My project uses fans and TECs to cool a plate with laser diodes. I need to control temp of the optical plate within about 2 degrees C, so not very tight really.
My plan is to use digitally controlled variable resistors to control the voltage output adjust of power supply I am using. This allows me to use the PWM and output filters of the power supply itself instead of me designing all that, the cost of all that, and this is also more efficient creating less heat in the unit. The fans and the TEC units are adjusted this way. I also use variable resistor and op amps to select input, and to do a slow fade down in laser power if temps are too high. This laser unit is used for concert use.
I want to use a Propeller 1 to do following:
Read temp from 3 i2c devices on same bus (they have address pins on temp sensors)
This is the NCT75 from on semiconductor.
Write data to 6 quad channel variable resistors.
Specifically MCP44X2 from mircochip
Need to read 3 fan tachometer outputs
Display the temp data in F or C (set via jumper), fan speeds, and what power level its outputting, status of few general outputs, very basic.
LCD-09395 from sparkfun
There are about 6 general IO items I need to do, have a few inputs I need to check and then respond with timer function when certain things happen.
Plan is to use Prop Mini, to save some layout effort, but could also put parts all on circuit board directly too.
There is existing code that is mostly correct for much of what is needed with I2C. Things like dealing with negative temp correctly and other details will need to be fixed. Also these exact devices might need some tuning to be dealt with.
I could also use help with some circuit design I need to do with the op amps, also some help picking capacitor values in places for circuit stability etc. Some of the exact chips could be changed at this point also. I picked these chips as least expensive, widely available, and just good enough for my project's needs.
Also I could use help with PCB layout. I have 3d models of how large the circuit boards can be. Its a bit tight but nothing crazy. Will likely have ~40% leftover space. Design will be mostly surface mount.
I am hoping to find someone that has worked with i2c with propeller before, and is good with both ASM and spin.
I have equivalent of 2 year degree in EE, but have not used it much in last 18 years since I was in school.
Many years ago, I think 8 years ago I took the DMX input code for prop1 and adapted it for DMX output. I had to get some help.
I am expecting the help I will need will take someone around 30-50 hrs. I am looking to start this project in about a week if I can find the right person. And want to finish it in about 3 weeks. So I will need someone able to spend min 15hrs per week.
Please send me private message with short description of relevant experience, links to past work if you have it (not required) and what your hourly rate is. Also a phone number and good times to call.
If anyone has recommendations for other good place to find the right person or company, I think that would be useful public info, so replying to this thread would make sense for that. I will also reply once I have found someone to this thread, so if I have not, the gig is available.
You don't need to be in USA, but being good with spoken english would be very helpful.
I am wanting to use the Prop1 as I am hoping that it will be very easy for me to modify the code in the future, I expect the 8 core design will make it easy to keep the code much simpler then single core cpu.
I live in Denver, Colorado, so someone nearby would be neat but thats not likely!