I just need to tackle it a bit harder. Thanks again!

Kevin Wood · 2006-11-26 04:31

Which books are you using for reference? The "What's a Microcontroller" manual is good for basics, and the "Boe-Bot" manual will help you with robot concepts. There is also an IR book for the Boe-Bot that may be of use for remote control.

If you need an intro on electronics, you could try "Getting Started in Electronics", by Forrest Mims:

www.forrestmims.com

It's heavily illustrated, so your kids will probably pick up the concepts from it as well.

How do I test RF using BOE?

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