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Forum Index : Microcontroller and PC projects : power?
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elchucko Regular Member  Joined: 09/11/2011 Location: United StatesPosts: 86 |
New to this forum & Maximite. What is the power source of this computer? |
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sparkey Senior Member  Joined: 15/06/2011 Location: AustraliaPosts: 819 |
if you have an altroincs original its around 9 to 12 volts dc if you have a maxi by another manafactyrer then it will be arond the same as they run general;ly off 3.3 volts chip voltage a small plug pack at 500 ma will be fine... technicians do it with least resistance |
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BobDevries Senior Member Joined: 08/06/2011 Location: AustraliaPosts: 266 |
My (Altronics) Maximite runs quite happily from the USB power. Regards, Bob Devries Dalby, QLD, Australia |
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Keith @ Senior Member Joined: 19/06/2011 Location: AustraliaPosts: 167 |
Elchucko Depends on which implementation ... Original Maximite 7-15 volt DC plug pack as it has both a 3.3v & a 5v regulator on board The miniMaximite 3.3v DC but it doesn't have a regulator on board Then there are a number of other implementations which you will need to check their individual requirements but I would say if it runs USB then it will need 5v & 3.3v and if no USB then it will only need 3.3v but also check if they have regulators and if they do then a slightly higher voltage (+2.0v). Check the specifications on each product to be sure. And the higher the voltage over the +2.0v then the need for a heatsink on the regulator. Keith The more we know, the more we know we don't know ! |
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| elchucko Regular Member Joined: 09/11/2011 Location: United StatesPosts: 86 |
The Maximite-SM1sold through Dontronics is the computer PCB I am questioning. A photo of the unit shows a light green connector strip for a gnd/gnd/5v input. A schematic shows an external power source (?) jack that is connected to a power switch and a VR before connecting to the green power strip on the PCB. I don't see the "con 1 external power jack" on the computer or a power switch which begs the question where are the components that connect to the green power terminal? You say the computer can be powered via the USB port so therefor I do not need any other power source? Sorry if these questions may be confusing. My plan is to primarily use the Maximite as a Basic computer learning tool with the capability of being connected to a PC via the USB port on the unit. I also need the capability to use the unit "standalone" with a flat screen and a keyboard. Thank you |
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| sparkey Senior Member Joined: 15/06/2011 Location: AustraliaPosts: 819 |
ok the sm1 board you see the green three way term block ..it has two negative terminals and a positive terminal....you dont need to apply power here if you use the usb lead ...the power switching is done through diodes and there for when plugged into a PC iot will get 5 volts from the usb supply via the connecting cable also if using the front power term`s just get a 6 volt dc plug pack or a small power supply the board draws around 150 ma .. u can run it of a 6v sla battery if you want to .. the second ground on the terminal block is a spare gnd...also "R8 "is the resistor to jumper accross if you want higher sound gain...sparkey technicians do it with least resistance |
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| sparkey Senior Member Joined: 15/06/2011 Location: AustraliaPosts: 819 |
also i would sugest you go to geoffs web site and goto the maximite computer page down the bottom you will find the nesscary files for u to download technicians do it with least resistance |
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| elchucko Regular Member Joined: 09/11/2011 Location: United StatesPosts: 86 |
Suggestion where to get the "6 volt dc plug pack or a small powder supply"? This is so I can use the Maximite with a VGA and IBM keyboard. Thank you |
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| elchucko Regular Member Joined: 09/11/2011 Location: United StatesPosts: 86 |
OK I found a source for the parts. It looks like I'll need to mount a female power connector to the PCB then wire it to the green terminal. Then use a standard 6v dc power pack as external power source. Sorry I'm new at this. Thank you |
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| sparkey Senior Member Joined: 15/06/2011 Location: AustraliaPosts: 819 |
well if you have a multimeter you can either pin out the plug pack and yes also the female socket making shure you have the polearity correct like usually the centre is positive or you can cut the connector off the plug pack check the polearity again and hard wire it to the maxi ...leave some lenth of wire on the cut off plug you may re use it if you have to.... technicians do it with least resistance |
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donmck Guru  Joined: 09/06/2011 Location: AustraliaPosts: 1313 |
Have a look at this thread, and the use and acquisition of cheap AC to USB power supplies: http://www.thebackshed.com/forum/forum_posts.asp?TID=3683&PN =11 You may have several laying around the house now. But it appears the best and safest type is: http://www.ebay.com.au/itm/USB-Home-Wall-AC-Charger-Apple-iP od-iPhone-DB3-/220748143328?pt=AU_MobilePhoneAccessories&has h=item33659d5ae0 Like about a buck each including postage. (I still believe the Chinese Govt subsidizes all postage from China.) Cheers Don... https://www.dontronics.com |
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| elchucko Regular Member Joined: 09/11/2011 Location: United StatesPosts: 86 |
Thanks for the feedback! I'll check these chargers out. I have one for my Android phone but I'll get another. I'm going to see if I can find a clear plastic enclosure for the Maximite I will purchase. I would have gone with the "original" Maximite kit but they are sold out! Thank you |
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| donmck Guru Joined: 09/06/2011 Location: AustraliaPosts: 1313 |
Sold out again, good heavens. Would be nice to know how many kits they have sold. Cheers Don... https://www.dontronics.com |
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VK6MRG Guru Joined: 08/06/2011 Location: AustraliaPosts: 347 |
How many do you think would be in a production run? 100...250....500 units? Its easier to ask forgiveness than to seek permission! ............VK6MRG.............VK3MGR............ |
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pcaffalldavis Senior Member Joined: 17/10/2011 Location: United StatesPosts: 187 |
I run all my SM1s on a 9 volt bench supply. I did my first testing on a 9 volt battery. I was curious how long an alkaline could run it as a temperature sensor program was looping. I forget how long now, but it was only a few scant hours. Would it be better if I used 6 volts Don? We're all here 'cause we're not all there. |
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| sparkey Senior Member Joined: 15/06/2011 Location: AustraliaPosts: 819 |
think from mem last run was 250 approx...and pcaff try using a 6 volt sla battery u can get them in different sizes/capacity//maximite draws 140 ma approx it does stae its consumption in the manual.... technicians do it with least resistance |
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| donmck Guru Joined: 09/06/2011 Location: AustraliaPosts: 1313 |
Real problem is the MaxiMite, and DuinoMite for that matter, aren't designed to be used as a battery operated device using standard MM-Basic. The PIC32 is capable of running in low power, or sleep mode. If I recall, Geoff G. said it can be done, but you need an input interrupt pin to instruct the PIC32 to come out of sleep power mode, once you have entered it. Cheers Don... https://www.dontronics.com |
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| Olimex Senior Member Joined: 02/10/2011 Location: BulgariaPosts: 226 |
Duinomite have low frequency crystal which could be programmed to wake up the processor at certain time intervals and ability to sleep the hardware to less 30 uA, the current firmware though do not use these features |
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| sparkey Senior Member Joined: 15/06/2011 Location: AustraliaPosts: 819 |
does duinomite have a diffrent multiplyer ...low frequency xtal???? confused technicians do it with least resistance |
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| Olimex Senior Member Joined: 02/10/2011 Location: BulgariaPosts: 226 |
Duinomite have two crystals one 8Mhz and one 32Khz, so can work in low power modes with only 32Khz oscillator running which consumes very low current compared with the 8Mhz oscillator |
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