Let's Make Robots!

How to be very happy when communicating serial wireless low tech

Updated with Bonus tip! You can "easily" hook up some cheap UHF / FM whatever units to make 2 MCU's talk wireless by serial. But you need to learn some stuff, this is what I learned :)

Since I discovered this:


all has changed! I was blind, but now I can see. And I can program!

On Picaxe, in order to send with these modules, use this code:

for b0 = 0 to 255
high 3 pause 3 low 3 pause 1 serout 3,N2400, (85, 85, b0)
pause 200
next b0
goto testsender

and to recieve, use this code:

serin 7, N2400, (85,85), b0
sound 0, (b0,10) low 0
goto testreciever

- Of course adapted to your own setup etc.

The important parts here are:

high 3 pause  3 low 3 pause 1 serout 3,N2400, (85,85...


serin 7, N2400, (85,85...

Because with that combination all together, the reciever is left most happy in all states, and the result is 100% rock steady. Like in not a single bit lost in a thousand!


Bonus tip:

A) Hook up a speaker to your MCU

B) Send sound to it in a loop

C) Take off the speaker, and hook up the sender

D) Power up the reciever, and on the out-pin, hook up the speaker (and other wire to ground on the reciever)

Now do you hear sound from the reciever, punk? If not, you can rest assured that your recieving MCU will not get any signal either :)

Yes, you can start your own little radio station with these ;)


(Note that this post has changed, some of the comments below may be from earlier)

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This walk through is so funny, it ought to be in your blog as well!

Thanks. This will be the first page I revisit when I start experimenting with radio communications.

WHAT? Funny?

Well, glad to amuse :D It's not intentional! I fuckings hate trying to write stuff in english!Like trying to have my car cook me dinner or something, has to think different for the simplest of tasks.

BTW, I often wonder how on earth you got such a diverse (in lack of a better word AGAIN) english? Can I get your brain-upgrade as a pirate copy, or maby a free sample of the disk you inserted?

And even then, I would hesitate to make us all alike in here. We should be proud of our diversity. (And I know we are proud.)

I blame TV for my English education. And the spell checker in Firefox you pointed out to us.

It's your way of describing the tech stuff that obviously is just outside your grasp. I love to see you learn and teach at the same time.

More people should do that. Better than pirated brain upgrades.

This is all clearly inside my grasp! I am totally down with robots, chips and stuff! I repell your attack!

I said "just", didn't I?

Seriously: I like the howto. For all of it: language, recognizing the learning curve, the teaching AND the cool KISSS. (The extra S is for serial, put it where ever).

(you said "outside" :)
Fritsl, you are my hero. I just need to figgur out the same thing in XMOS now.

I am first wondering if one could run 2 PWM motors off of serial data. Could I hook 2 pots to ADC's on the transmitter and send something like this?

serout 0,N2400,(value1(motorA),value2(motorB))

I could set up a good loop so the receiving robot would get a constant stream of data. 


With what I am doing, noise or "init. codes" just won't work... Is there a better RF system to use? I know we are talking more money, but I gotta have a clean signal. Easy radio, maybe?

Easy radio is rock solid!

I do not see why you could not be able to send the motor-string, this is what it is all about!