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Member Since: May 20, 2011

Country: United States

  • My drill holes displayed by VIEWplot were way off. They looked like holes for a 12 inch wide board, even though they were fine in my Eagle Layout. What I did to fix it was: instead of just opening the 7 required files in VIEWPlot, I opened all of the CAM files that were created (TXT, GTS, GTP, GTO, GTL, gpi, GBS, GBO, GBL, dri). When the Load Drill File screen popped up, I changed Number Format to 2, 4, Leading. Then after the board was displayed, I changed
    Edit->Edit_gerber/drill_drill_setup_info page Gerber parameters and Drill parameters to 2, 4, inches, leading, Integer. Not sure why I needed the .gpi and .dri files. Don’t know what they are.
    However, my x and y coordinates for the corner of the board in Eagle Layout is 0.0 but in VIEWplot x is about +0.15 inches, and my Y-coordinate is +0.01 inches. Is this normal? Looks like it moved the board over to make room for the USB connector overhang, which doesn’t even show up in the VIEWplot drawing.
    I am running Eagle 5.11.0 Light; and VIEWplot v1.5 Build ver. 1.50.1081 with latest patches applied in Windows XP. Anyone know if those X and Y coordinate offsets are a problem for the fab house? Is it going to cut the board at 0,0 or where my board layout starts at 0.15,0.01?

  • Great advice MichaelK. Seeing the pad names is a big help.

  • I just downloaded and installed Eagle 5.11.0 Light. I ran through this tutorial just fine, except when I got to the end my nets didn’t show up in PCB editor. I went back and deleted them, and recreated them. Used the Net tool to bring the green line out from the chip and from the connectors a few squares, right click on it, named it, right click again and labelled it (with the floating label per tutorial), but they are not connecting in my layout window. I check their properties and they are on the same nets (even asking me to confirm I am adding them to an existing net), but not showing connected in my board layout. All my caps are tied together (presumably to GND), so something is working. Any suggestions?

  • Dividing capacity by current draw to determine battery life is a good rule of thumb, but not exact. If you need to be more precise, the following might be useful: Battery capacity is rated over a given period of time at a given current draw. As best I can figure out from the datasheet, this one (I think) is rated at 400mA over 5 hours. But if you draw more than 400mA, you will get less than 2000mAh out of the battery. If you draw less than 400mA, you will get more than 2000mAh out of the battery (i.e. the battery will last longer than 5 hours). The difference can be quite dramatic. Most battery manufacturers include a graph in their datasheet so you can determine the exact amount of time before it goes dead in your application. Also, the more times it is discharged and recharged, the less capicity it will have. Most also include a graph of the number-of-discharges vs. battery capacity. Also, for many batteries, the deeper you discharge them before recharging, the less cycles you get out of them before they have to be replaced. Again, this is usually graphed by the manufacturer. I don’t see any graphs in this datasheet, but there are a few datapoints included. These are things you may want to consider if battery capacity and cycle life are important in your project. Have fun!

  • 25 year embedded software engineer here, trying my hand at my first hardware project since high school electronics. Starting out is overwhelming with the number of controller and logic chips out there to choose from. Thank you for narrowing down my choices with related parts on your website, notes and useful comments. It is very helpful cutting through the noise and finding a starting point.
    I’m thinking of using two 74HC595 for driving your alphnumberic LED displays in my project as discussed in other comments here. Since I need 4 displays (as well as other outputs), that means 8 of these little guys which is about the same price as a few more microcontrollers. I googled the part and found it much cheaper elsewhere. Any chance of lowering the price of the 74HC595 so I can get all my parts from you?

No public wish lists :(