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randytsuch wrote:
I thought about my fan issues yesterday, and decided against trying something with x10. I think it would have been a slick solution, but the problem with digital dimmers is that you get a limited number of discrete steps. I am used to using a analog dimmer, where you have "infinite" steps.

In practice, a x10 digital dimmer may have fine enough resolution to work, but I don't want to spend the money to find out.

This leads me to Bill's suggestion to rectify my AC, and then use a mosfet controlled by one of the PWM outputs to control fan speed.

This will work for me, and I am planning to do this to get my setup working, but it is not a very universal solution. It works for anyone with a P1 or Pumper, but not many others.

In the future, I may try for a different, more universal solution. I am planning to use an Arduino to replace my PID on my espresso machine, and for that application, will need to figure out how to control the pump pressure. I do it now manually with a light dimmer, so it is very similar to this problem, and I can't (at least I don't think I can) feed that pump DC.


Randy

mikeasr wrote:
My displayed temps are off. How do I correct?

milowebailey wrote:

Randy

A triac will work better. Here is a circuit that will work with the arduino. You will need to sense the zero crossing of the AC line and then trigger the triac with an output. This would give you analog control. The later hottops use this technology to contol the fan and, I think the heater.

http://www.andrew...age_id=445

Another meathod here

http://www.techli...ontrol.htm

another here
https://www.onsem...8011-D.PDF

seedlings wrote:
This is a Variable Voltage Regulator for DC:

I use it in tube guitar amps to lower the rail voltage from 400+ volts down to about 40V and everywhere in between. If R2 is 10% of the pot, so your lower voltage limit will be 10% of your supply voltage. You won't need D2. Q2 is NTE2377, which is kind of expensive, but I robbed a mosfet from a defunct cpu power supply. Other known workers are MPT6N60E, IRF740B, STF9NK60ZD.

CHAD

milowebailey wrote:
Here is a circuit that will work with the arduino. You will need to sense the zero crossing of the AC line and then trigger the triac with an output.

JimG wrote:
I've been playing around with LCD displays and pushbuttons lately. The result is a beta version of an I2C interface board. On the interface board are mounted four pushbuttons, a 16-pin header for directly connecting a typical 16 x 2 LCD, and an RJ-11 socket.

The idea for this came from JeeLabs' LCD Plug. To that basic idea, I added pushbuttons and the RJ-11 socket. I had to use a 16-bit port expander instead of 8-bit, though, since I added the buttons. The interface board connects via 4 conductor phone cable to the I2C header on Version 3.00 of the TC4 shield.

I had a couple of prototypes built by BatchPCB and have been testing them this weekend. The interface board works fine at the end of a 30"length of phone cable (I haven't tried going any longer).

I'm not sure what I'll do with 4 buttons. I modified the development version of the Bourbon code to watch for button presses. Right now, I've got it set up to reset the elapsed time to zero upon any button press.

I am using my TC4 as a standalone roast monitor and manual heater controller for my Hottop, and being able to reset the timer is pretty handy.

If there's interest, I can post photos and other information.

Jim

rama wrote:
I added a bit of code to the Processing bits to include a RoR average (currently set to a 10 second window). Seems to help me a lot when the RoR values are erratic.

randytsuch wrote:
Jim
I'm interested. I just bought an old alpenrost to use an an arduino project, I want to play with a drum type roaster.
The alpenroast needs a four output discretes, and I have four left, but I was looking at adding an I2C 8 bit port expander to do it. If you already have this, I would like to see how you did it.

JimG wrote:

I'll get some pictures posted soon. Here's an image of the board layout:

EDIT: OK, I give up. I guess I'm not smart enough to attach an image.

EDIT: Links to PDF's showing the board and schematic:
http://code.googl...00.sch.pdf
http://code.googl...00.brd.pdf

Jim

seedlings wrote:
Jim, could you email me one of yon pictures? seedlingscoffee@gmail.com

randytsuch wrote:
I am planning to "borrow" some of your eerom and 23017 code for the next set of enhancements to Kona.

randytsuch wrote:
One minor suggestion for the LCD board, you could bring the unused 23017 IO pins to holes, so it would be easy to connect them to something else.