- Tue Feb 21, 2012 8:48 am
#140123
I should preface this by saying, I'm not an EE, and I have no real background in electronics. I know some basics, just enough to be dangerous really. I've been breaking my electronic toys since I was about 8 (stole my dad's radioshack soldering iron to "fix" my RC truck). 25 years later, I'm still breaking my toys, they're just more expensive toys. Still using a radioshack iron.
anyway - I have a problem to solve that may actually be really simple. It's beyond the experience I have, the problem is I don't even know what question to ask. So I'll explain what I'm trying to do instead.
I'm converting a signal for a gas gauge, to use a single low-resistance sender (3-75 ohms) with a gauge that expects two, high resistance senders (~200-700ohms). I believe the gauge sends a 5v Vref signal to each sender (which is just a resistor network and a float), which are sent to two seperate ADC convetors (16 bit! overkill?) and computed inside the gauge to move a stepper motor, which moves the needle.
I do have 2 senders, but they are wired in series (which I cannot change for other reasons), and I believe (but I need to verify) that the total resistance is 3-75 ohms. I can hook up the vref to my series-wired senders easily enough, but the output voltage would be too high, the curve wouldn't fit, and I'd only have one output. So I need help.
So, it seems simple enough - take some voltage input, Nv-5v, from my series-wired senders, and output a 0-5v curve to two ADC inputs. suggestions? I spent some time searching for ideas, but I'm a bit lost. Sometimes knowing what question to ask is harder than solving the question itself.
I have *some* control over the ADC transfer curve, in software - but, I'd like to get it as close as possible with hardware first.
anyway - I have a problem to solve that may actually be really simple. It's beyond the experience I have, the problem is I don't even know what question to ask. So I'll explain what I'm trying to do instead.
I'm converting a signal for a gas gauge, to use a single low-resistance sender (3-75 ohms) with a gauge that expects two, high resistance senders (~200-700ohms). I believe the gauge sends a 5v Vref signal to each sender (which is just a resistor network and a float), which are sent to two seperate ADC convetors (16 bit! overkill?) and computed inside the gauge to move a stepper motor, which moves the needle.
I do have 2 senders, but they are wired in series (which I cannot change for other reasons), and I believe (but I need to verify) that the total resistance is 3-75 ohms. I can hook up the vref to my series-wired senders easily enough, but the output voltage would be too high, the curve wouldn't fit, and I'd only have one output. So I need help.
So, it seems simple enough - take some voltage input, Nv-5v, from my series-wired senders, and output a 0-5v curve to two ADC inputs. suggestions? I spent some time searching for ideas, but I'm a bit lost. Sometimes knowing what question to ask is harder than solving the question itself.
I have *some* control over the ADC transfer curve, in software - but, I'd like to get it as close as possible with hardware first.