My beast of a development board is nearly ready for printing :), heres a peak. - Page 1
Forum section: electronics / projects

author: rickey1990
author_rank: Regular Contributor
timestamp: January 10, 2016, 09:40:08 pm
content: Still some modifications to do, So i wanted to make a platform for the younger generation, i wanted something that teachs the basic prinicples of electronics, Soldering, some basic electrical enginnering priniciples, power regulation, resistor colour codes, communication methods, transmitting,recieving and cross talking with other devices. Something that will work with most of the DIP package microcontrollers out there. One board that can teach someone how to not only make arduino like boards but real world projects. The circuits used are what they are - simple!

author: CM800
author_rank: Frequent Contributor
timestamp: January 10, 2016, 10:06:32 pm
content: Very nice! I would personally suggest a USB connection with an RS232 output too, saves a £15 adapter on the side.

author: penfold
author_rank: Frequent Contributor
timestamp: January 10, 2016, 10:34:59 pm
content: Looks good, except, the capacitor placement looks a little messed up, they all seem to be quite a long way from where they are actually connected. The concept is great though.

author: rickey1990
author_rank: Regular Contributor
timestamp: January 10, 2016, 11:11:47 pm
content: Thankyou, iv designed afew boards in the past but this is one id like to hopefully make a small success from, the board was going to be for older microcontrollers for building simple retro pcs, but i had afew other ideas, tryed putting them all on aboard, gets very big, so its going to be my version 1, and hopefully with time il come out with different variations. most of my time was spent working out where to put what, the board can fit wide dips and standard dip packages. the reason the bottom is left under populated is so the arm on a zif socket is easy to get to. also it will fit the arduino nano and other break out boards up to 68pins. iv also left room at the top for a isp header or jtag up to 24 pins, which can also be used to fit components and a 24 pin dip in. the rs232's are set in a way where you can use them with most pics and atmega's. the breakout pins are placed the same distance apart as the edges of a standard prototyping board.The boards and components are cheap enouth, around £1.40 per board (pcbway), bringing it up to £2, with the basic components,Max232, headers,voltage regulator ect.

author: rickey1990
author_rank: Regular Contributor
timestamp: January 10, 2016, 11:48:39 pm
content: it also just hit me i designed this for ease of use, me being left handed, iv left the left side blank :/. hopefully righties wont have any issues!

author: nctnico
author_rank: Super Contributor
timestamp: January 10, 2016, 11:56:14 pm
content: I'd put the + signs of the capacitors in the same direction. I've made a habit out of putting all the electrolytics and diodes in the same direction because it is easier to prevent and see mistakes that way. I try to do the same with chips but that is not always possible.Still I wonder: if it is for a younger generation then why not surface mounted? 1206 and SOIC (1.27mm) components are much easier to solder than through hole. It's mostly the old farts that seem to keep people away from SMT by (wrongly) thinking hand soldering surface mounted components is hard or requires special tools.

author: rickey1990
author_rank: Regular Contributor
timestamp: January 11, 2016, 12:40:16 am
content: True, Only 25, well i recon its just what your use to, was lucky enouth to go to a school which specialised in electronics, so did it every year, then did electronics and robotics at college, evan then Smd components were barely used, it was mostly all through hole.So its just what your use to, also i think it looks alot less daunting soldering something bigger in, with more room, than something smaller. nice big gap between pads, Younger i ment around 9 or 10.

author: v8dave
author_rank: Regular Contributor
timestamp: January 11, 2016, 01:05:00 am
content: C5 is the decoupling for the MAX232 and as such is WAY too far away. The design specs call for this to be as close as possible to the device. You also show this as a polarised cap on the PCB but the schematic shows this as non. I'd use ceramic X7R type for this.I have to agree with one other post and that is that I am also not sure that the other caps on the charge pump will work well that far away from the device. They should really be as close as possible to the device as you can make them. I've never seen a MAX232 used where the charge pump caps are anything but close to the device.

author: JoeO
author_rank: Frequent Contributor
timestamp: January 11, 2016, 01:27:07 am
content: You should add at least 4 screw holes near the corners. Someone may want to build a project and then mount it in a box.Looks nice. How much do you think they will cost?

author: Ian.M
author_rank: Super Contributor
timestamp: January 11, 2016, 01:37:36 am
content: It doesn't look like it would be any good for DIP package MCUs. I'm assuming the MCU is meant to go in the middle. You've got skinny tracks breaking out the four central rows of 34 pads to two 68 pin header footprints with absolutely no provision for decoupling, or for low impedance power and ground traces, or for connecting crystals + their associated caps to oscillator pins. You'd do better to have a breadboard style layout for that area, but with 6 pads per strip so 0.6" wide DIPs still have enough pads available either side, with full width traces, ground pads bottom side down the middle so Vss pins can be directly tied to ground and Vdd pins decoupled with SMD caps, a power trace down the middle topside so Vdd pins can be tied in the same way + three uncommitted rails either side of the breadboard area.Leave off the second serial port - its fairly useless without level shifting. Instead fit a USB Micro-AB socket and a micro-SD card socket.Its also missing mounting holes or anywhere sensible to put stick-on feet.