ZoneMikel's Blog

The first thing I did was hook this up to the connector on the jinx mcu board … this provides 5+V to the module. I saw a little bit of smoke and it bubbled up a little. I thought I had ruined it but it turns out it still functions, not sure if perfectly but it does tx/rx.

First lesson, it needs MAX 4.2v so you cannot use your 5v source !! It can run off of +2.4V to +4.2V and it needs 100mA. So If you were to use a voltage divider it might work. I used a lm317 to get a voltage source of about 3v. But if you wanted to do a voltage divider you could use a 47 ohm resistor as r1 in a voltage divider that would give you 5/47=106mA. In the basic voltage divider formula Vin*(rk/(rk+r1))=vout solving for 3v gives us 70 ohm as rk. That should give us 100mA and 3 v but you still have to make sure you wont burn up your resistors and in turn burn up the whole module.

I programed the pic to transmit at 19200 baud then I looked at the output from the other wireless module through the scope. Looks like the signal went through just fine.

The only weird thing is on either module connecting the scope to the rx or tx both give the output from the pic. So if i was transmitting on the tx pin on one module then on that same module i connected the scope to the rx pin (pin3) i would see the same signal I’m sending out. Also on the module thats receiving the signal through the air is outputting it on the tx and rx pins.

It says nothing in the datasheet about full duplex or anything so looks like we will have to experiment to figure it all out. This puts thoughts into my head about ack signals and such, I need to start thinking about how the two devices are going to communicate.