RestoLynx Posted March 9, 2017 Share Posted March 9, 2017 Looking for some advice: Was thinking of using an Adafruit powerboost for my Lynx, bypassing the 9v circuitry, but the problem is that the original on/off buttons don't work then, correct? The Powerboost will switch on if the EN pin is brought to battery voltage and off if grounded, is that correct? If so could you not re-purpose the on and off button to connect the powerboost to Batt+ and GND, or are they hardwired in the flex circuit preventing that? (Of course another hacky way to do it would be to boost the 5v from the powerboost to 9v using a DC-DC converter like this, I'd lose a load of efficiency and I'd have to switch off the powerboost separately... actually.. that is a terrible idea...) Thanks Quote Link to comment Share on other sites More sharing options...
+af0l Posted March 9, 2017 Share Posted March 9, 2017 I have been struggling with the same problem. I ended up poaching a design from the net somewhere to do just what we want: It's theoretical ATM (ok, working at the protoboard), but I'm sitting on my fathers neck (he does circuits for a living), until he corrects this and makes it into something I can put into my lynxes. As for the buttons - I have ruined my flex unplugging and replugging it so many times, so I came up with this: Now I can tap into any signal I need from the flex, and most importantly, take it apart without ruining it. It includes replacing the connector on the board, but it does not take a soldering ninja to do it. On the other hand, you might be able to find the signals on board and skip this part completely... I'll report back when the circuit is done. Quote Link to comment Share on other sites More sharing options...
Level42 Posted March 9, 2017 Share Posted March 9, 2017 (edited) I solved it using a LTC2950: http://atariage.com/forums/topic/255254-the-perfect-lynx/?p=3573214 Here's the schematic I made: http://www.digikey.com/schemeit/project/lynx-power-SBA3UE82001G/ (Notice that I only used the Power On button on my "perfect" Lynx since it was very hard to cut all traces around the Power off button. Both buttons obviously need to be isolated from the original traces on the Lynx ! Also: I didn't use external LEDs for the Powerboost in the end so ignore that on the schematic. Edited March 9, 2017 by Level42 2 Quote Link to comment Share on other sites More sharing options...
+af0l Posted March 9, 2017 Share Posted March 9, 2017 I solved it using a LTC2950 ... if you can solder like a champ Quote Link to comment Share on other sites More sharing options...
RestoLynx Posted March 13, 2017 Author Share Posted March 13, 2017 How about this, it takes usb at 5v, charges an 18650 (or two if you run in parallel) and outputs 9v http://www.ebay.co.uk/itm/USB-Lithium-Li-ion-18650-Battery-Charger-Module-3-7v-4-2v-Boost-Step-Up-9V-6F22-/252555626825 Quote Link to comment Share on other sites More sharing options...
+af0l Posted March 13, 2017 Share Posted March 13, 2017 That would keep you in 9v domain, I'm not sure, but I did not want that, due ti the risks it poses... Quote Link to comment Share on other sites More sharing options...
Level42 Posted March 13, 2017 Share Posted March 13, 2017 ... if you can solder like a champ Really not so hard with the PCB....just need to be VERY careful with the glue.... 1 Quote Link to comment Share on other sites More sharing options...
+af0l Posted March 13, 2017 Share Posted March 13, 2017 Really not so hard with the PCB....just need to be VERY careful with the glue.... I have two legless nano chips that say otherwise Quote Link to comment Share on other sites More sharing options...
RestoLynx Posted May 10, 2017 Author Share Posted May 10, 2017 Ok, that 9v module didn't work, I'm guessing that it isn't supplying enough current as I get the flashing battery light. I got a Powerboost 1000c but I'm having a lot of trouble; it only seems to be capable of starting the lynx about 10-20% of the time, it's infuriating, the rest of the time the screen (McWill) just shows garbage, once it starts it stays running happily. Whether the batteries are connected or it's running off usb it's the same behaviour. I made the power wires thicker and it worked for a while(on the bench), but then when I popped it into the lynx and tidied up the wires it went back to its old ways. I'd appreciate any thoughts you might have, ask me questions, I feel like I'm missing something here. Quote Link to comment Share on other sites More sharing options...
RestoLynx Posted May 10, 2017 Author Share Posted May 10, 2017 How about I bypass D9, the reverse protection diode? that should get me another 0.7V if I'm at the lower limit of voltage? I'm not going to be using the AC adaptor, or AA batteries and I can remove the bypass if I decide to go back. Is this a terrible idea or a great solution?!! Quote Link to comment Share on other sites More sharing options...
+af0l Posted May 10, 2017 Share Posted May 10, 2017 How strong is your psu? Quote Link to comment Share on other sites More sharing options...
RestoLynx Posted May 10, 2017 Author Share Posted May 10, 2017 How strong is your psu? It's 2 Amps, which should be enough. The behaviour is the same whether it is running from usb or the charged LiIon batteries. Quote Link to comment Share on other sites More sharing options...
+af0l Posted May 11, 2017 Share Posted May 11, 2017 Hmm, 2 Amps should be ok. It also happens to me sometimes, although much, much less frequently... Quote Link to comment Share on other sites More sharing options...
+af0l Posted May 11, 2017 Share Posted May 11, 2017 OH! Now I see it! I don't have EN connected, I just ground it when I want to disable the Powerboost. I don't think you should be connecting it to battery voltage That's: EN --- GND = OFF EN --- NC = ON Quote Link to comment Share on other sites More sharing options...
RestoLynx Posted May 11, 2017 Author Share Posted May 11, 2017 (edited) Thanks for the reply I didn't have the EN connected to ground . Perhaps I should forget about using the 9v side in the Lynx and just put the powerboost straight into the 5V side of the circuit, across C41; this would eliminate the voltage losses. I think the only downside is that I lose the On|Off button functionality (the reason I started this thread!), but I can hack something together using the EN pins and a switch or re-purpose the existing On|Off buttons. Thoughts? Edited May 11, 2017 by RestoLynx Quote Link to comment Share on other sites More sharing options...
+af0l Posted May 11, 2017 Share Posted May 11, 2017 Correct. 9V is a silent killer, like high blood pressure. It's fine - until it isn't. If I ever get my father to actually produce the circuit for on/off, I can make a small run of them for those interested... 1 Quote Link to comment Share on other sites More sharing options...
RestoLynx Posted May 12, 2017 Author Share Posted May 12, 2017 Done and working perfectly!! 5V across C41 and it is running well. At the moment I' switching it off by connecting the EN to GND (see below), I'll put in a switch in a while. As an aside; I measured voltage across C41 when i was putting 5V into the 9V side, and it was 4.6V. Quote Link to comment Share on other sites More sharing options...
+af0l Posted May 12, 2017 Share Posted May 12, 2017 Splendid! Meanwhile I talked to my old man - he is prepared to do the design and prepere the pcb with simple on-off logic. Would you be interested in that? I should probably start a poll or sometning to see how many of us would need this, so we can have it made in a single run... Quote Link to comment Share on other sites More sharing options...
RestoLynx Posted May 12, 2017 Author Share Posted May 12, 2017 I'd be interested, but you are looking at a very small subset of people who have upgraded their Lynxs! (For people looking at this thread in the future : The batteries I used were two 18650s from a drill battery pack, running in parallel) Quote Link to comment Share on other sites More sharing options...
+af0l Posted May 12, 2017 Share Posted May 12, 2017 Well, I have three of them... It hould also be a simple thing (as you can see form a schematics above). Maybe if we just get the resistor values correct, people can make their own. Quote Link to comment Share on other sites More sharing options...
cowdog360 Posted May 19, 2017 Share Posted May 19, 2017 I'll also talk to my engineer buddy. Maybe we can just have one board that has charging, boost and power latch. Sent from my SAMSUNG-SM-G935A using Tapatalk 1 Quote Link to comment Share on other sites More sharing options...
+af0l Posted May 20, 2017 Share Posted May 20, 2017 Yep, I thought of that too... Talked to father about it, but he wasn't too enthustiastic about it - the price/preformance of the Poweboost is hard to beat at these volumes... Quote Link to comment Share on other sites More sharing options...
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