DRV 8255 vs A4988

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While I went on to explore the most suitable module to control my stepper motor. Preferably for a CNC machine, and many promising contestants showed up. Contestants include l293d, TB560, DRV8255, A4988, Rees52 This blog decides the winner.
IMG_20170504_143045

The good looking(DRV-8255) on the left is surely attractive and there doesn’t stand much difference when it comes performance with the A4988. The screw type adjustment to control the current limit is the same both the modules and might look different than yours as there are multiple chinese manufactures. Where aren’t they? Really? Handle the trim pot gently or else you might end up ruining the module

Heating was very common on both the IC’s which can be pulled down to an extent with additional usage of sink and fan cooling options. The A4988 seemed to cool off much faster when motor is not in operation. The polou IC is technically more reliable on paper. A4988 IC is tiny and might come off under intense heat and rugged usage.

On the programming front, The libraries were available combined for both of them and looked equally comfortable.

Mixing of both A4988 and DRV8255 worked fine on the CNC module. The availability of both in market is not the same, as drv8255 were found almost everywhere. And my observations below.

 

A4988 DRV8825
Availability very widely available widely available
Approx. price 225RS 185Rs
Max. theoretical current 2A 2.5A
Max. microsteps 16 32
PCB color Green / Red Purple
Stepper current adjust. trimpot Yes, near Dir pin Yes, near En pin
Typical Rs value 0.05 Ohm or
0.1 Ohm or
0.2 Ohm
0.1 Ohm
Vref formula (*) I_TripMax= Vref/(8*Rs) I_TripMax= Vref/(5*Rs)
Thermal Overload Protection (**) Yes Yes
PCB layers 2 4
Small heatsink included (***) Almost always Sometimes not
Active cooling required? Recommended Recommended
IC packaging 5x5mm 28-lead QFN 9.7×6.4mm 28HTSSOP

The judgement? Well . . .

A4988 wins. But, not by a fair margin.

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RFID BASED SMART TOLL

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Suggested prototype for Indian based toll system

This project hosts a microcontroller with a limited database consisting RFID key tags. It also maintains an amount(balance) and deducts costs based on the service utilized by the travelers. The deducted amount and existing balance is notified via sms and reflected across centralized database accessible by all the toll plazas. The same can be recharged at multiple points or via online.

 

The main advantage is however the entire system promotes the idea of going CASHLESS economy and hassle caused in waiting while paying for toll. With this RFID tag attached to the CAR, It allows the passenger to not avail but the reading and deducting process being done on the way. The toll plaza consists a segment of road with inbuilt RFID readers to enable ON THE GO deduction and access of toll system.

 

The idea can further be powered by IoT allowing users to access their toll more conveniently and government or other central agencies to collect or analyze big data on patterns of vehicle movement within the country.

 

You can find the code below.

https://drive.google.com/file/d/0B6gqs56sTt5gWEl3WGEwdXIzeEE/view?usp=sharing

 

WhatsApp Image 2017-05-10 at 10.42.10 PM