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Right after "make your own power supply" should come "make your own DMM"! I used an ICL7106 integrated A/D and 3.5 segment LCD driver. The entire circuit can be constructed using basic circuit knowledge and information in the data sheet. Not a beginner project, but certainly something to do early on in DIY that it well explained in app. notes.
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Jan 16, 2008 01:30
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Also, if anyone is building a +/- adjustable linear regulated supply, I could draw you up a quick circuit so the positive and negative voltages track (are always the same and adjusted with one potentiometer). I could also put in a ratio knob so the negative supply can be set to half (or whatever) of the positive supply. I don't know if there's a good schematic for this online, but I could draw it up for you in no time at all.
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Jan 16, 2008 19:38
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Phlegmbot posted:There's a good schematic for this online. Perfect, although a beginner wouldn't know how to decide which opamp to use. Also, making R4 adjustable would give you a ratio between the + and - rails. I've never really looked online for any simple circuits like this. I just spend the 6 minutes designing it myself. I really don't know how easy/difficult DIY electronics is and what you can find online...as DIY for me includes a bachelors degree w/ 1000+ hours in hands on labs, with a background in physics, as well.
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Jan 18, 2008 02:25
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Here's how the volume pot most likely is set up: You have 2 connections for the on off switch, and 3 for the left channel and 3 for the right. On each channel, you should have a pin that is ground, a pin that comes from the source, and one that is the attenuated output. With an ohmeter attach lead to ground, and probe around the other pins until you find the terminal that is changing it's resistance to ground when you turn the volume knob. It should approach 0 ohms when you're turning the volume knob left/down. This is the output to the amp. When you find this pin, leave the test lead on it, and take the lead off ground and put it on the other pins, and find the one that approaches 0 ohms when you turn the knob to the right. THAT pin is the input. If you can find them both, you've found the inputs to your amp 
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Mar 20, 2008 02:21
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Nerobro posted:The kind I have are 1amp. I was aware of the need to heatsink ;-) Just not that acutely aware. But a bicycle is the perfect place for a heatsink: lots of air movement! Also, maybe I didn't read your orignal post well enough, but you could put 2 LEDs in series for a 6.4V drop, which would halve the power wasted by the resistors and be closer in efficiency to a switching supply? Actually, what you should look into is to is use a 555 timer to blink the lights very quickly. 99% of LED lights do this to save power.
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Apr 2, 2008 11:42
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Well your light is certainly well thought out, and I eagerly await pictures and stories of your night rides. A night race in a cemetery with the cops showing up is probably the most exciting thing I've ever done
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Apr 3, 2008 19:29
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chocmilkrush posted:If you are looking for a company to do a PCB for you, go to http://www.acircuits.com/. The price is something like $33 for a two layer board. I think you mean Advanced Circuits at http://www.4pcb.com Similar name, but they in fact are the ones with the $33 single board student special...and it's s $5 McDonald's card now. There's a thread here about various places : http://forums.somethingawful.com/showthread.php?threadid=2773461
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Apr 7, 2008 08:26
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MAH POKEYMANS posted:Does anyone know anything about ARM processors? I have worked on an Atmel before, i love those things, but these look simply too good to be true for a lot of the bigger projects I will be soon getting into since my senior project is coming up. So does that look like a good deal? or am i being stupid and should stick to Atmel? I may have mentioned it before, but this chipset is very easy to use if you're affluent with ATmega or similar stuff, and the board feature set looks pretty good for universal projects : http://microcontrollershop.com/product_info.php?cPath=154_170_267&products_id=1414 This is the particular board that I used : https://www.priio.com/productcart/pc/viewPrd.asp?idcategory=5&idproduct=79 Depending on what you get, you may spend a good amount of time writing functions to use the I/O on the board itself,or you may find that you can download a full RTOS that takes care of most of that for you for your specific board. I had a ton of fun writing the hardware level stuff to familiarize myself with the AT91SAM7x, but if you're going to put it on the net, that FreeRTOS with TCP/IP stack is a life saver
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Sep 8, 2008 17:33
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