Window Blinds Controller: Now with 434mhz wireless!

[kd5crs]

I have reworked my design to use 434 mhz wireless communication instead of IR. I gotta say, I'm amazed at how easy it was to set up. I use the really cheap transmitter and receiver from Sparkfun (WRL08946 and WRL08949). Learning from what other people have tried on this board, my serout is:

serout 1,N2400,("UUUUUUUUUU","WTB",5)

where WTB is the name of the particular blind to be controlled. 5 tells it to open the blind. All the Us wake up the receiver to the proper gain.

The blind then sends back a signal confirming it has moved to the new position. So far, I've done over 50 open/closes, and it hasn't missed one yet. Pretty cool.

I have also changed the motor from a gear motor to a hobby servo. That way I don't need switches for open/closed, so everything except the power cord can be stashed inside the top of the blinds themselves. Much better WAF!

On that note, has anyone ever used T-Pro servos? They have them at Hobby Partz for $3.50 each (9G servo). I was figuring on $15 per servo, so that would be one heck of a cost savings for 20 windows.

Anyway, I didn't want to seem ungrateful for all the help on my last PCB design. The reason I haven't posted a new one yet is the switch from IR to 434. It'll be a totally new board design, and a much better final product.

Thanks, this board is a fantastic resource for the new Picaxe user.

Brian

 

[manuka]

Puns galore abound - "glad you've seen the light" etc- but bravo ! Maybe shoot VElux an email ? I'm sure you'll agree that these 433 MHz units & PICAXEs are made for each other. Sorry but no experience with those servos. Stan

 

[premelec]

Torque?

Have you measured the torque you need to operate the stiffest blind? That servo is rated at about 12 oz/in - also what mechanical output linkage do you need ? Looks like a bargain! - IF it has plenty of torque..

 

[kd5crs]

Have you measured the torque you need to operate the stiffest blind? That servo is rated at about 12 oz/in - also what mechanical output linkage do you need ? Looks like a bargain! - IF it has plenty of torque..

Yep, that torque is plenty. After removing the hand-turn rod from the blinds they require very little torque to move. The mechanical linkage is simply to take one of the cross-shaped servo arms, cut it so it fits in a 3/8" drive socket, then adapt it to a 5.5mm socket which fits the hex rod in the blinds. That's actually easier than what I did with the gear motor, so wins all around.

No one has jumped on here and said "I used that servo and it set my house on fire and chased my dog" so I guess I'll try it and see.

Another question: I have run out of pins on my 08m. I'm wondering if I can make some of them be dual purpose. I have two LDRs, one facing out the window and one facing into the room. I also want 2 LEDs on the board that I can use to give status when I have the board on a bench and not hooked up to the servo. The LDR and the LEDs would never be used at the same time. So, can I hook both an LDR and an LED to each of the ADC pins without messing up either one? Turn turn on/off the LED I'd use "high pin/low pin", then to read from the LDR I'd use "readadc". Will this work and still give good readings?

Thanks!

 

[hippy]

So, can I hook both an LDR and an LED to each of the ADC pins without messing up either one?

Possibly. LDR between pin and +V, 10K(?) pulldown between pin and 0V, 330R minimum from pin to LED to 0V.

To turn LED on : HIGH <pin>
To turn LED off : INPUT <pin> or possibly LOW <pin>
To read LDR : READADC <pin>, b0

 

[manuka]

You could also consider the old LED trick of both emitting AND sensing light. It's been done with a 08M & red LED to great effect - see below.

Time wasting alert - Googling this can lead to all manner of sidetracks! Stan.

 

[Andrew Cowan]

I've had mainly good experiences with TP servos - one out of the ten or so I have used resets every time much torque is applied. I'd recommend them though - 90%+ working is worth the cost saving.

A

 

[premelec]

99cent sale today

The cheap servos referred above are on sale today 99 cents each - 8 per customer - about $1.50 per each 8pc with postage in USA... I'm about to find out if they are worth it...

3000pc this morning - SOLD OUT this afternoon.......