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Forum Index : Microcontroller and PC projects : CMM on Batteries?
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Poppy Guru  Joined: 25/07/2019 Location: GermanyPosts: 486 |
Hi Everyone! Does anyone have a Colour Maximite running on batteries, probably being embedded? Looking at the schematic I guess that the easiest way could be a regulated 5V battery-pack at the USB jack!?! http://geoffg.net/Images/Maximite/SchematicLarge.png I assume that the Vin should generally be right before the IC3 (TC1262) (... perhaps (ab)using J1 !?!): What do you already have yourself or think about it?   Andre ... such a GURU? | ||||
twofingers Guru Joined: 02/06/2014 Location: GermanyPosts: 1593 |
Hi Poppy, welcome to the Backshed!  The DuinoMite from Olimex is a Maximite clone I would say the simplest and cheapest way is to use a power bank (the empty case cost you 1-2€) and a 18650 LiIon battery (Samsung,Panasonic or Sony ~ 10€/2). Regards Michael causality ≠correlation ≠coincidence |
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| twofingers Guru Joined: 02/06/2014 Location: GermanyPosts: 1593 |
Hi Poppy, welcome to the Backshed! The DuinoMite from Olimex is a Maximite clone I would say the simplest and cheapest way is to use a power bank (the empty case cost you 1-2€) and a 18650 LiIon battery (Samsung,Panasonic or Sony ~ 10€/2). Regards Michael causality ≠correlation ≠coincidence |
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| Poppy Guru Joined: 25/07/2019 Location: GermanyPosts: 486 |
Thanks for the Welcome! Really nice and friendly here!  I know the Duinomite and have several of it, but I exactly mean the CMM, just for having all on board I need including colour ... except the battery support. I think the CMM is still handy enough to embed it! The costs are not so important for me, more the loss of actual energy for regulating the voltage up and down and back up and so on otherwise it would be easy to plug in a 12V lead acid battery, but at least I think the IC2 (7805) should generally be bypassed. But keeping the IC3 inline it would not make any difference in taking the USB socket or otherwise abusing the J1?!? How important is the high level on the Pin 54 (Vbus), the Chip recognizes the power on USB, but actually what does it mean when there is no traffic on D+/D-? Andre ... such a GURU? | ||||
Geoffg Guru Joined: 06/06/2011 Location: AustraliaPosts: 3292 |
It would be best to just feed in +5V on CON2 (the USB socket) for a couple of reasons. First the PIC32 needs a clean 3.3V supply which IC3 supplies and secondly, as you pointed out, it makes measuring voltages easier. MMBasic will not be worried if their is no USB signal on D+ and D-. As twofingers said, a USB power pack intended for charging a mobile phone is the simplest and cheapest battery pack for the job. Geoff Geoff Graham - http://geoffg.net |
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| BrianP Senior Member  Joined: 30/03/2017 Location: AustraliaPosts: 292 |
Why not just feed 7v - 12v in the external power jack? Not quite as efficient I know but you then would not have to bother with any form of regulated power. I'm thinking maybe a 7AH gel battery?  |
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Chopperp Guru Joined: 03/01/2018 Location: AustraliaPosts: 1097 |
@ BrianP The regulators will get too hot feeding in 12V from a Gel Battery From another Brian P ChopperP |
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| BrianP Senior Member Joined: 30/03/2017 Location: AustraliaPosts: 292 |
No different from using a 12v plugpack! On mine I have a simple flag heatsink on the 5v reg (it's the only one involved) - been running this way for several years with no drama. I did say it was less efficient tho... |
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TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 6283 |
I ran mine of a 7 or 9 V switch-mode rather than straight from nominal 12V sources which end up at 14V when charging batteries. The cheap alternative was a 5W resistor in the 12V supply line to drop it to 9V If a gel battery is not too big, I would replace the 5V regulator with a 5V switch-mode fro a neater solution. Not that I am known for being neat. Jim VK7JH MMedit |
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| Chopperp Guru Joined: 03/01/2018 Location: AustraliaPosts: 1097 |
Fair enough. I do have a heatsink on mine & it's running cool, but I'm only putting in 9V. I should have said that the regulator would get hot without a heatsink. ChopperP |
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| Poppy Guru Joined: 25/07/2019 Location: GermanyPosts: 486 |
Thanks for all your input, just keep on as I am getting good new ideas! So far I think there are two ways I could go, for example running a fishfeeder. At least the CMM should manage a 12VDC gear motor doing the feeding process and parallelly one or more DS18B20 for monitoring air and water temperature and processing all data with an output on a disengageable 7 inch/12VDC monitor. For keeping only the PIC running a 5V powerpack seems to be best but for backing up the complete machine I consider a 12V battery. In that case I assume an external regulation bypassing the 7805 (with a heatsink reaching about 50°C at 12V, showing general energy loss) for using the USB socket. There are several chinese buck/boost/automatic modules I got to try out comparing the energy consumption but if not satisfying what specific regulator would you recommend (12/14 V to 5V) staying cool at about 1A-1.5A max. with minimal loss? Another question: As the TC-IC is so important for the accuracy of the measurement what is the difference to a MicroMite having none? Andre ... such a GURU? | ||||
| Chopperp Guru Joined: 03/01/2018 Location: AustraliaPosts: 1097 |
On one of my uMite projects where I drive a 40 x 4 alpha numeric back light LCD (which is not a straight forward task in itself), I use an oldish automotive type 12-24V to 5V USB adapter I had on hand. This is connected to an old Laptop battery via a BMS & a 14V plug pack charger. The 9V supply for my CMM actually runs off a small 240V - 240V UPS I picked up cheaply. Probably not the most energy or cost efficient way of of doing it thinking about it. ChopperP |
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| Volhout Guru Joined: 05/03/2018 Location: NetherlandsPosts: 5089 |
In stead of modifying the CMM, use one of those cheap chineese buck convertors to drop the 12/14V to 9V and feed it in the standard way. Typically these convertors are not the finest with respect to switching noise. The 7805 in the CMM will do a good job filtering out the switch noise. Success Volhout PicomiteVGA PETSCII ROBOTS |
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| Poppy Guru Joined: 25/07/2019 Location: GermanyPosts: 486 |
Thanks! I am considering for the whole device a general 12VDC supply adapted from 230VAC mains and inline a 12VDC backup battery. Now your idea of feeding the CMM power jack with 9V by cascading regulators is great. I will test it for the energy consumption and heating! Andre ... such a GURU? | ||||
| WhiteWizzard Guru Joined: 05/04/2013 Location: United KingdomPosts: 2944 |
@Poppy, Just out of curiosity, why are you wanting to run the CMM on batteries? The CMM is generally used with a VGA monitor which typically itself will need a mains supply. That said, you can use a cheap TFT setup with a VGA input and run everything on a battery. Then the question becomes why not just use a Micromite IF you are using the Maximite in an embedded scenario? Less power than a Maximite so hence battery would last a lot longer. No doubt you have very specific reasons that lead to your original question - I am simply provoking thoughts that maybe you have not considered? All said and done, I have often run a CMM from a battery, but in my case it was a simple lack of a spare mains socket! I tend to use the readily available battery-packs that are designed to re-charge mobile phones. Using a decent one allows you to feed in a charging supply (to the battery pack) whenever you’re near a mains socket, and when ‘in the field’ it will deliver 5v into the CMM (on the USB input). No need to use delicate (and potentially dangerous) separate lithium batteries and charger modules. The Duinomite did an ok job at implementing a recharging circuit but by using the above method, there really is no need to go to the length of designing a battery circuit for the CMM (or micromite). Please do share the technique that you decide to proceed with as it’s always useful to learn potentially new and successful ideas that people come out with. WW |
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| WhiteWizzard Guru Joined: 05/04/2013 Location: United KingdomPosts: 2944 |
@Poppy, Just out of curiosity, why are you wanting to run the CMM on batteries? The CMM is generally used with a VGA monitor which typically itself will need a mains supply. That said, you can use a cheap TFT setup with a VGA input and run everything on a battery. Then the question becomes why not just use a Micromite IF you are using the Maximite in an embedded scenario? Less power than a Maximite so hence battery would last a lot longer. No doubt you have very specific reasons that lead to your original question - I am simply provoking thoughts that maybe you have not considered? All said and done, I have often run a CMM from a battery, but in my case it was a simple lack of a spare mains socket! I tend to use the readily available battery-packs that are designed to re-charge mobile phones. Using a decent one allows you to feed in a charging supply (to the battery pack) whenever you’re near a mains socket, and when ‘in the field’ it will deliver 5v into the CMM (on the USB input). No need to use delicate (and potentially dangerous) separate lithium batteries and charger modules. The Duinomite did an ok job at implementing a recharging circuit but by using the above method, there really is no need to go to the length of designing a battery circuit for the CMM (or micromite). Please do share the technique that you decide to proceed with as it’s always useful to learn potentially new and successful ideas that people come out with. WW |
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| WhiteWizzard Guru Joined: 05/04/2013 Location: United KingdomPosts: 2944 |
@Admin (Glenn) Can’t get out of this loop we’re it resubmits the post!  |
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| Poppy Guru Joined: 25/07/2019 Location: GermanyPosts: 486 |
Thanks for sharing your Thoughts WhiteWizzard I already had those myself and of course the Micromite generally is the adequate device for embedded jobs. Also I am not a friend of lithium batteries, but for running my planned set I do not need mains, just 12VDC and therefore a lead acid battery would be best, so that even the TFT is supplied whenever I want to switch it on in between, just for short monitoring. I just want to check out some practical frontiers for getting some new ideas and experiences, I don´t think that the CMM is an ideal solution for such simple jobs, but if I go further then it could run a complete aquarium system, probably as the central unit enslaving some uMites or Duinomites, of course then mains will be the solution for general power supply. How long did which capacity of your 5V battery-packs roughly but practically last? Sure, but it could take some time! Andre ... such a GURU? | ||||
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