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Shelves on Wheels

Shelves on Wheels

Jan 16, 2016

I scored some used shelving 18” x 36” x 72” for $10 bucks from an onsite auction of a closed furniture store. Space is at a preimum in my house and garage. I wanted to put some wheels on the shelves so I can move them around the garage. Wow they’re on sale for $55 bucks at HomeDepot. (oops online + exorbitant shipping) These are significantly stronger shelves than the plastic and metal ones that are only a few dollars less expensive. I bought a 4×8 sheet of 3/8 inch plywood. Homedepot was kind enough to rip it to my specifications. I bought a dolly on sale at Harbor Freight (HF) for twelve bucks that I salvaged both the casters and carriage bolts and nuts. I want to put wheels on these shelves. I start with a diagram of my idea. It was very helpful in describing the cuts I wanted from the HomeDepot saw cuts. I keep a project journal with graph style pages. Two pieces of 3/8” plywood. The bottom piece is 1” wider on all four sides. This will fit just inside the metal colums of the shelving unit. Clamped for curing over night at least ten hours. I used full tube of “Liquid Nails”   Bummer! Surprised that the liquid nails didn’t hold. Well anyway I’m forging on bolting the casters to the two pieces of plywood.   I clamp a piece of the salvaged HF dolly in place to use as a drill guide for the caster cariage bolts. Casters attached surrounded by the dregs of the salvaged HF dolly. A detail of how the shelving fits snugly over the top piece resting on the bottom. The custom shelving dolly raises the shelves a little less than 4 inches. Looking good. They seem pretty stable. Time will...

Imsai Power Supply Rebuild

Imsai Power Supply Rebuild

Dec 13, 2014

Recently, well once in a while in the last couple years, I’ve had the urge to rebuild some of my old CP/M equipment. Back in the day, the late 70s and early 80s, I ran some California Computer Systems (CCS), CompuPro (aka Godbout and Visan) equipment for a public bulletin board system. Also used these in business mainly for word processing but spread sheets too. I also used my father’s old Imsai S-100 equipment mostly for playing Startrek. I’ve recently been able to boot the CCS and CompuPro systems, however the Imsai was the worse for wear. It blew it’s fuse protection. My house through the years suffered a fire with resultant water damage as well as an ice storm that caused some flooding during the thaw. As you can see in the following pictures the damage isn’t totally catastrophic but significant. I’ve removed the card edge guide rails and the mounting hardware holding the PS-28U unregulated power supply sub assembly to the main chassis. The power supply with capacitors removed.Main frame before cleaning. Interesting, this image from my original Imsai documentation shows what appears to be a half wave rectifier, see heatsync near large capacitors, with two diodes. The image above of my actual board has four diodes. The documentation text does indicate four (4) diodes for a full wave bridge rectifier. Although the water damage, really just some mudding of the dust, was minimal I thought the capacitors may have shorted or leaked, note the white oxide near the connection holes. The diodes near the lower left in this image are two different kinds, the documentation specifics four (4) of the same diodes MOT MR 501. The outer locations CR4 and CR7 are the correct diodes specified while the center two (2) diodes were HEP 7520. Using the diode test setting on my digital VOM I found that the two MR 501s at CR4 and CF7 were shorted. Checking a few substitution charts I came up with a diode I had on hand an IN5408. I replaced all four to have a matched set. Although mechanically very well connected I found two of the diodes in the bridge rectifier with cold solder...

Nagios Thermometer

Nagios Thermometer

Aug 17, 2013

Nagios is an open source IT Infrastructure monitoring system. It is mature, widely used, supported, flexible and extensible. Perhaps the industry standard. Nagios at Home I use Nagios on my LAN at home to monitor Remote virtual machines that host my personal blogs business sites Status of Raid arrays Linux Microsoft Server 2008r2 Disk space availability on multiMedia server Asterisk PBX status for phone(s) Temperature at home indoors outdoors … Here is my main ‘rack’ at home. NerdDoro ePhidgety – Phidgets, MySQL C++ Server 2008R2 Fedora fc.16 – LAMP stack CentOS Asterisk (retiring PBX) Wireless phone base station Grandstream HT502 ATA Monitor/Keyboard 4 way switch RaspBerryPi (new Asterisk PBX) UPS Future CNC project likes extra slot in monitor switch. Note NEMA stepper motors. Display of Nagios monitored services including temperature from two separate sensors shown in this status screen. (click image to enlarge) The yellow highlighted line indicating warning, and the line above are temperature readings. The boxes to the left of each with the diagonal red line indicate not to send alerts. Nagios provides me email updates like this one when my Asterisk PBX, pisterisk, went down. Subject: ** PROBLEM Host Alert: pisterisk is DOWN ** ***** Nagios ***** Notification Type: PROBLEM Host: pisterisk State: DOWN Address: 192.168.1.220 Info: CRITICAL - Host Unreachable (192.168.1.220) Date/Time: Mon Aug 19 11:01:12 MST 2013 And this email informing me that the problem is resolved, that pisterisk is back up: Subject: ** RECOVERY Host Alert: pisterisk is UP ** ***** Nagios ***** Notification Type: RECOVERY Host: pisterisk State: UP Address: 192.168.1.220 Info: PING OK - Packet loss = 0%, RTA = 0.68 ms Date/Time: Mon Aug 19 11:03:02 MST 2013 Nagios Thermometer This article assumes you have a working Nagios system and have some familiarity with Nagios configuration. This blog post will explain how I monitor temperature with Nagios using a hardware sensor compatible with my HomeAmation MS Windows 8 and Windows Phone 8 projects. Previously I’ve published a couple projects that can deliver XML suitable for this Nagios plugin. A netduino temperature sensor can be found on gitHub as HomeAmationNetDuino and my Parallax Propeller project NerdDoro source is available on github as nerdDoro it produces similar...