Bachelarius Posted May 31, 2011 Report Share Posted May 31, 2011 The batteries should fit into the grips themselves and the control board should fit snuggly into the hole in the gips of the lower body. I'm mounting the circuitry on a small length of vero-board, shouldn't be much bigger than about 15x30mm, once complete. Only thing I am unsure about is where to put the charging port and switch really, and how best to cut the grooves. Hopefully will be able to both into the bases of the grips, pointing downwards. Will cross that bridge later.. Link to post Share on other sites
Silent_Knight Posted May 31, 2011 Report Share Posted May 31, 2011 Do you have a link to the battery you will be using. I am custom building the grips and have found a very good hard wood supplier who does thin wood panels for making model boats Link to post Share on other sites
Bachelarius Posted May 31, 2011 Report Share Posted May 31, 2011 lol just ebay '3.7v lipo', they come in all shapes and sizes and cost about £2 each, sometimes less if you get more than 1. I've been looking at the crappy 15C ones. Bare in mind that it does still NEED a fair chunk of protection, at least under current protection, if you plan to charge it with a lipo charger. I personally don't trust the lipos that come with protection circuits built in. From what I have read, they do not actually save the batteries from over-discharge, they let them get past 3v and only cut them off at about 2.6v to stop them exploding... And they cost 2-3x more... Link to post Share on other sites
Stoka Posted May 31, 2011 Report Share Posted May 31, 2011 Why don't you make some kind of dump / frag pouch instead of fitting it to the gun. Look at the battery packs for RC receivers, they are 6v IIRC. Link to post Share on other sites
Silent_Knight Posted June 1, 2011 Report Share Posted June 1, 2011 I want the battery in the grip for cosmetic reasons really looked at lipo but most are too thick about 7mm or very low mah. Are you making you own heating system or using one from another device ? Link to post Share on other sites
Bachelarius Posted June 3, 2011 Report Share Posted June 3, 2011 Currently I am just using a standard pair of heat pads from the inside of a pair of USB gloves, but I hope to get some resistance wire and wind my own all the way around the mag inside the grips. Now that I have these things, I will be able to measure the resistance of the wire and match it with the right stuff, as I need it to take a multimeter to it. btw, see if this makes any sense to you: 3v cutoff circuit using an LM10 chip (audioguru's post is the good one it seems): http://www.aaroncake.net/forum/topic.asp?TOPIC_ID=8492 Link to post Share on other sites
Silent_Knight Posted June 3, 2011 Report Share Posted June 3, 2011 I have a resistance wire fact sheet but it's a hard copy will try and scan it for you Link to post Share on other sites
Bachelarius Posted June 16, 2011 Report Share Posted June 16, 2011 Hi everyone Quick update on design progress and a big (for me) question actually. I have decided to use a cheap unprotected lipo, as those 'protected' lipos only protect the thing from blowing up, not from being damaged. The charging part is easy, I can just used that 5 pin charging chip I mentioned earlier. It's surface mount, but not ridiculously small, so I should be able to handle it, just tore the circuit for that out of the datasheet. The under-voltage protection is another story however... That has been a royal pain in the *albatross* and I have found literally one example of how to build one. http://www.aaroncake.net/forum/topic.asp?TOPIC_ID=8492 (last pic on there, posted by AudioGuru) It looks ok, but the hysteresis part looks dodgy to me, does it need a diode in there as well as that resistor? If so, which way is the current even meant to be flowing there? Also, what should the resistor value be, if R1 = 470k and R2 = 33k? as those two pair up to make a steady 0.2v at 3.048V or something like that, thus triggering the cut-out then. So lets you use most of the battery's voltage without exploding. Also, is there a better or cheaper way to do this? The LM10 is quite expensive (comparatively speaking) I searched all over the place, but no luck. Only thing I found (well, stumbled across only today actually) is an adjustable voltage regulator, the LM317L what do you reckon, usable? Better alternative? Anyway, here's my most up to date circuit, would really appreciate any help you can offer! Datasheets: MCP73881: http://www.datasheetarchive.com/pdf-datasheets/Datasheets-18/DSA-357692.html LM10: http://www.datasheetcatalog.org/datasheet/nationalsemiconductor/DS005652.PDF Oh, P.S. as you can gather, I am not an EE, just someone who'se dabbled in it a little bit. So stupid, glaring errors are there by accident, please do pick me up on them! Link to post Share on other sites
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