Yes it seems after testing the high logic is not open.
So I had to make up some interface between the two.
I use the
TTL input from Txd off the bluetooth module
TTL output to Rxd to echo comnmands to test if polou is running.
I use DTR to the reset on the pololu 8
And I added a battery level cut off circuit to DSR to indicate battery needs chagring.
The bluetooth module is all TTL 3.3v
I ended up making a circuit for the 3.3v to 5v level (off the net) using an N channel Mosfet.
Knowing you had a 4.7K pull up, thanks for that, I added a 4.7K in the 3.3 side to match it.
So that works good and we get 3.3v up to 5v levels.
The 5v to 3.3v was just a resistor pair (68K and 115K to gnd) tapped centre to drop 5 to 3.3v
The battery monitor to 3.3v was a bit messy
3.9v zener driving an NPN and NPN follower, that then switches the mosfet for a sharp enough logic swithing to the DSR at the battery level we want (4.9 v cutoff)
But the things take me hrs to solder up and I cant afford the time.
What I need is a board that has 3.3 to 5v logic translation
Servo plug pins to plug to it like the pololo, same as the BT module has too.
Having 4 throughputs.
TTL5v out to 3.3vRxd
TTL5v In from 3.3vTxd
DTR3.3v to TTL5v Reset
The 4th so I can plug in my battery monitor circuit from it.
Your USB to serial board seems to do this, or does it.
I am not certain, if you can direct me on that info, or to another board I can use to to do this job.
I need to cut out soldering.
Ive been making the gear I sell for 2-1/2 years, the more we make, the more orders we get.
(it is prefered equipment for a multinational franchise chain)
I meet ETA's on delivery by the skin of my teeth.
I have to cut down labour at ever chance to increase ouput.
The relays and such in the other thread would cut out a lot for me and be a bonus.
Having an volt interface I can just plug in with servo leads
(got a crimper, terminals and 2 x 1 kilometre rolls of servo wire.)
And that would carve off the other big time consumer for me.
So if you have something I can use now, let me know and some idea of how to make us of it.
Or can you make this for me.