Shaving off a couple volts...
I am in the process of wiring Walter. I have my RC receiver outputs going into a 28x but I have run out of input pins! I need to use 2 of the ADC inputs instead but the ADC's won't accept a pulsin command. Problem solved, I am using a spare 14m to do a little translating for me. The 14m will accept the last two pulsin commands and send them off to the ADC's on the 28x. Here's the deal, the two remaining channels (from the RC unit) are "bang-bang" channels --they are still servo commands but not variable, they are only centered (150), full left (225) or full right (75).
Question: I need the output of the 14m to spit out a total of 6 voltages, 3 each going into 2 of the ADC's of the 28x. This way, the adc can simply read hi, med, low. Any thoughts on how to get the 14m to spit out 3 different voltages?I am soldering my own board for this one so I have tons of room for extra componants.
@ Sat, 2008-11-29 23:34
ROFL!
@ Sat, 2008-11-29 23:27
It worked! It worked!
It's the 4 channel 4k7 resistor bridge!! Stay with me here:
The 28x accepts (4) of the pulsin signals from my RC unit and sticks them into 4 variables.
The 14m accepts (2) 3-posistion pulsin signals from my RC unit
The 14m, through it's 4-output resistor bridge, sends one of 3 signals to (2) ADC channels on the 28x
The 28x ADC channels read: 0,146 and 255! --Perfect!
And to add to this, I am even sending these 6 variables onto my 40x using the serout/ serin commands! And it works!
Thanks everybody!! --Especially Oddbot --you're schematic was the prettiest. Gold star for you!
@ Sat, 2008-11-29 20:46
I shoulda...
@ Sun, 2008-11-30 01:19
We already do!
@ Sat, 2008-11-29 18:43
I love smart people!
@ Sat, 2008-11-29 18:49
(52 days and counting)
But that would be a whole different thread
@ Sat, 2008-11-29 20:10
Hmmmm..
Didn't somebody say the geek shall inherit the earth?
@ Sat, 2008-11-29 13:49
Get (up to) THREE states from a tri-state MCU pin NOW!
As mentioned in Zanthess' blog on led arrays, a picaxe multipurpose pin can be programmed to assume any one three distinct states. I never did this before, but I came up with a one pin design for Chris' communication challenge.
The left pin is the Picaxe talking to the input pin on the Picaxe on the right. All we want the talking axe to do is:
Here are the three equivalent circuits:
I chose pulling resistors of 22 kOhm. At 5 V supply, a sinking/sourcing MCU will draw/push 0.23 mA. The voltage divider will use up half as much. I do not know the rated "impedance" of a picaxe input pin, but I imagine it is much higher than 22 kOhm. High enough not to influence the balance in the divider.
I'd like my "esteamed peers" to review this idea and, if possible, verify this pin reduction BY FIFTY PERCENT!!!
8ik
@ Sat, 2008-11-29 23:29
Pretty slick
@ Sat, 2008-11-29 14:28
Your on a roll!