tag:blogger.com,1999:blog-18492728122947978562009-10-13T19:29:14.049-06:00Mind the toves. They can be a bit slithy. Don't even get me started on the borogoves.karlhttp://www.blogger.com/profile/07898918204960624055noreply@blogger.comBlogger6125tag:blogger.com,1999:blog-1849272812294797856.post-41095619310577670382008-04-09T02:39:00.004-06:002008-04-09T09:05:02.000-06:00

My latest struggle with the PID project has been getting the LCD menu system to work right. I was able to get the basic readout, showing temp, target temp, machine uptime, and heat power pretty easily. But I wanted to have a way to change the target, show the PID internal values, enter a standby mode, and adjust backlight level. I put some plain buttons in my project box and got them to work with

karlhttp://www.blogger.com/profile/07898918204960624055noreply@blogger.com0tag:blogger.com,1999:blog-1849272812294797856.post-54313444611661268142008-03-22T16:09:00.005-06:002008-03-22T16:37:55.673-06:00

(This post refers to software from the Bare Bones Coffee Controller project by Tim Hirzel on the Arduino playground.)So, I think I solved the problem with the temp sensing (see previous post). The thing that seems to have done it is to change the update interval to 2x per second from 5x:#define PID_UPDATE_INTERVAL 500 // millisecondsI re-read the PID without a PhD article, and it talks about

karlhttp://www.blogger.com/profile/07898918204960624055noreply@blogger.com0tag:blogger.com,1999:blog-1849272812294797856.post-57196544074454174142008-03-07T14:45:00.000-07:002008-03-21T17:14:16.767-06:00

When I first got my Silvia espresso machine about three years ago, I was really interested in all the mods people were doing. I did the pressure modification because it was relatively easy, cheap, and it seemed to me that it would improve my espresso. I really wanted to install a PID too, but I stopped short because using a commercial PID controller seemed overly expensive to me. So I learned to

karlhttp://www.blogger.com/profile/07898918204960624055noreply@blogger.com0tag:blogger.com,1999:blog-1849272812294797856.post-84734881096376693862008-03-21T16:19:00.000-06:002008-03-21T17:10:36.833-06:00

Here's a little problem I'm having with the PID. My temp spikes every time the Arduino turns on the digital pin connected to the SSR (to turn on the heater). Here's what the graph looks like:The measured temp goes up a couple of degrees when the Arduino is driving a digital pin attached to the SSR. Obviously, the actual temp isn't doing this. You can see that the duration of the error corresponds

karlhttp://www.blogger.com/profile/07898918204960624055noreply@blogger.com0tag:blogger.com,1999:blog-1849272812294797856.post-85979515736430392882008-03-05T17:51:00.000-07:002008-03-06T21:43:53.226-07:00

This is the beginning of my blog to talk about my "personal" projects. The one I'm on right now is putting a PID controller on my Silvia espresso machine, using on the Arduino microcontroller. I'm basing it on work done by Tim Hirzel at the Arduino playground.The basic idea is to replace the stock brew thermostat with a solid state relay (SSR) to control the boiler heater. The SSR is controlled

karlhttp://www.blogger.com/profile/07898918204960624055noreply@blogger.com2tag:blogger.com,1999:blog-1849272812294797856.post-46128154634317449262008-03-06T21:07:00.000-07:002008-03-06T21:32:57.933-07:00

I saw this post by Clive Thompson yesterday on Wired. It really sums up a lot of what I love about tweaking and tinkering with stuff. I get a lot of intellectual stimulation from learning about stuff and how to fix it. I also like the idea of reusing things that would otherwise go in the landfill and not buying new unless I have to.

karlhttp://www.blogger.com/profile/07898918204960624055noreply@blogger.com0